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Objective: To report the perinatal outcome of monochorionic diamniotic (MCDA) twin pregnancies complicated by twin anemia-polycythemia sequence (TAPS), according to the type of TAPS (spontaneous or postlaser) and the management option adopted., Methods: MEDLINE, EMBASE and The Cochrane Library databases were searched for studies reporting on the outcome of twin pregnancies complicated by TAPS. Inclusion criteria were non-anomalous MCDA twin pregnancies with a diagnosis of TAPS. The primary outcome was perinatal mortality; secondary outcomes were neonatal morbidity and preterm birth (PTB). The outcomes were stratified according to the type of TAPS (spontaneous or following laser treatment for twin-twin transfusion syndrome) and the management option adopted (expectant, laser surgery, intrauterine transfusion (IUT) or selective reduction (SR)). Random-effects meta-analysis of proportions was used to analyze the data., Results: Perinatal outcome was assessed according to whether TAPS occurred spontaneously or after laser treatment in 506 pregnancies (38 studies). Intrauterine death (IUD) occurred in 5.2% (95% CI, 3.6-7.1%) of twins with spontaneous TAPS and in 10.2% (95% CI, 7.4-13.3%) of those with postlaser TAPS, while the corresponding rates of neonatal death were 4.0% (95% CI, 2.6-5.7%) and 9.2% (95% CI, 6.6-12.3%), respectively. Severe neonatal morbidity occurred in 29.3% (95% CI, 25.6-33.1%) of twins after spontaneous TAPS and in 33.3% (95% CI, 17.4-51.8%) after postlaser TAPS, while the corresponding rates of severe neurological morbidity were 4.0% (95% CI, 3.5-5.7%) and 11.1% (95% CI, 6.2-17.2%), respectively. PTB complicated 86.3% (95% CI, 77.2-93.3%) of pregnancies with spontaneous TAPS and all cases with postlaser TAPS (100% (95% CI, 84.3-100%)). Iatrogenic PTB was more frequent than spontaneous PTB in both groups. Perinatal outcome was assessed according to the management option adopted in 417 pregnancies (21 studies). IUD occurred in 9.8% (95% CI, 4.3-17.1%) of twins managed expectantly and in 13.1% (95% CI, 9.2-17.6%), 12.1% (95% CI, 7.7-17.3%) and 7.6% (95% CI, 1.3-18.5%) of those treated with laser surgery, IUT and SR, respectively. Severe neonatal morbidity affected 27.3% (95% CI, 13.6-43.6%) of twins in the expectant-management group, 28.7% (95% CI, 22.7-35.1%) of those in the laser-surgery group, 38.2% (95% CI, 18.3-60.5%) of those in the IUT group and 23.3% (95% CI, 10.5-39.2%) of those in the SR group. PTB complicated 80.4% (95% CI, 59.8-94.8%), 73.4% (95% CI, 48.1-92.3%), 100% (95% CI, 76.5-100%) and 100% (95% CI, 39.8-100%) of pregnancies after expectant management, laser surgery, IUT and SR, respectively., Conclusions: The present meta-analysis provides pooled estimates of the risks of perinatal mortality, neonatal morbidity and PTB in twin pregnancies complicated by TAPS, stratified by the type of TAPS and the management option adopted. Although a direct comparison could not be performed, the results from this systematic review suggest that spontaneous TAPS may have a better prognosis than postlaser TAPS. No differences in terms of mortality and morbidity were observed when comparing different management options for TAPS, although these findings should be interpreted with caution in view of the limitations of the included studies. Individualized prenatal management, taking into account the severity of TAPS and gestational age, is currently the recommended strategy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology., (© 2021 International Society of Ultrasound in Obstetrics and Gynecology.)

Objective: Selective fetal growth restriction (sFGR) complicating twin-twin transfusion syndrome (TTTS) is associated with a 3-6-fold increased risk of fetal demise after fetoscopic laser surgery (FLS). Identifying these patients is challenging due to varying definitions of sFGR used in the literature. The objective of this study was to determine the association of three currently used definitions for sFGR with demise of the smaller twin, typically the donor, following FLS for TTTS., Methods: This was a retrospective cohort study of monochorionic diamniotic twin pregnancies undergoing FLS for TTTS between January 2015 and December 2018. Classification of the cohort as sFGR or non-sFGR was performed using three different definitions: (1) estimated fetal weight (EFW) of one twin < 10 th centile and intertwin EFW discordance > 25%, according to the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) (Definition A); (2) EFW of one twin < 3 rd centile, according to the solitary criterion for sFGR reported in a Delphi consensus (Definition B); and (3) presence of at least two of four of the following criteria: EFW of one twin < 10 th centile, abdominal circumference of one twin < 10 th centile, intertwin EFW discordance of ≥ 25% and umbilical artery pulsatility index of the smaller twin > 95 th centile, according to the contributory criteria for sFGR in monochorionic diamniotic twin pregnancies reported in the Delphi consensus (Definition C). Pearson's χ 2 and univariate and multivariate logistic regression analyses were performed to assess the association of classification as sFGR according to the different definitions with fetal demise within 48 h after FLS., Results: A total of 124 pregnancies underwent FLS for TTTS during the study period. Of these, 46/124 (37.1%) were identified as having sFGR according to the ISUOG criteria (Definition A), 57/124 (46.0%) based on EFW < 3 rd centile (Definition B) and 70/124 (56.5%) according to the Delphi contributory criteria (Definition C). There were no differences in maternal body mass index, recipient twin amniotic fluid volume, gestational age (GA) at intervention or GA at delivery between sFGR and non-sFGR cases for any of the three definitions. There were also no differences in the rates of postprocedure recipient demise or Doppler abnormalities in the recipient. Regardless of the definition used, sFGR cases showed a significantly higher rate of postprocedure donor twin demise compared with that in non-sFGR cases (Definition A: 28.3% vs 3.8%, P < 0.01; Definition B: 22.8% vs 4.5%, P = 0.02; Definition C: 22.9% vs 0%, P < 0.01). For all of the sFGR definitions, the rate of Stage-III TTTS was increased in sFGR compared to non-sFGR cases (Definition A: 65.2% vs 35.9%, P ≤ 0.01; Definition B: 59.6% vs 35.8%, P = 0.04; Definition C: 62.9% vs 25.9%, P < 0.01). All cases of donor demise met the criteria for sFGR according to Definition C. Classification as sFGR according to Definition C was associated with a significantly higher rate of post-FLS donor demise compared to Definitions A and B (χ 2 , 15.32; P < 0.01). Logistic regression analysis demonstrated that sFGR cases had an increased risk of donor demise (Definition A: odds ratio (OR), 4.97 (95% CI, 1.77-13.94), P < 0.01; Definition B: OR, 4.39 (95% CI, 1.36-14.15), P = 0.01) and that staging of TTTS was also predictive of demise (OR, 2.26 (95% CI, 1.14-4.47), P = 0.02). After adjusting for GA at intervention and stage of TTTS, the results were similar (Definition A: OR, 6.48 (95% CI, 2.11-24.56), P = 0.002; Definition B: OR, 4.16 (95% CI, 1.35-15.74), P = 0.02)., Conclusions: The rate of fetal demise following FLS for TTTS is increased in the presence of sFGR. Improving diagnosis of sFGR should improve counseling and may affect management. The Delphi method of defining sFGR based on the presence of at least two of four contributory criteria had the highest predictive value for donor demise following FLS for TTTS. © 2020 International Society of Ultrasound in Obstetrics and Gynecology., (© 2020 International Society of Ultrasound in Obstetrics and Gynecology.)

Monochorionic (MC) pregnancy is a high risk pregnancy with well-defined specific complications, such as twin-to-twin transfusion syndrome (TTTS) and twin anaemia-polycythaemia sequence (TAPS). Laser photocoagulation (LPC) is an effective treatment for both complications. In the current retrospective study, we determined the incidence of MC pregnancy complications in a tertiary care centre during a 10-year period. Single foetal death (FD) beyond 14 weeks' gestation was significantly higher when complicated by either TTTS, TAPS or selective foetal growth restriction (21.4%, 16.7% and 9.1% versus 1.6%, p <.001, p =.02 and p =.04, respectively). We also demonstrated that twins' weight discordance >20% is an independent risk factor for single or double FD after LPC. Consequently, prior to LPC, patients should be counselled that early diagnosis of TTTS, advanced Quintero stages and weight discordances >20% are potential risk factors for FD. Further studies are needed to identify additional risk factors for TTTS and TAPS outcome after LPC.Impact Statement What is already known on this subject? Monochorionic (MC) pregnancy is a high risk pregnancy with well-defined specific complications, such as twin-twin transfusion syndrome (TTTS) and twin anaemia-polycythaemia sequence (TAPS). Laser photocoagulation (LPC) is an effective treatment for both complications. What the results of this study add? The results of the current study determined the incidence of MC pregnancy complications in a tertiary care centre in Brussels, and identified that twins' weight discordance >20% is an independent risk factor for single or double foetal death after LPC. What the implications are of these findings for clinical practice and/or further research? Prior to laser coagulation, patients should be counselled that early diagnosis of TTTS, Quintero stages 3 or 4 and weight discordances >20% are potential risk factors for foetal demise. Further studies are needed to identify additional risk factors for TTTS and TAPS outcome after LPC.

Objective: Monochorionic, diamniotic (MCDA) twin pairs are predisposed to various pregnancy complications due to the unique placental angioarchitecture of monochorionicity. Few studies have evaluated the outcomes of weight-discordant MCDA pairs without selective fetal growth restriction (SFGR) or the risk factors for development of SFGR. This study aims to describe the natural history of expectant, noninvasive management of weight-discordant MCDA twins and to evaluate risk factors associated with progression to SFGR., Study Design: This was a retrospective cohort study at a single, tertiary care center in the United States. All MCDA twins with isolated intertwin weight discordance (ITWD) ≥ 20% diagnosed before 26 weeks' gestational age (GA) were included. The primary outcome of descriptive analyses was overall pregnancy outcome, incorporating both survival to delivery and GA at delivery, as defined by the North American Fetal Therapy Network. The secondary outcome was SFGR in one twin (defined as estimated fetal weight < 10% for GA) and factors associated with this progression. Only those with fetal ultrasound (US) within 4 weeks of delivery were included in this secondary analysis., Results: Among 73 MCDA pairs with ITWD, 73% had a good pregnancy outcome, with dual live delivery at a median GA of 33 weeks. Among the 34 pairs with adequate US follow-up, 56% developed SFGR. There were no differences in GA at delivery or discordance at birth between those who did and those who did not develop SFGR. There was a nonsignificant association between increasing ITWD at diagnosis and subsequent development of SFGR., Conclusion: Expectant, noninvasive management can be considered in MCDA twin pregnancies with ITWD ≥ 20% diagnosed before 26 weeks. This approach is associated with a good pregnancy outcome in the majority of cases, even after the development of SFGR in the smaller twin., Key Points: · Nearly 75% of weight-discordant mo/di twins have a good pregnancy outcome.. · Weight-discordant mo/di twins deliver at a mean gestational age of 33 weeks without invasive therapy.. · Noninvasive management should be considered for weight-discordant mo/di twins.., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: To determine the perinatal outcome of monochorionic diamniotic (MCDA) twin pregnancies complicated by selective intrauterine growth restriction (sIUGR), which were classified according to the umbilical artery (UA) Doppler flow pattern of the IUGR twin., Methods: This was a retrospective cohort study of all MCDA twin pregnancies diagnosed with sIUGR and managed at a single tertiary referral center between 2012 and 2018. Cases were classified according to the UA Doppler flow pattern of the IUGR twin as Type I (positive end-diastolic flow), Type II (persistently absent/reversed end-diastolic flow) or Type III (intermittently absent/reversed end-diastolic flow). Patients with Type-II or -III sIUGR were hospitalized at 26-28 weeks of gestation for increased fetal surveillance. Perinatal and immediate and long-term neurodevelopmental outcomes were stratified according to the UA Doppler flow pattern at the final examination. Intact survival rate was defined as the number of infants surviving without neurological impairment, divided by the total number of fetuses. Composite adverse outcome, defined as any mortality, presence of severe brain lesions on postnatal transcranial ultrasound or severe neurological morbidity, was also assessed., Results: Of 88 MCDA twin pregnancies with sIUGR included in the study, 28 underwent selective termination by cord occlusion using radiofrequency ablation, resulting in a perinatal survival rate of 89.3% and a median gestational age (GA) at delivery of 33.8 (interquartile range (IQR), 28.8-38.2) weeks for the large cotwin. Expectant management was employed in 60 cases. In 26 (43.3%) cases in the expectant-management group, the classification according to the UA Doppler flow pattern changed during gestation, resulting in 26 (43.3%) cases of Type-I, 22 (36.7%) cases of Type-II and 12 (20.0%) cases of Type-III sIUGR at the final examination. The perinatal survival rate of both twins with sIUGR Types I, II and III at the final examination was 100%, 81.8% and 75.0%, respectively (P = 0.04). Two cases of double fetal death and one case of single fetal death occurred 1-4 weeks after the Doppler pattern had changed from Type I or Type II to Type III. The median GA at delivery was 34.8 (IQR, 33.1-35.7) weeks in Type I, 30.3 (IQR, 28.6-32.1) weeks in Type II and 32.0 (IQR, 31.3-32.6) weeks in Type III (P < 0.01). The total intact survival rate was 100% for Type I, 77.3% for Type II and 75.0% for Type III (P < 0.001). Multivariate analysis demonstrated that early GA at diagnosis (odds ratio (OR), 0.83 (95% CI, 0.69-0.99); P = 0.04) and the presence of Type II or III vs Type I at the last examination (OR, 13.16 (95% CI, 1.53-113.32); P = 0.02) were associated with preterm birth < 32 weeks' gestation. Early GA at diagnosis was also associated with the composite adverse outcome (OR, 0.60 (95% CI, 0.36-0.99); P = 0.04)., Conclusions: The classification system of MCDA pregnancy complicated by sIUGR, according to the UA Doppler flow pattern of the IUGR twin at final examination, is associated with perinatal outcome. Importantly, the UA Doppler flow pattern can change during gestation, which has an impact on the risk of fetal death. Nevertheless, under strict fetal surveillance, the perinatal outcome of these pregnancies is favorable. © 2020 International Society of Ultrasound in Obstetrics and Gynecology., (© 2020 International Society of Ultrasound in Obstetrics and Gynecology.)

Objective: To analyse natural course and perinatal management in twin pregnancies discordant for digynic triploidy., Case Report: We present five cases of twins discordant for digynic triploidy. Pregnancy outcome was known for three of them. In one case, premature rupture of membranes occurred at 20 gestational weeks and both fetuses were miscarried. In two other pregnancies healthy co-twins were born at term after the triploid fetuses demise at 28 and 37 weeks. No maternal complications were observed., Conclusion: Twin pregnancies discordant for triploidy poses a challenge for perinatal management. Expectant management should be considered in digynic triploid cases., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2021. Published by Elsevier B.V.)

Objective: We present prenatal diagnosis and management of monozygotic (MZ) twins discordant for severe fetal abnormalities., Case Report: A 36-year-old woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age, and hydrops fetalis, a giant cystic hygroma of 5 × 3.5 cm and left hydronephrosis in a co-twin. The other co-twin was structurally normal. Amniocentesis revealed a karyotype of 46,XY in both co-twins. Simultaneous polymorphic DNA marker analysis using the DNAs extracted from maternal blood and uncultured amniocytes confirmed MZ twinning. The woman underwent a successful selective fetal reduction by radiofrequency ablation at 22 weeks of gestation. At 28 weeks of gestation, premature rupture of membranes occurred, and a 1280-g normal male baby and a 275-g dead malformed co-twin were delivered. The normal co-twin was phenotypically normal and was doing well at age seven weeks., Conclusions: Prenatal diagnosis of MZ twins discordant for structural abnormalities should include a differential diagnosis of MZ twinning, and a zygosity test is necessary under such a circumstance., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2020. Published by Elsevier B.V.)

Objectives: To evaluate the natural history and outcome of selective fetal growth restriction (sFGR) in monochorionic diamniotic (MCDA) twin pregnancy, according to gestational age at onset and various reported diagnostic criteria, and to quantify the risk of superimposed twin-to-twin transfusion syndrome (TTTS)., Methods: This was a cohort study of MCDA twin pregnancies that had their routine antenatal care from the first trimester at St George's Hospital, London, UK. Pregnancies had ultrasound examinations every 2 weeks at 16-24 weeks and then every 2-3 weeks until delivery. The diagnostic criteria for sFGR were estimated fetal weight (EFW) of one twin < 10 th centile and intertwin EFW discordance ≥ 25%. We also applied other diagnostic criteria reported in a recent Delphi consensus. Pregnancies in which the diagnosis of TTTS was made before that of sFGR were not included in the analysis. Pregnancies that underwent fetal intervention for sFGR were excluded. The incidence of sFGR was compared between the different diagnostic criteria, overall and according to gestational age at onset. In all subsequent analyses, cases of sFGR included those diagnosed according to any of the criteria. The Gratacós classification of sFGR was applied (Type I, II or III). Pregnancy outcomes included miscarriage, intrauterine death, neonatal death and admission to the neonatal unit. Comparisons between groups were carried out using the Mann-Whitney U-test for continuous variables and the chi-square or Fisher's exact test for categorical variables., Results: The analysis included 287 MCDA twin pregnancies. According to the International Society of Ultrasound in Obstetrics and Gynecology diagnostic criteria, the incidence of early (< 24 weeks) sFGR was 4.9%, while that of late sFGR was 3.8%. When applying the various diagnostic criteria, the incidence of early sFGR varied from 1.7% to 9.1% and that of late sFGR varied from 1.1% to 5.9%. In early-onset cases, the incidence of Type I sFGR was 80.8%, that of Type II was 15.4% and that of Type III was 3.8%. The corresponding figures in late-onset cases were 94.4%, 5.6% and 0%. The incidence of superimposed TTTS was 26.9% in cases affected by early-onset sFGR and 5.6% in those affected by late-onset sFGR. The incidence of perinatal death was 8.0% in early-onset sFGR and 5.6% in late-onset sFGR (P = 0.661). Admission to the neonatal unit occurred in 61.0% and 52.9% of cases, respectively (P = 0.484)., Conclusions: In MCDA twin pregnancies, early-onset sFGR is slightly more common than is late-onset sFGR, although this difference was not significant, and is associated with worse perinatal outcome. The incidence of Types II and III sFGR is higher in early-onset sFGR. The incidence also varies according to the diagnostic criteria used, which supports the use of standardized international diagnostic criteria. Superimposed TTTS is more common in early- than in late-onset sFGR. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd., (Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.)

In 1984, Hrubec and Robinette published what was arguably the first review of the role of twins in medical research. The authors acknowledged a growing distinction between two categories of twin studies: those aimed at assessing genetic contributions to disease and those aimed at assessing environmental contributions while controlling for genetic variation. They concluded with a brief section on recently founded twin registries that had begun to provide unprecedented access to twins for medical research. Here we offer an overview of the twin research that, in our estimation, best represents the field has progress since 1984. We start by summarizing what we know about twinning. We then focus on the value of twin study designs to differentiate between genetic and environmental influences on health and on emerging applications of twins in multiple areas of medical research. We finish by describing how twin registries and networks are accelerating twin research worldwide.

Intraventricular hemorrhage is bleeding into the fluid-filled areas (ventricles) inside the brain. The condition occurs most often in babies that are born premature, growth restricted and twins pregnancies. Abnormal platelets number or functions are responsible greatly for this condition. We presented here a pregnant woman had thrombasthenia at 28 weeks of gestation with ultrasound findings of intraventricular haemorrhage in her both ICSI twin's fetuses., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Background: Monochorionic twin pregnancies are high-risk, however at present, no screening test is available to predict which monochorionic twin pregnancy will develop complications., Objective: We sought to assess ability of first-trimester pregnancy-related factors (ultrasound measurements, maternal characteristics, biomarkers) to predict complications in monochorionic twin pregnancies., Data Sources: Data sources were MEDLINE, Embase, ISI Web of Science, CINAHL, the Cochrane Central Registration of Controlled Trials and Research Registers, and Google Scholar, from inception to May 12, 2017. Gray literature and bibliographies of articles were checked., Study Eligibility Criteria: Studies that reported ultrasound measurements, maternal characteristics, or potential biomarkers, measured in the first trimester in monochorionic-diamniotic twin pregnancies, where the potential prognostic ability between the variable and twin-twin transfusion syndrome, growth restriction, or intrauterine fetal death could be assessed, were included., Study Appraisal and Synthesis Methods: Quality assessment was evaluated using the Strengthening the Reporting of Observational Studies in Epidemiology checklist by 2 reviewers independently. For meta-analysis, odds ratios using a random effects model, or standardized mean difference were calculated. If a moderate association was found, the prognostic ability was evaluated by calculating the sensitivity and specificity. Risk of heterogeneity was reported as I 2 and publication bias was visually assessed by funnel plots and quantitatively by Egger test., Results: In all, 48 studies were eligible for inclusion. Twenty meta-analyses could be performed. A moderate association was demonstrated in 3 meta-analyses, between: nuchal translucency >95th centile in one/both fetuses and twin-twin transfusion syndrome (odds ratio, 2.29 [95% confidence interval, 1.05-4.96], I 2  = 6.6%, 4 studies, 615 pregnancies); crown-rump length discordance ≥10% and twin-twin transfusion syndrome (odds ratio, 2.43 [95% confidence interval, 1.13-5.21], I 2  = 14.1%, 3 studies, 708 pregnancies); and maternal ethnicity and twin-twin transfusion syndrome (odds ratio, 2.12 [95% confidence interval, 1.17-3.83], I 2  = 0.0%, 5 studies, 467 pregnancies), but none demonstrated a prognostic ability for any outcome under investigation., Conclusion: It is not currently possible to predict adverse outcomes in monochorionic twin pregnancies. We have revealed a lack of research investigating first-trimester biomarkers in monochorionic twin pregnancies. Different assessment methods and definitions of each variable and outcome were an issue and this highlights the need for a large cohort study to evaluate these factors., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The rarity and complexity of conjoined twins creates a challenge for prenatal planning, delivery resuscitation, and postnatal management. The modality of simulation offers a safe practice environment for a multidisciplinary group consisting of neonatal providers, nurses, respiratory therapists, and surgeons in which to identify and address clinical decision making, procedural, and behavioral plans related to routine and emergency care of these patients. Simulation-based clinical rehearsals (SbCR) provide a unique opportunity to prepare for rare, complex, and patient specific clinical procedures and scenarios. This primer serves as a revisable tool that promotes the development of proper timing, technique, and confidence to allow for an optimal setting for delivery of safe care to conjoined twins. We describe the development and implementation of a simulation approach to all stages of care from the antenatal life, NICU care, to preparation for postnatal separation of conjoined twins., (Copyright © 2018. Published by Elsevier Inc.)

In the decades since the introduction of ultrasound into routine obstetric practice, the advantages of ultrasound have moved beyond the simple ability to identify multiple pregnancies antenatally to the possibility of screening them for fetal anomalies, pre-eclampsia, preterm birth, and the complications specific to monochorionic pregnancies. Screening studies have often excluded twins because physiological differences impact on the validity and sensitivity of the screening tests in routine use in singletons, and therefore, the evidence of screening performance in multiple pregnancy lags behind the evidence from singleton pregnancies. In general, most pregnancy complications are more common in twin pregnancy, but screening tests are less accurate or well validated. In this review article we present the current state of the evidence and avenues for future research relating to the use of ultrasound and screening for complications in twin pregnancies, including the monochorionicity-related pathologies, such as twin-twin transfusion syndrome, selective growth restriction, twin anaemia-polycythaemia sequence and twin reversed arterial perfusion sequence., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Pentalogy of Cantrell (PC) is characterized by midline supraumbilical abdominal wall defect, lower sternum defect, anterior diaphragmatic and pericardial defect, and congenital cardiac anomalies. Several etiological influences have been postulated, however, most of the reported cases are sporadic. In addition, evidence for mechanical teratogenesis in PC is limited. Here, we describe in one dichorionic twin with complete PC, additional severe intrauterine amputations (mainly head and neck) not previously reported resultant from mechanical teratogenesis. This morphologic constellation prompts us to emphasize the consideration of this etiological influence and provides further evidence. In fact, the pattern of anomalies in the affected fetus provides new insight into the severity and presentation of PC due to mechanical teratogenesis, which is a significant etiological consideration in clinical evaluation and implies that the syndrome involves a complex defective fetal development.

Objectives: The purpose of this systematic review is to provide a comprehensive overview on the clinical course, perinatal outcome, and effectiveness of prenatal management options for pericardial teratoma., Methods: A comprehensive search including Ovid MEDLINE, Ovid EMBASE, and Scopus was conducted from inception to September 2016. All studies that reported the prenatal course of pericardial teratoma in singleton or twin gestations were considered eligible. Standardized forms were used for data abstraction by two independent reviewers., Results: Out of 217 screened abstracts, 59 studies reporting 67 fetuses with pericardial teratoma were included. Twenty-three singleton fetuses and 3 fetuses in twin gestations underwent prenatal treatment, and 20 (76.9%) of them were hydropic at the time of intervention. Of those, 15/20 (75%) had a favorable outcome. In the non-intervention group (n = 41), 26 (63.4%) developed hydrops, and out of those, 8 (30.8%) had a favorable outcome., Conclusion: Prenatal fluid drainage and other prenatal techniques have been utilized in the treatment of intrapericardial teratoma. While most fetuses tolerated pericardiocentesis, the neonatal benefit of this procedure is still uncertain, and outcomes of other interventions had variable success. Prenatal intervention for pericardial teratoma may be an option in specialized units but, given the maternal and fetal risks, needs careful consideration. © 2017 John Wiley & Sons, Ltd., (© 2017 John Wiley & Sons, Ltd.)

Objective: To study fetal aortic isthmus (AoI) shunt dynamics in monochorionic (MC) twins., Methods: Normal and complicated MC pregnancies were prospectively enrolled. The relationship of isthmus flow index (IFI) with Doppler parameters of umbilical artery (UA), descending aorta, middle cerebral artery, and ductus venosus and with left and right ventricular cardiac output and stroke volume was studied., Results: The IFI was obtained in 180 examinations from 48 pregnancies (24 twin-twin transfusion syndrome, TTTS; 4 selective intrauterine growth restriction, sIUGR; 12 TTTS + sIUGR; and 8 uncomplicated). Median gestational age was 20.9 weeks. AoI diastolic flow was reversed in three cases. UA pulsatility index (PI) and ductus venosus-PI z-scores were negatively correlated with the IFI (r s -0.40 and -0.26, respectively, p < 0.001). Regression analysis identified only UA-PI as a determinant of the IFI (p < 0.001). The IFI was significantly correlated with left ventricular cardiac output and stroke volume. It did not differ between TTTS donors and recipients. sIUGR fetuses had significantly lower IFI compared with normal-grown counterparts (p < 0.001)., Conclusion: In MC gestations, AoI shunting is predominantly determined by placental flow resistance, while cerebral impedance and volume status have no impact. In MC twins, the relationship between AoI flow and outcome deserves further study in the setting of sIUGR. © 2017 John Wiley & Sons, Ltd., (© 2017 John Wiley & Sons, Ltd.)

Introduction: Umbilical cord occlusion (UCO) utilizing laser photocoagulation is often not considered an option for selective termination after 20 weeks of gestation due to reported limitations of the procedure because of umbilical cord size. We compared outcomes after laser umbilical cord occlusion (L-UCO) before and after 20 weeks of gestation., Materials and Methods: We examined all patients with monochorionic- diamniotic twins and higher-order multiples (monoamniotic excluded) that underwent L-UCO at our facility between 2006 and 2014. Statistical analysis was performed using Fisher's exact and Kruskal-Wallis tests as appropriate., Results: Of 43 L-UCO cases, 11 cases (25.6%) had a discordant anomaly, and 32 cases (74.4%) had twin reversed arterial perfusion (TRAP) sequence. We achieved complete vascular occlusion in 100% (43/43) of cases of attempted L-UCO. There were 22 cases (51.2%) with gestational age ≤20 weeks, and 21 cases (48.8%) with gestational age >20 weeks. Perioperative patient characteristics and outcomes did not differ between the two groups. Survival rates were 90.9% (20/22) and 100% (21/21) at ≤20 weeks of gestation and >20 weeks of gestation, respectively., Discussion: The results of this study suggest that L-UCO is a reasonable surgical modality for patients prior to and beyond 20 weeks of gestation., (© 2016 S. Karger AG, Basel.)

Purpose: 1) To evaluate and classify the indications for fetal brain MRI in a tertiary referral center. 2) To assess the contribution of fetal brain MRI to fetal neurosonography., Materials and Methods: A retrospective study in a tertiary medical center during a two-year period (2011 - 2012) included pregnant women who underwent fetal brain MRI. MRI was implemented at 32 weeks of gestation unless a severe abnormality possibly requiring earlier medical intervention was suspected., Results: 633 patients were included, 40 (6.3%) underwent repeated examinations with a total of 733 fetal MRI scans. Patients were classified to three main indication cohorts: Suspected primary brain anomaly (52.9%), non-CNS disorders (32.5%) and obstetrical complications (14.6%). These cohorts were further divided into 16 separate groups with lateral ventricle abnormalities being the most common (23.7%), followed by exposure to TORCH (17.5%) and cerebral cortex abnormalities (13%). 149 (19.3%) fetal MRI scans demonstrated additional findings. Repeated examinations were commonly implemented in complicated monochorionic-biamniotic (MCBA) twin pregnancies (34.6%) and in cases of supra-tentorial cysts (19%). The average gestational age for MRI scan in the MCBA group was 26 ± 5 weeks in comparison to ≥ 31st weeks in all other groups (p < 0.001)., Conclusion: The current study describes a detailed picture of fetal brain MRI indications. Most patients were referred because of CNS anomalies. The impressive diversity of 16 separate entities emphasizes the expanding use of fetal brain MRI. Complicated MCBA pregnancies, which may have dramatic events, constitute a unique challenge due to early and repetitive MRI examinations and may serve as a role model for the contribution of fetal MRI during antenatal evaluation. The contribution of MRI to prenatal evaluation in various indications is discussed., (© Georg Thieme Verlag KG Stuttgart · New York.)

Twin anemia-polycythemia sequence (TAPS) is recognized increasingly antenatally by the demonstration of an anemic twin and a polycythemic cotwin using the middle cerebral artery peak systolic velocity (MCA-PSV). While the MCA-PSV has been shown to correlate well with anemia in singleton fetuses, the evidence to support its use to diagnose fetal polycythemia appears to be less clear-cut. We aimed to evaluate fetal, neonatal and adult literature used to support the use of MCA-PSV for the diagnosis of polycythemia. Comprehensive literature searches were performed for ultrasound evidence of polycythemia in the human fetus, neonate and adult using key search terms. Only manuscripts in the English language with an abstract were considered for the review, performed in June 2014. Fifteen manuscripts were found for the human fetus, including 38 cases of TAPS. Nine of these defined fetal polycythemia as MCA-PSV < 0.8 multiples of the median (MoM), five used < 1.0 MoM and one used 0.8-1.0 MoM. Only two studies, involving a total of 15 cases, proposed a diagnostic level, acknowledging false-positive and -negative cases, though neither reported sensitivities or specificities. Six neonatal studies (96 neonates) demonstrated evidence of decreased cerebral velocities in polycythemia and a consequent increase with hemodilution. In the adult, five studies (57 polycythemic adults) demonstrated increased flow or velocity with hemodilution. Neither neonatal nor adult studies conclusively defined levels for screening for polycythemia. Despite widespread adoption of a cut-off of < 0.8 MoM in the published literature for the polycythemic fetus in TAPS, this is based upon minimal evidence, with unknown sensitivity and specificity. We recommend caution in excluding TAPS based purely upon the absence of a reduced MCA-PSV., (Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.)

Objective: To evaluate the diagnostic accuracy of middle cerebral artery peak systolic velocity (MCA-PSV) Doppler measurements in prediction of hemoglobin levels in twin anemia-polycythemia sequence (TAPS)., Methods: This study involved a consecutive cohort comprising monochorionic twin pregnancies complicated by TAPS managed at three European fetal medicine centers between 2005 and 2013. The accuracy of MCA-PSV, measured immediately prior to fetal hemoglobin (Hb) measurement by fetal or cord blood sampling, for prediction of anemia and polycythemia was assessed using 2 × 2 tables., Results: A total of 116 measurements (74 recorded in donors and 42 in recipients) from 43 twin pregnancies complicated by TAPS were available for analysis. MCA-PSV multiples of the median (MoM) values correlated well with Hb levels (r = - 0.86; P < 0.001). The sensitivity of MCA-PSV ≥ 1.5 MoM to predict severe anemia (Hb deficit > 5 SD below the mean) in TAPS donors was 94% (95% CI, 85-98%); specificity was 74% (95% CI, 62-83%); positive and negative predictive values were 76% (95% CI, 65-85%) and 94% (95% CI, 83-98%), respectively. The sensitivity of MCA-PSV ≤ 1.0 MoM to predict polycythemia (Hb level > 5 SD above the mean) in TAPS recipients was 97% (95% CI, 87-99%); specificity was 96% (95% CI, 89-99%); positive and negative predictive values were 93% (95% CI, 81-97%) and 99% (95% CI, 93-100%), respectively., Conclusion: MCA-PSV measurement has high diagnostic accuracy for predicting abnormal Hb levels in fetuses with TAPS., (Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.)

Unlabelled: The frequency of multiple birth pregnancies, mostly twin pregnancies, was overrepresented in four different groups of young infants with fractures and bone abnormalities. This finding suggests that fetal bone loading through fetal movement is an important determinant of fetal bone formation and its resultant bone strength., Introduction: It has been suggested that intrauterine confinement related to the multiple birth pregnancy (MBP) may lead to an increased risk for fragility fractures in young infants as a result of decreased fetal bone loading., Methods: To objectively test this idea, the frequency of MBPs was evaluated in five groups of young infants with bone disorders: (1) infants exposed to prolonged in utero exposure to magnesium, (2) infants with dietary copper deficiency, (3) infants with rickets from vitamin D deficiency, (4) infants with temporary brittle bone disease, and (5) infants with multiple unexplained fractures in which child abuse was the most likely diagnosis., Results: Compared to a control group and controlled for preterm birth, there was a statistically greater frequency of MBPs in each group., Conclusions: The results of this study suggest the following: (a) The overrepresentation of MBPs (95 % twins) in these five groups indicates that fetal bone loading is a critical determinant of fetal bone strength; (b) fetal and young infant bone strength is a multifactorial characteristic; and (c) infants from MBPs are at increased risk for fragility fractures during the first 12 months of life, and thus may be mistakenly diagnosed as victims of child abuse.

To date ten sets of monozygotic twins with neuroblastoma have been reported in the literature. Twin-to-twin in utero metastasis have been proposed as the mechanism of tumor development in the second twin; based on similar pathology, presence of metastatic disease, absence of a primary tumor, and/or later presentation in the second twin. Hereditary neuroblastoma has not been described in this context. We propose that primary neuroblastoma can occur in monozygotic twins without twin-twin transmission; due to the different ages of presentation, histology, ploidy, and tumor behavior., (© 2013 Wiley Periodicals, Inc.)

We report on the pre- and postnatal cytogenetic, molecular genetic and clinical findings in monochorionic-diamniotic twins discordant for trisomy 18. Structural anomalies were identified in one of the twins on prenatal ultrasound examination at 20 weeks' gestation and sampling of amniotic fluid from both sacs was performed for karyotyping. This revealed trisomy 18 in the twin with abnormalities and a normal karyotype in the other twin. Elective Cesarean section was performed at 31 + 5 weeks and the aneuploid twin died shortly after delivery. The surviving twin showed low-grade mosaicism for trisomy 18 on postnatal analysis but has shown normal development. For prenatal diagnosis in monochorionic-diamniotic twin pregnancy the sampling of both amniotic sacs is recommended, especially if one twin has structural anomalies on ultrasound scan., (Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.)

Objective: To investigate the clinical features of the abnormal chromosome karyotypes in twin pregnancies complicated with fetal malformations., Methods: Totally 181 twin pregnancies (362 fetuses) in which one or two fetuses had abnormalities diagnosed by ultrasound were referred to the First Affiliated Hospital of Sun Yat-Sen University from January, 2000 to September, 2010. They were divided into different groups according to (1) maternal age: the cases with maternal age ≥ 35 were divided into advanced pregnancy group (105 fetuses), and those with maternal age < 35 were divided into young pregnancy group (203 fetuses); (2) conceived method: those conceived by assisted reproductive technology were divided into assisted reproductive group (81 fetuses), and the natural conception pregnancies were divided into natural conception group (227 fetuses); (3) chorionicity: the monochorionic twin (MCT) pregnancies were divided into MCT group (123 fetuses), and the dichorionic twin (DCT) pregnancies were divided into DCT group (185 fetuses); (4) structural abnormalities: 205 fetuses with structural abnormalities were divided into the abnormal fetal group, and 103 fetuses without structural abnormalities were divided into the normal fetal group. All fetuses were examined by the ultrasound and chromosomes were examined in 308 fetuses., Results: (1) The karyotype of fetuses: among 181 twin pregnancies, 23 cases had chromosomal abnormalities in 1 or 2 fetuses (12.7%, 23/181), and chromosomes were examined in both fetuses in 20 of 23 cases. Twenty-six of 308 fetuses were found with abnormal chromosomes (8.4%, 26/308), and the aneuploid was the most common type of abnormal karyotypes (53.8%, 14/26). Twenty-one of 205 fetuses with malformations were found with abnormal karyotypes (10.2%, 21/205). (2) Seven of 123 fetuses in MCT group were with abnormal karyotypes (5.7%, 7/123), and 19 of 185 fetuses in DCT group were with abnormal karyotypes (10.3%, 19/185). There was no statistical difference of abnormal chromosome incidence between the two groups. There were 14 fetuses with aneuploid in DCT group (7.6%, 14/185); but there was no fetus with aneuploid in MCT group. There was statistical difference between these two groups. In two cases of DCT group, only one fetus with malformation received chromosome examination because another fetus was dead, and the karyotypes were trisomy 21 and trisomy 18 respectively. Both fetuses of the rest 17 cases received chromosome examination, and the chromosomes of both fetuses in each pregnancy were different. Fifteen of 19 fetuses with abnormal chromosomes in DCT group were complicated with structural abnormalities, and 7 fetuses of 4 twin pregnancies in MCT group were with chromosomal abnormalities. (3) The comparison of the abnormal karyotype incidence between the advanced pregnancy group and young pregnancy group: the abnormal karyotype incidence of the advanced pregnancy group was 7.6% (8/105), and that was 8.9% (18/203) in young pregnancy group. There was no statistical difference between the two groups (P > 0.05). Six of 105 fetuses in advanced pregnancy group were aneuploids (5.7%, 6/105), and 8 of 203 fetuses in young pregnancy group were aneuploids (3.9%, 8/203). The aneuploid incidence in advanced pregnancy group was significantly higher than that in young pregnancy group (P < 0.05).(4) The comparison of the abnormal karyotype incidence between the assisted reproductive group and the natural conception group: 11 of 81 fetuses were with the abnormal karyotypes in assisted reproductive group (13.6%, 11/81), and 15 of 227 fetuses were with the abnormal karyotypes in assisted reproductive group (6.6%, 15/227). There was statistical difference between the two groups (P < 0.05). There were 7 fetuses with the aneuploid in assisted reproductive group (8.6%, 7/81) and 7 fetuses with the aneuploid in natural conception group (3.1%, 7/227), which showed no statistical difference (P > 0.05). (5) The comparison of the abnormal karyotype incidence between the abnormal fetal group and normal fetal group: 21 of 205 fetuses in abnormal fetal group were with abnormal karyotypes (10.2%, 21/205), and 5 of 103 fetuses in normal fetal group were with abnormal karyotypes (4.9%, 5/103). There was no statistical difference (P > 0.05). 13 fetuses in abnormal fetal group were with the aneuploid (6.3%, 13/205), and only one fetus in normal fetal group was aneuploid (1.0%, 1/103). There was statistical difference between the two groups (P < 0.05)., Conclusions: Aneuploid is the most common abnormal karyotype in twin pregnancy complicated with fetal abnormalities, especially trisomy 21. Aneuploid mainly occurs in only one fetus of DCT, and chromosomal discordance is usually found in DCT. While in MCT, the twin fetuses with the same abnormal karyotype may have different phenotypes. The results suggest that it is necessary to analyze both karyotypes of twins even if only one fetus is complicated with structural abnormalities.

Introduction: Conjoined twinning is an extremely rare anomaly. Very few diagrammatic descriptions are provided for the various hepatobiliary anomalies seen in these twins. We aimed to review our experience with the various subtypes of hepatobiliary anomalies and their association with the inability to separate as well as provide diagrammatic descriptions of these anomalies., Methods: We retrospectively reviewed our experiences within separating twins. We reviewed patterns of hepatobiliary anomalies and the required investigations and intraoperative workups., Results: Of the 60 cases we evaluated, 28 were successfully separated. The reasons for nonseparation were possession of: a single heart, major communicating hearts, or major chromosomal anomalies. The liver was involved in 17 cases (60.7%) in the operative group and 23 cases (71.8%) in the nonoperative group. All cases had a computed tomographic scan and ultrasound as preoperative workup. Only 2 cases required a magnetic resonance cholangiopancreatography for preoperative evaluation. Intraoperative ultrasound was not used, and only 3 cases required an intraoperative cholangiogram. Diagrammatic depictions of the various categories of anomalies are presented., Conclusion: In our experience, we did not find hepatobiliary anomalies to be the sole reason for inseparability in any of the conjoined sets. Hepatobiliary anomalies seem to be more frequent in the nonseparable group., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The articles collected together in this issue describe first-trimester screening for a variety of complications. With the advance of both technology and research, early pregnancy screening is becoming ever more sophisticated and complex. While there are clear benefits to most women receiving early reassurance that their baby is developing as expected, there is no evidence to suggest that an earlier prenatal diagnosis has less long-term emotional impact than at later gestations. The poignancy of ultrasound images for many parents means that it can be especially difficult to manage the anxiety when an ultrasound marker is highlighted as potential cause for concern. They can then face a journey of anxiety-laden uncertainty, which can extend through much of the pregnancy, and even beyond. Professionals involved in screening need to recognise and acknowledge such adverse side-effects and develop the skills necessary to help parents understand and cope with the uncertainties inherent in the process., (Copyright © 2011 John Wiley & Sons, Ltd.)

The patients were infant male twins born by cesarean delivery following a healthy pregnancy at 36 weeks' gestation to unrelated parents. At 4 months of age, twin 2 presented with hepatomegaly and a right suprarenal mass. Resection of an adrenal tumor and a liver tumor biopsy were performed. Twin 1 had no symptoms at 4 months of age. Screening by abdominal ultrasonography showed multiple masses in the liver but no adrenal mass. Metaiodobenzylguanidine scintigraphy showed positive findings in multiple liver masses. A laparoscopic biopsy for a liver tumor was performed. All primary tumor and liver tumor specimens from twin 2 and the liver tumor of twin 1 had the same histologic classification of neuroblastoma and nearly identical genetic aberrations, including a chromosome gain or loss using array-comparative genomic hybridization. From these clinical and pathologic findings and genetic analyses, we strongly demonstrate the transplacental metastatic spread from twin 2 to twin 1. In the literature, 9 pairs of concordant twin neuroblastomas, including the current twin, have been presented; and the clinical findings of 5 twin pairs may represent placental metastases from one twin with congenital neuroblastoma to the other twin. This study is the first report presenting the possibility of twin-to-twin metastasis in monozygotic twins with neuroblastoma based on an analysis of the clinical features and genetic aberrations., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Twin pregnancy is associated with a high risk of congenital malformations. This review covers the risk of such anomalies in both dizygotic and monozygotic twin pregnancies, and discusses current insights into the associations relating to zygosity, chorionicity and genetic factors. The pathological basis of specific malformations unique to the monochorionic twinning process, including conjoined twinning and twin reversed arterial perfusion (TRAP) sequence, is discussed in more detail, and factors contributing to the higher perinatal mortality rate in multiple pregnancies are addressed., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Objectives: To assess the prevalence of cord entanglement and perinatal outcome in a large series of monoamniotic twin pregnancies and to review the recent literature on similar published large series., Methods: Prospective observational study of all prenatally detected cases of monoamniotic twin pregnancies during an 8-year period in a tertiary fetal medicine unit. A Medline database review for publications since 2000 containing five or more cases of monoamniotic pregnancies that showed data on cord entanglement and perinatal outcome was also undertaken., Results: A total of 32 monoamniotic pregnancies were diagnosed during the study period, including three conjoined twins, seven pregnancies with twin reversed arterial perfusion (TRAP) syndrome, three surgical pregnancy interruptions for discordant fetal abnormality and one miscarriage before 16 weeks' gestation. The remaining 18 monoamniotic pregnancies were included in the study analysis. All monoamniotic pregnancies were complicated with antenatal cord entanglement diagnosed by B-mode and color Doppler ultrasound. There were 34 live births and a double intrauterine death diagnosed at 19 + 2 weeks' gestation. There were two late neonatal deaths, one from congenital complete heart block and the other after surgery for transposition of the great arteries. The overall perinatal loss rate was 11.1% after 16 weeks and 5.9% after 20 weeks' gestation. The cumulative rates of cord entanglement and perinatal mortality in the reviewed literature were 74% and 21%, respectively., Conclusions: Umbilical cord entanglement is present in all monoamniotic twins when it is systematically evaluated by ultrasound and color Doppler. Perinatal mortality in monoamniotic twins is mainly a consequence of conjoined twins, TRAP, discordant anomaly and spontaneous miscarriage before 20 weeks' gestation. Expectantly managed monoamniotic twins after 20 weeks have a very good prognosis despite the finding of cord entanglement. The practice of elective very preterm delivery or other interventions to prevent cord accidents in monoamniotic twins should be re-evaluated.

Short umbilical cords are associated with fetal anomalies, often including those with decreased or absent fetal movement, fetal akinesia/hypokinesia sequence, and restrictive dermopathies and aneuploidy. In normal fetuses, abnormally short umbilical cords have been associated with an increased risk of umbilical vessel hematomas, thrombosis, rupture, thrombocytopenia, cord compression, variable fetal heart rate decelerations, instrumental and operative deliveries, and fetal demise. We report a 24-year-old gravida 2, para 0 with a concordant dichorionic twin gestation, at 26 weeks' gestation, in whom sonography depicted fetuses with normal-appearing anatomy as well as short umbilical cord of the 1st twin. Increased fetal surveillance was conducted. Following delivery at 36 weeks' gestation, the presence of a short umbilical cord of the 1st twin measuring 19 cm was confirmed. Systematic review of the literature confirms that this is the first report of prenatal diagnosis of a short umbilical cord in an otherwise normal fetus., ((c) 2009 Wiley Periodicals, Inc.)

Aim: To examine the relationship between birth weight and risk of asthma in a population of twins., Methods: Birth weight of all live twins (8280 pairs) born in Denmark between 1994 and 2000 was linked to information on asthma obtained from parent-completed questionnaires at age 3-9 years. Conditional logistic regression was used to calculate the risk of asthma., Results: Subjects with a history of asthma at age 3-9 years weighed on average 122 g (95% CI 85 to 160) less at birth than subjects who had not developed asthma, p<0.001. There was a linear increase in asthma risk with decreasing birth weight, OR (per 100 g) 1.04 (95% CI 1.03 to 1.05), p<0.001. Within twin pairs, the lower birthweight twin had a significantly increased risk of asthma compared with the heavier co-twin (11.3% vs 9.9%), OR 1.30 (95% CI 1.10 to 1.54), p=0.002. The result remained significant after adjusting for sex, birth length and Apgar score, OR 1.31 (95% CI 1.03 to 1.65), p=0.027. The risk tended to be higher in monozygotic co-twins compared with dizygotic co-twins, especially for high birth weight differences., Conclusions: Low birth weight is a risk factor for asthma independently of gestational age, sex, birth length and Apgar score, but this may be due, in part, to residual non-genetic confounding factors. This finding lends support to the "fetal origins hypothesis" suggesting undisclosed prenatal determinants for the risk of asthma.

Objective: To evaluate the prevalence of and perinatal outcome associated with increased nuchal translucency thickness (NT) > 99(th) percentile in dichorionic and monochorionic twins with normal karyotype., Methods: Two hundred and six consecutive twin pregnancies (166 dichorionic and 40 monochorionic) underwent an NT scan during a 4-year period. In those with NT > 99(th) percentile and normal karyotype, we performed first- and second-trimester anomaly scans, fetal echocardiography at 14-16 and 20-22 weeks, maternal serology and, in monochorionic pregnancies, serial ultrasound examinations every other week. Perinatal outcome was recorded., Results: There were 10 (4.95%) pregnancies in which one of the fetuses had NT > 99(th) percentile and normal karyotype, including five fetuses (1.5%) in dichorionic and five (6.25%) in monochorionic pregnancies. During the same period the prevalence of NT > 99(th) percentile and normal karyotype in singleton pregnancies studied in our center was 2.6%. Among the 10 twins affected, six (60%) were diagnosed with structural abnormalities (three dichorionic and three monochorionic), and two intrauterine fetal demises occurred (one dichorionic and one monochorionic). Thus, the perinatal outcome was normal in only two of the pregnancies, one dichorionic and one monochorionic., Conclusions: The prevalence of NT > 99(th) percentile in dichorionic twins with a normal karyotype is similar to that in singletons. In monochorionic twins we confirmed previous studies reporting an increased prevalence compared with singletons. NT > 99(th) percentile with a normal karyotype in twins was associated with a high rate of fetal abnormalities and/or fetal demise (overall 80%) irrespective of chorionicity.

Objective: To compare a laparoscopy-assisted fetoscopic approach with an ultrasound-directed percutaneous approach for laser photocoagulation of placental anastomoses in cases of twin-twin transfusion syndrome (TTTS) with anterior placentation., Method: We performed a retrospective review of all cases that underwent laser ablation of placental anastomoses for TTTS with an anterior placenta at Texas Children's Fetal Center from November 2006 to November 2008. The two cohorts were identified by chart review based on the type of approach: laparoscopy-assisted vs. ultrasound-guided percutaneous uterine entry for fetoscopy. Operative and outcome data were extracted and the groups were compared using statistical methods, taking P < 0.05 as statistically significant., Results: In the 100 cases of TTTS studied, 48 had an anterior placenta. Fifteen (31%) of these underwent laparoscopy-assisted fetoscopy (LAF) while a percutaneous approach was used in the remaining 33 (69%) cases. The total procedure time was longer in the LAF group than in the percutaneous group (96.1 +/- 25 vs. 67.9 +/- 28 min; P < 0.01). There was no difference in the rate of preterm premature rupture of membranes up to 2 weeks and 4 weeks after surgery (7 vs. 15% and 13 vs. 21%, for the LAF group vs. the percutaneous group, respectively; P = 0.7). The gestational ages at delivery were similar: 30.3 +/- 4.5 weeks in the LAF group and 29.2 +/- 4.6 weeks in the percutaneous group (P = 0.32). The overall survival rate at birth was tending towards better survival in the laparoscopic group than in the percutaneous group (80 vs. 61%, respectively; P = 0.06). The neonatal survival rate was better with the LAF approach than with the percutaneous approach (80 vs. 59%, respectively; P = 0.045)., Conclusion: Laparoscopy-assisted entry of the uterus is associated with improved neonatal survival for laser photocoagulation in cases of TTTS with a complete anterior placentation.

Objectives: To explore the feasibility and added value of three-dimensional (3D) inversion rendering of the developing embryonic/fetal ventricular system, and to apply this display technique to enhance the sonographic examination of holoprosencephaly., Methods: 3D volumes of the embryonic/fetal brain were acquired from four normal fetuses at 8-11 postmenstrual weeks, and four fetuses diagnosed with holoprosencephaly between 9 and 14 postmenstrual weeks. The volumes were then analyzed offline to obtain inversion rendered 3D shapes of the ventricular systems., Results: All inversion rendering displays were successful and provided the opportunity to study normal as well as pathological aspects of the early fetal brain., Conclusions: Inversion rendering of early fetal brain ventricles is feasible and should be attempted if additional information about the early normal or pathological fetal brain is needed. It may have scientific value in embryologic or genetic studies., ((c) 2008 ISUOG. Published by John Wiley & Sons, Ltd.)

Two recent reports on recurrent cases of umbilical cord stricture (UCS) have opened the debate on the possibility of a genetic basis for this anomaly, traditionally considered to be sporadic. We present a series of 130 cases of UCS located at the fetal insertion, diagnosed among 2067 fetal and infantile autopsies performed during the last 10 years. All cases were macerated stillborn fetuses, and 54.6% were < or =20 weeks of gestational age. Our study is focused on 2 recurrent episodes and 16 cases occurring in multiple pregnancies. Among twins, males were affected more than females (2.2:1), although no statistical significance was found. Associated umbilical cord anomalies were present in 8 of 16 cases, consisting of hypocoiling (3 cases), hypercoiling (2 cases), excessive length (1 case), vascular tortuosity (1 case), and single umbilical artery (1 case). The most frequent placental finding was obliterative endovasculopathy (6 cases), probably indicating a causal relationship with UCS. Zygosity was analyzed by placental histology and/or a panel of 12 microsatellite markers to classify twins as monozygotic (8 cases) or dizygotic (8 cases). Our data prove that UCS is not a genetic condition because all 8 genetically identical twins were discordant for the anomaly and 2 dizygotic twins with UCS had co-twins also affected. Genetic factors are not implicated in UCS pathophysiology, and parents with a fetal demise due to UCS should be counseled as having a low-recurrence risk for subsequent pregnancies. Because there is not a higher incidence of UCS in multiple gestations, twinning should not be considered a risk factor for UCS.

The risk for a cardiac anomaly in a twin pregnancy is increased, particularly in monochorionic twins. This is relevant in terms of fetal diagnosis as well as for the management of the pregnancy; there are also implications for the neonatal period and possibly beyond. The risk for a cardiac abnormality depends on the type of monochorionic twin as determined by the timing of embryonic division. Prenatal identification of twin type and the relative risks for a cardiac anomaly are discussed along with theories for the aetiology of the different cardiac lesions.

Objectives: Using a unique twin approach, we examined the extent to which birth weight is determined by genetic and nongenetic factors and whether associations between birth weight and measures of glucose metabolism are of genetic or nongenetic origin., Setting/subjects: An oral glucose tolerance test (OGTT) was performed in a population-based cohort of twins including 138 same-sex monozygotic (MZ) and 214 dizygotic (DZ) twin pairs aged 55-73 years whose birth weight was known. Heritability of birth weight was determined and regression analyses with intra-twin pair differences of birth weight and measures of glucose metabolism, with and without adjustment for adult obesity, were performed., Results: The heritability of birth weight was estimated to be 38%. We demonstrated significant nongenetic associations between birth weight and measures of glucose homeostasis in MZ twins, with a reduction in fasting plasma glucose, 120 min post-OGTT plasma glucose, fasting plasma insulin and HOMA-IR index of 15.7%, 25.5%, 26.4% and 37.2%, respectively, for every 1 kg increase in birth weight. The nongenetic negative associations between birth weight and measures of glucose intolerance were independent of adult obesity, whereas the nongenetic association between birth weight and insulin resistance persisted, although not as strongly, after adjusting for current body size., Conclusions: We demonstrated a genetic component to birth weight in elderly twins. When adjusting for this influence, we found a nongenetic negative association between birth weight and glucose tolerance as well as insulin resistance that was partially independent of adult obesity. This implies that the foetal environment influences glucose homeostasis in elderly twins.

In the early 1990s Nicolaides introduced screening for trisomy 21 by fetal nuchal translucency thickness measurement with ultrasound between 11-13(+6) weeks. Already in 1866 L. Down noted that common features of patients with trisomy 21 are a skin being too large for the body and a flat face with a small nose. While detection rates for trisomy 21, given an invasive testing rate of 5%, were only 30% for screening by maternal age and 65% for screening by maternal serum triple test, the detection rate for screening by nuchal translucency combined with maternal age was 75% and this could be increased to 90% in combination with maternal serum screening (serum B-human chorionic gonadotropin and pregnancy-associated plasma protein-A) at 11-13(+6) weeks. The additional soft markers in the first trimester are the fetal nasal bone, the Doppler velocity waveform in the ductus venosus and tricuspid regurgitation and these markers can be used to further increase the detection rate of trisomy 21. In addition increased nuchal translucency thickness can also identify other chromosomal defects (mainly trisomy 13 and 18 and monosomy X) and major congenital malformations (mainly cardiac defects) and genetic syndromes.

Twin-twin transfusion syndrome (TTTS) complicates approximately 15% of monochorionic, diamniotic twin pregnancies and if untreated carries a high perinatal loss rate of between 80% and 100%, depending on the stage. The underlying pathology in TTTS appears to be an imbalanced intertwin perfusion difference, secondary to functional unidirectional arteriovenous anastomoses within a monochorionic placenta. We report two cases of monochorionic twin pregnancy complicated by TTTS, in which the pregnancies were treated by serial aggressive amnioreduction. However, the recipient twin in each pregnancy developed 'ischemic damage' to a lower limb., (Copyright 2006 ISUOG. Published by John Wiley & Sons, Ltd.)

The combination of an onphalocele, an anterior thoracic wall defect and an anterior diaphragmatic defect constitutes classical Cantrell's pentalogy. We present a case of Cantrell's pentalogy diagnosed prenataly in twins with conventional and three-dimensional sonography.

Objective: To assess the feasibility of the prenatal diagnosis using fetal neurosonography of brain injuries in the surviving fetus after the demise of a monochorionic cotwin., Methods: This was a retrospective observational study in the period 1990-2004 of monochorionic twin pregnancies with a single fetal demise. A detailed sonographic evaluation of the intracranial anatomy of the surviving twin had been performed whenever possible using a multiplanar approach and from 1999, fetal magnetic resonance imaging was offered as well. Postnatal follow-up was obtained in all cases., Results: In six of nine cases, abnormal neurosonographic findings were identified including intracranial hemorrhage, brain atrophy, porencephaly and periventricular echogenicities evolving into polymicrogyria. Prenatal diagnosis of brain lesions was confirmed postnatally and all affected infants who survived had severe neurological sequelae. Two fetuses had normal cerebral structures both on the prenatal neurosonogram and on postnatal imaging and were following normal developmental milestones, one at 1 and the other at 5 years of age. In one case the neurosonographic examination was suboptimal and the infant was found at birth to have a porencephalic cyst. Fetal magnetic resonance imaging was performed in two cases and confirmed the ultrasound diagnosis., Conclusions: Prenatal neurosonography is a valuable tool for the prediction of neurological outcome in fetuses surviving after the intrauterine death of a monochorionic cotwin. Although our experience is limited, we suggest that magnetic resonance imaging should also be offered., (Copyright 2006 ISUOG)