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Objectives: To assess the diagnostic accuracy of two‐dimensional ultrasound at 11–14 weeks' gestation as a screening test for individual fetal anomalies and to identify factors impacting on screening performance. Methods: This was a systematic review and meta‐analysis that was developed and registered with PROSPERO (CRD42018111781). MEDLINE, EMBASE, Web of Science Core Collection and the Cochrane Library were searched for studies evaluating the diagnostic accuracy of screening for 16 predefined, non‐cardiac, congenital anomalies considered to be of interest to the early anomaly scan. We included prospective and retrospective studies from any healthcare setting conducted in low‐risk, mixed‐risk and unselected populations. The reference standard was the detection of an anomaly on postnatal or postmortem examination. Data were extracted to populate 2 × 2 tables and a random‐effects model was used to determine the diagnostic accuracy of screening for the predefined anomalies (individually and as a composite). Secondary analyses were performed to determine the impact on detection rates of imaging protocol, type of ultrasound modality, publication year and index of sonographer suspicion at the time of scanning. Post‐hoc secondary analysis was conducted to assess performance among studies published during or after 2010. Risk of bias assessment and quality assessment were undertaken for included studies using the Quality Assessment of Diagnostic Accuracy Studies‐2 tool. Results: From 5684 citations, 202 papers underwent full‐text review, resulting in the inclusion of 52 studies comprising 527 837 fetuses, of which 2399 were affected by one or more of the 16 predefined anomalies. Individual anomalies were not equally amenable to detection on first‐trimester ultrasound: a high (> 80%) detection rate was reported for severe conditions, including acrania (98%), gastroschisis (96%), exomphalos (95%) and holoprosencephaly (88%); the detection rate was lower for open spina bifida (69%), lower urinary tract obstruction (66%), lethal skeletal dysplasias (57%) and limb‐reduction defects (50%); and the detection rate was below 50% for facial clefts (43%), polydactyly (40%) and congenital diaphragmatic hernia (38%). Conditions with a low (< 30%) detection rate included bilateral renal agenesis (25%), closed spina bifida (21%), isolated cleft lip (14%) and talipes (11%). Specificity was > 99% for all anomalies. Secondary analysis showed that detection improved with advancing publication year, and that the use of imaging protocols had a statistically significant impact on screening performance (P < 0.0001). Conclusions: The accurate detection of congenital anomalies using first‐trimester ultrasound is feasible, although detection rates and false‐positive rates depend on the type of anomaly. The use of a standardized protocol allows for diagnostic performance to be maximized, particularly for the detection of spina bifida, facial clefts and limb‐reduction defects. Highlighting the types of anomalies amenable to diagnosis and determining factors enhancing screening performance can support the development of first‐trimester anomaly screening programs. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Objectives: To determine the diagnostic accuracy of ultrasound at 11-14 weeks' gestation in the detection of fetal cardiac abnormalities and to evaluate factors that impact the detection rate.Methods: This was a systematic review of studies evaluating the diagnostic accuracy of ultrasound in the detection of fetal cardiac anomalies at 11-14 weeks' gestation, performed by two independent reviewers. An electronic search of four databases (MEDLINE, EMBASE, Web of Science Core Collection and The Cochrane Library) was conducted for studies published between January 1998 and July 2020. Prospective and retrospective studies evaluating pregnancies at any prior level of risk and in any healthcare setting were eligible for inclusion. The reference standard used was the detection of a cardiac abnormality on postnatal or postmortem examination. Data were extracted from the included studies to populate 2 × 2 tables. Meta-analysis was performed using a random-effects model in order to determine the performance of first-trimester ultrasound in the detection of major cardiac abnormalities overall and of individual types of cardiac abnormality. Data were analyzed separately for high-risk and non-high-risk populations. Preplanned secondary analyses were conducted in order to assess factors that may impact screening performance, including the imaging protocol used for cardiac assessment (including the use of color-flow Doppler), ultrasound modality, year of publication and the index of sonographer suspicion at the time of the scan. Risk of bias and quality assessment were undertaken for all included studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.Results: The electronic search yielded 4108 citations. Following review of titles and abstracts, 223 publications underwent full-text review, of which 63 studies, reporting on 328 262 fetuses, were selected for inclusion in the meta-analysis. In the non-high-risk population (45 studies, 306 872 fetuses), 1445 major cardiac anomalies were identified (prevalence, 0.41% (95% CI, 0.39-0.43%)). Of these, 767 were detected on first-trimester ultrasound examination of the heart and 678 were not detected. First-trimester ultrasound had a pooled sensitivity of 55.80% (95% CI, 45.87-65.50%), specificity of 99.98% (95% CI, 99.97-99.99%) and positive predictive value of 94.85% (95% CI, 91.63-97.32%) in the non-high-risk population. The cases diagnosed in the first trimester represented 63.67% (95% CI, 54.35-72.49%) of all antenatally diagnosed major cardiac abnormalities in the non-high-risk population. In the high-risk population (18 studies, 21 390 fetuses), 480 major cardiac anomalies were identified (prevalence, 1.36% (95% CI, 1.20-1.52%)). Of these, 338 were detected on first-trimester ultrasound examination and 142 were not detected. First-trimester ultrasound had a pooled sensitivity of 67.74% (95% CI, 55.25-79.06%), specificity of 99.75% (95% CI, 99.47-99.92%) and positive predictive value of 94.22% (95% CI, 90.22-97.22%) in the high-risk population. The cases diagnosed in the first trimester represented 79.86% (95% CI, 69.89-88.25%) of all antenatally diagnosed major cardiac abnormalities in the high-risk population. The imaging protocol used for examination was found to have an important impact on screening performance in both populations (P < 0.0001), with a significantly higher detection rate observed in studies using at least one outflow-tract view or color-flow Doppler imaging (both P < 0.0001). Different types of cardiac anomaly were not equally amenable to detection on first-trimester ultrasound.Conclusions: First-trimester ultrasound examination of the fetal heart allows identification of over half of fetuses affected by major cardiac pathology. Future first-trimester screening programs should follow structured anatomical assessment protocols and consider the introduction of outflow-tract views and color-flow Doppler imaging, as this would improve detection rates of fetal cardiac pathology. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]