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Objective The objectives of this study were as follows: (1) to investigate the accuracy of IVF identification on the prenatal screening record from prenatal screening laboratories; (2) to compare the screening markers in IVF and non-IVF pregnancies in the population of Ontario; and (3) to propose more appropriate IVF adjustment factors for the Ontario population. Methods Two years of IVF treatment, data from all fertility clinics in Ontario were merged with the corresponding prenatal screening data from all five prenatal screening labs. New adjustment factors for IVF were developed for each maternal serum screening marker and nuchal translucency measurement. Means and SDs and linear regression models were reported for all prenatal screening records, as well as for records that had IVF identified through the prenatal screening requisition and records that were identified through the Canadian Assisted Reproductive Technologies Register (CARTR) Plus database. Results Significant differences between IVF and non-IVF groups on the basis of the prenatal screening requisition information and CARTR Plus information were found among the ethnicity-adjusted mean multiple of the medians for alpha fetoprotein, first trimester pregnancy-associated plasma protein A, second trimester unconjugated estradiol, first trimester human chorionic gonadotropin, total human chorionic gonadotropin, and dimeric inhibin A. Conclusion This study proposed alternate IVF adjustment factors that will produce more accurate screening results within the population of Ontario.

Objective Noninvasive fetal rhesus D (RhD) blood group genotyping may prevent unnecessary use of anti-D immunoglobulin (RhIG) in non-alloimmunized RhD-negative pregnancies and can guide management of alloimmunized pregnancies. We conducted a systematic review of the economic literature to determine the cost-effectiveness of this intervention over usual care. Data Sources Systematic literature searches of bibliographic databases (Ovid MEDLINE, Embase, and Cochrane) until February 26, 2019, and auto-alerts until October 30, 2020, and of grey literature sources were performed to retrieve all English-language studies. Study Selection We included studies done in serologically confirmed non-alloimmunized or alloimmunized RhD-negative pregnancies, comparing costs and effectiveness of the intervention versus usual care. Data Extraction and Synthesis Two reviewers extracted data from the eligible studies and assessed their methodological quality (risk of bias) using the Quality of Health Economic Studies (QHES) and Drummond tools. We narratively synthesized findings. Our review included 8 economic studies that evaluated non-invasive fetal RhD genotyping followed by targeted RhIG prophylaxis in non-alloimmunized pregnancies. Five studies further considered a subsequent alloimmunized pregnancy. The cost-effectiveness of the intervention versus usual care (e.g., universal RhIG or prophylaxis conditional on results of paternal testing) for non-alloiummunized pregnancies was inconsistent. Two studies indicated greater benefits and lower costs for the intervention, and another 2 suggested a trade-off. In 4 studies, the intervention was less effective and costlier than alternatives. Three studies were determined to be of high quality by both tools. Two of these studies favoured the intervention, and one assessed benefits in quality-adjusted life-years. No study clearly examined the cost-effectiveness of repetitive use of fetal genotyping in multiple non-alloimmunized or alloimmunized pregnancies. The cost of genotyping was the most influential parameter. Conclusion The cost-effectiveness of noninvasive fetal RhD genotyping for non-alloimmunized pregnancies varies between studies. Potential savings from targeted management of alloimmunized pregnancies requires further research.

Objective To review the available prenatal screening options in light of the recent technical advances and to provide an update of previous guidelines in the field of prenatal screening. Intended Users Health care providers involved in prenatal screening, including general practitioners, obstetricians, midwives, maternal fetal medicine specialists, geneticists, and radiologists. Target Population All pregnant women receiving counselling and providing informed consent for prenatal screening. Evidence Published literature was retrieved through searches of Medline, PubMed, and the Cochrane Library in and prior to March 2016 using an appropriate controlled vocabulary (prenatal diagnosis, amniocentesis, chorionic villi sampling, non-invasive prenatal screening) and key words (prenatal screening, prenatal genetic counselling). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies written in English and published from January 1985 to May 2016. Searches were updated on a regular basis and incorporated in the guideline. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical speciality societies. Guideline update Evidence will be reviewed 5 years after publication to determine whether all or part of the guideline should be updated. However, if important new evidence is published prior to the 5-year cycle, the review process may be accelerated for a more rapid update of some recommendations.

Resume Objectif Fournir, aux professionnels de la sante des domaines de l'obstetrique et de la genetique, des lignes directrices et des recommandations en ce qui a trait au depistage / diagnostic prenatal et a la prise en charge obstetricale du dysraphisme spinal ouvert / ferme (DSOF) chez le fœtus. Options La presente analyse englobe les techniques de depistage / diagnostic prenatal qui sont actuellement utilisees aux fins de la detection du DSOF, y compris le depistage des concentrations seriques en alphafoetoproteines chez la mere, l'echographie, l'imagerie par resonance magnetique visant le fœtus et l'amniocentese. Issues Ameliorer le depistage / diagnostic prenatal et la prise en charge obstetricale du DSOF, tout en prenant en consideration les soins offerts a la patiente, l'efficacite, les couts et les interventions de soins. Resultats La litterature publiee a ete recuperee par l'intermediaire de recherches menees dans PubMed ou MEDLINE, CINAHL et The Cochrane Library en novembre 2013 au moyen d'un vocabulaire controle et de mots cles appropries (p. ex. « prenatal screening », « congenital anomalies », « neural tube defects », « alpha-fetoprotein », « ultrasound scan », « magnetic resonance imaging »). Les resultats ont ete restreints aux analyses systematiques, aux essais comparatifs randomises / essais cliniques comparatifs et aux etudes observationnelles publies en anglais entre 1977 et 2012. Les recherches ont ete mises a jour de facon reguliere et ont ete integrees a la directive clinique jusqu'au 30 novembre 2013. La litterature grise (non publiee) a ete identifiee par l'intermediaire de recherches menees dans les sites Web d'organismes s'interessant a l'evaluation des technologies dans le domaine de la sante et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et aupres de societes de specialite medicale nationales et internationales. Une enquete en ligne menee aupres des praticiens de la sante a egalement fait l'objet d'une analyse. Valeurs La qualite des resultats est evaluee au moyen des criteres decrits dans le rapport du Groupe d'etude canadien sur les soins de sante preventifs (Tableau). Avantages, desavantages et couts La presente analyse permettra aux professionnels de la sante de mieux comprendre les methodes de depistage prenatal du DSOF dont nous disposons a l'heure actuelle, ainsi que les avantages et les risques qui sont associes a chacune de ces methodes, pour assurer la prise de decisions factuelles en ce qui concerne le depistage, le diagnostic et la prise en charge obstetricale du DSOF.

To provide maternity care providers and their patients with current evidence-based guidelines for maternal risk/benefit counselling for a prenatally identified at-risk pregnancy that requires ultrasound-guided prenatal diagnostic procedures and/or techniques for a genetic diagnosis and for subsequent pregnancy management decisions on questions such as level of obstetrical care provider, antenatal surveillance, location of care and delivery, and continuation or termination of pregnancy. This guideline is limited to maternal risk/benefit counselling and pregnancy management decisions for women who require, or are considering, an invasive ultrasound-guided procedure or technique for prenatal diagnosis.Pregnant women identified as having an increased risk of a fetal genetic abnormality secondary to the process of established prenatal screening protocols (maternal serum±imaging, high-risk cell-free DNA results, abnormal diagnostic fetal imaging, or a positive family history of an inherited condition). These women may require or request counselling about pregnancy risks and benefits of an invasive ultrasound-guided procedure to determine the etiology, diagnosis, and/or pathology for the possible fetal anomaly or anomalies.Published literature was retrieved through searches of Medline, PubMed, and the Cochrane Library in and prior to June 2014 using an appropriate controlled vocabulary (prenatal diagnosis, amniocentesis, chorionic villi sampling, cordocentesis) and key words (prenatal screening, prenatal genetic counselling, post-procedural pregnancy loss rate). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies written in English and published from January 1985 to June 2014. Searches were updated on a regular basis and incorporated in the guideline to June 2014. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical speciality societies.The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). Health benefits, side effects, and risks: Patient informed consent, knowledge translation, genetic prenatal risk assessment, anxiety relief, anxiety creation, advocacy, understanding or limitation for fetal testing, pregnancy management choice, pregnancy complication or loss, timely and improved care for birth of a neonate with recognized morbidity. Recommendations 1. The health care provider should counsel the at-risk pregnant woman on the different levels of genetic fetal testing in order for her to have a clear understanding and expectation of the level of testing and type of results that are offered. (III-B) 2. As part of the informed consent process, the health care provider should review with the at-risk pregnant woman the risks and benefits of in utero genetic diagnostic techniques associated with fetal genetic testing options. (III-A) 3. During risk/benefit counselling, the health care provider should advise that the best estimate of the pregnancy loss rate related to: a.amniocentesis is 0.5% to 1.0% (range 0.17 to 1.53%) (I) b.chorionic villus sampling is 0.5% to 1.0% (I) and c.cordocentesis or percutaneous umbilical blood sampling is 1.3% for fetuses with no anomalies and 1.3% to 25% for fetuses with single or multiple anomalies or intrauterine growth restriction. (II-2A).

To provide updated information on the pre- and post-conception use of oral folic acid with or without a multivitamin/micronutrient supplement for the prevention of neural tube defects and other congenital anomalies. This will help physicians, midwives, nurses, and other health care workers to assist in the education of women about the proper use and dosage of folic acid/multivitamin supplementation before and during pregnancy.Published literature was retrieved through searches of PubMed, Medline, CINAHL, and the Cochrane Library in January 2011 using appropriate controlled vocabulary and key words (e.g., folic acid, prenatal multivitamins, folate sensitive birth defects, congenital anomaly risk reduction, pre-conception counselling). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English from 1985 and June 2014. Searches were updated on a regular basis and incorporated in the guideline to June 2014 Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. Costs, risks, and benefits: The financial costs are those of daily vitamin supplementation and eating a healthy folate-enriched diet. The risks are of a reported association of dietary folic acid supplementation with fetal epigenetic modifications and with an increased likelihood of a twin pregnancy. These associations may require consideration before initiating folic acid supplementation. The benefit of folic acid oral supplementation or dietary folate intake combined with a multivitamin/micronutrient supplement is an associated decrease in neural tube defects and perhaps in other specific birth defects and obstetrical complications.The quality of evidence in the document was rated using the criteria described in the Report of the Canadian Task Force on Preventative Health Care (Table 1). Summary Statement In Canada multivitamin tablets with folic acid are usually available in 3 formats: regular over-the-counter multivitamins with 0.4 to 0.6 mg folic acid, prenatal over-the-counter multivitamins with 1.0 mg folic acid, and prescription multivitamins with 5.0 mg folic acid. (III) Recommendations 1. Women should be advised to maintain a healthy folate-rich diet; however, folic acid/multivitamin supplementation is needed to achieve the red blood cell folate levels associated with maximal protection against neural tube defect. (III-A) 2. All women in the reproductive age group (12-45 years of age) who have preserved fertility (a pregnancy is possible) should be advised about the benefits of folic acid in a multivitamin supplementation during medical wellness visits (birth control renewal, Pap testing, yearly gynaecological examination) whether or not a pregnancy is contemplated. Because so many pregnancies are unplanned, this applies to all women who may become pregnant. (III-A) 3. Folic acid supplementation is unlikely to mask vitamin B12 deficiency (pernicious anemia). Investigations (examination or laboratory) are not required prior to initiating folic acid supplementation for women with a risk for primary or recurrent neural tube or other folic acid-sensitive congenital anomalies who are considering a pregnancy. It is recommended that folic acid be taken in a multivitamin including 2.6 ug/day of vitamin B12 to mitigate even theoretical concerns. (II-2A) 4. Women at HIGH RISK, for whom a folic acid dose greater than 1 mg is indicated, taking a multivitamin tablet containing folic acid, should be advised to follow the product label and not to take more than 1 daily dose of the multivitamin supplement. Additional tablets containing only folic acid should be taken to achieve the desired dose. (II-2A) 5. Women with a LOW RISK for a neural tube defect or other folic acid-sensitive congenital anomaly and a male partner with low risk require a diet of folate-rich foods and a daily oral multivitamin supplement containing 0.4 mg folic acid for at least 2 to 3 months before conception, throughout the pregnancy, and for 4 to 6 weeks postpartum or as long as breast-feeding continues. (II-2A) 6. Women with a MODERATE RISK for a neural tube defect or other folic acid-sensitive congenital anomaly or a male partner with moderate risk require a diet of folate-rich foods and daily oral supplementation with a multivitamin containing 1.0 mg folic acid, beginning at least 3 months before conception. Women should continue this regime until 12 weeks' gestational age. (1-A) From 12 weeks' gestational age, continuing through the pregnancy, and for 4 to 6 weeks postpartum or as long as breast-feeding continues, continued daily supplementation should consist of a multivitamin with 0.4 to 1.0 mg folic acid. (II-2A) 7. Women with an increased or HIGH RISK for a neural tube defect, a male partner with a personal history of neural tube defect, or history of a previous neural tube defect pregnancy in either partner require a diet of folate-rich foods and a daily oral supplement with 4.0 mg folic acid for at least 3 months before conception and until 12 weeks' gestational age. From 12 weeks' gestational age, continuing throughout the pregnancy, and for 4 to 6 weeks postpartum or as long as breast-feeding continues, continued daily supplementation should consist of a multivitamin with 0.4 to 1.0 mg folic acid. (I-A). The same dietary and supplementation regime should be followed if either partner has had a previous pregnancy with a neural tube defect. (II-2A).

Objective To update and review the techniques and indications of preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS). Options Discussion about the genetic and technical aspects of preimplantation reproductive techniques, particularly those using new cytogenetic technologies and embryo-stage biopsy. Outcomes Clinical outcomes of reproductive techniques following the use of PGD and PGS are included. This update does not discuss in detail the adverse outcomes that have been recorded in association with assisted reproductive technologies. Evidence Published literature was retrieved through searches of The Cochrane Library and Medline in April 2014 using appropriate controlled vocabulary (aneuploidy, blastocyst/physiology, genetic diseases, preimplantation diagnosis/methods, fertilization in vitro) and key words (e.g., preimplantation genetic diagnosis, preimplantation genetic screening, comprehensive chromosome screening, aCGH, SNP microarray, qPCR, and embryo selection). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies published from 1990 to April 2014. There were no language restrictions. Searches were updated on a regular basis and incorporated in the update to January 2015. Additional publications were identified from the bibliographies of retrieved articles. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. Values The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. (Table 1) Benefits, harms, and costs This update will educate readers about new preimplantation genetic concepts, directions, and technologies. The major harms and costs identified are those of assisted reproductive technologies. Summary Preimplantation genetic diagnosis is an alternative to prenatal diagnosis for the detection of genetic disorders in couples at risk of transmitting a genetic condition to their offspring. Preimplantation genetic screening is being proposed to improve the effectiveness of in vitro fertilization by screening for embryonic aneuploidy. Though FISH-based PGS showed adverse effects on IVF success, emerging evidence from new studies using comprehensive chromosome screening technology appears promising.

Objective To provide obstetrical and genetic health care practitioners with guidelines and recommendations for prenatal screening, diagnosis, and obstetrical management of fetal open and closed neural tube defects (OCNTD). Options This review includes prenatal screening and diagnostic techniques currently being used for the detection of OCNTD including maternal serum alpha fetoprotein screening, ultrasound, fetal magnetic resonance imaging, and amniocentesis. Outcomes To improve prenatal screening, diagnosis, and obstetrical management of OCNTD while taking into consideration patient care, efficacy, cost, and care procedures. Evidence Published literature was retrieved through searches of PubMed or MEDLINE, CINAHL, and The Cochrane Library in November, 2013, using appropriate controlled vocabulary and key words (e.g., prenatal screening, congenital anomalies, neural tube defects, alpha fetoprotein, ultrasound scan, magnetic resonance imaging). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English from 1977 to 2012. Searches were updated on a regular basis and incorporated in the guideline to November 30, 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. An online survey of health care practitioners was also reviewed. Values The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table). Benefits, harms, and costs This review will provide health care practitioners with a better understanding of the available prenatal screening methods for OCNTD and the benefits and risks associated with each technique to allow evidenced-based decisions on OCNTD screening, diagnosis, and obstetrical management.

Objective To review the risk of in utero infection through prenatal invasive procedures in women with hepatitis B, hepatitis C, and/or human immunodeficiency virus (HIV) infections. Outcomes Fetal and neonatal morbidity and mortality. Evidence Published literature was retrieved through searches of Medline, CINAHL, and the Cochrane Library using appropriate controlled vocabulary (amniocentesis, chorionic villus sampling, cordocentesis, fetal and neonatal infection) and key words (hepatitis B, hepatitis C, HIV). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies from 2002 to 2012 published in English or French. (Studies from 1966 to 2002 were previously reviewed in Clinical Practice Guideline No. 123.) Searches were updated on a regular basis and incorporated in the guideline to February 2014. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. Values The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table).

Objective To describe the current investigation and management of non-immune fetal hydrops, with a focus on treatable or recurring etiologies. Outcomes To provide better counselling and management in cases of prenatally diagnosed non-immune hydrops. Evidence Published literature was retrieved through searches of PubMed or MEDLINE, CINAHL, and The Cochrane Library in 2011 using key words (non-immune hydrops fetalis, fetal hydrops, fetal therapy, fetal metabolism). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, observational studies, and significant case reports. Additional publications were identified from the bibliographies of these articles. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to May 2012. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. Benefits, harms, and costs These guidelines educate readers about the causes of non-immune fetal hydrops and its prenatal counselling and management. It also provides a standardized approach to non-immune fetal hydrops, emphasizing the search for prenatally treatable conditions and recurrent genetic etiologies. Values The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).

This document has been developed to aid clinicians in counselling patients about prenatal screening and to provide assistance in counselling about both positive and negative screening results.

Objective To provide the physician with an overview of common genetic conditions that should be considered during a women's annual gynaecological assessment to determine the patient's risk or to initiate specific testing or referral to another subspecialty service, depending on personal or family history. Options This genetic information can be used for patient education and possible disease and/or mutation screening or diagnosis. Outcomes The use of this genetic information may allow improved risk-benefit assessment and management at the annual gynaecological examination. Evidence Studies published in English up to and including May 2010 were retrieved through searches of PubMed and the Cochrane Library, using appropriate controlled vocabulary (gynaecological diagnosis, genetic inheritance) and key words (genetic risk, genetic mutation, inheritance, family history, uterus, ovary, endometrial, vagina, colon, gastric, renal, breast, cardiac, thrombophilia, diabetes, epilepsy, leiomyomata uteri). Other literature sources were identified through searching the web sites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. Values The levels of evidence are not adequate for evidence-based recommendations to be made. Benefits, harms, and costs This committee opinion will enhance the use of new genetic knowledge and its application to the annual gynaecological care of women. Risk management and diagnostic opportunities for genetic gynaecological conditions will be improved. A more complete understanding of genetic conditions may increase anxiety and psychological stress for women and their families. Sponsors Society of Obstetricians and Gynaecologists of Canada.

To provide an overview of delayed child-bearing and to describe the implications for women and health care providers.Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome. This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices.Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age. Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section. This guideline provides a framework to address these issues.Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility). The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements. Data were extracted based on the aims, sample, authors, year, and results.The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).The Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS 1. Women who delay child-bearing are at increased risk of infertility. Prospective parents, especially women, should know that their fecundity and fertility begin to decline significantly after 32 years of age. Prospective parents should know that assisted reproductive technologies cannot guarantee a live birth or completely compensate for age-related decline in fertility. (II-2A) 2. A fertility evaluation should be initiated after 6 months of unprotected intercourse without conception in women 35 to 37 years of age, and earlier in women37 years of age. (II-2A) 3. Prospective parents should be informed that semen quality and male fertility deteriorate with advancing age and that the risk of genetic disorders in offspring increases. (II-2A) 4. Women ≥ 35 years of age should be offered screening for fetal aneuploidy and undergo a detailed second trimester ultrasound examination to look for significant fetal birth defects (particularly cardiac defects). (II-1A) 5. Delayed child-bearing is associated with increased obstetrical and perinatal complications. Care providers need to be aware of these complications and adjust obstetrical management protocols to ensure optimal maternal and perinatal outcomes. (II-2A) 6. All adults of reproductive age should be aware of the obstetrical and perinatal risks of advanced maternal age so they can make informed decisions about the timing of child-bearing. (II-2A) 7. Strategies to improve informed decision-making by prospective parents should be designed, implemented, and evaluated. These strategies should provide opportunity for adults to understand the potential medical, social, and economic consequences of child-bearing throughout the reproductive years. (III-B) 8. Barriers to healthy reproduction, including workplace policies, should be reviewed to optimize the likelihood of healthy pregnancies. (III-C).

Objective To summarize for obstetrical care providers the current literature on array genomic hybridization in prenatal diagnosis and to outline the recommendations of the Canadian College of Medical Geneticists regarding the use of this new technology with respect to prenatal diagnosis. Evidence PubMed and Medline were searched for articles published in English between 2004 and 2010, using the key words DNA QF-PCR, quantitative fluorescent polymerase chain reaction, fetal chromosomal abnormalities, prenatal diagnosis, array genomic hybridization, fetal structural anomalies, and copy number variants Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. Searches were updated on a regular basis, and articles were incorporated in the guideline to September 2011. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. Values The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). Recommendations 1.Array genomic hybridization is not recommended in pregnancies at low risk for a structural chromosomal abnormality; for example, advanced maternal age, positive maternal serum screen, previous trisomy, or the presence of "soft markers" on fetal ultrasound. (III-D) 2.Array genomic hybridization may be an appropriate diagnostic test in cases with fetal structural abnormalities detected on ultrasound or fetal magnetic resonance imaging; it could be done in lieu of a karyotype if rapid aneuploidy screening is negative and an appropriate turnaround time for results is assured. (II-2A) 3.Any pregnant woman who qualifies for microarray genomic hybridization testing should be seen in consultation by a medical geneticist before testing so that the benefits, limitations, and possible outcomes of the analysis can be discussed in detail. The difficulties of interpreting some copy number variants should also be discussed. This will allow couples to make an informed decision about whether or not they wish to pursue such prenatal testing. (III-A)

Objective To review the information on fetal and perinatal autopsies, the process of obtaining consent, and the alternative informationgathering options following a prenatal diagnosis of nonchromosomal malformations, and to assist clinicians in providing postnatal counselling regarding fetal diagnosis and recurrence risks. Outcomes To provide better counselling about fetal and perinatal autopsies for women and families who are dealing with a prenatally diagnosed non-chromosomal fetal anomaly. Evidence Published literature was retrieved through searches of PubMed or Medline, CINAHL, and The Cochrane Library in 2009 and 2010, using appropriate key words (fetal autopsy, postmortem, autopsy, perinatal postmortem examination, autopsy protocol, postmortem magnetic resonance imaging, autopsy consent, tissue retention, autopsy evaluation). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. Additional publications were identified from the bibliographies of these articles. There were no date or language restrictions. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. Benefits, harms, and costs This update educates readers about (1) the benefits of a fetal perinatal autopsy, (2) the consent process, and (3) the alternatives when the family declines autopsy. It also provides a standardized approach to fetal and perinatal autopsies, emphasizing pertinent additional sampling when indicated. Values The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).

To develop a Canadian consensus document on maternal screening for fetal aneuploidy (e.g., Down syndrome and trisomy 18) in singleton pregnancies.Pregnancy screening for fetal aneuploidy started in the mid 1960s, using maternal age as the screening test. New developments in maternal serum and ultrasound screening have made it possible to offer all pregnant patients a non-invasive screening test to assess their risk of having a fetus with aneuploidy to determine whether invasive prenatal diagnostic testing is necessary. This document reviews the options available for non-invasive screening and makes recommendations for Canadian patients and health care workers.To offer non-invasive screening for fetal aneuploidy (trisomy 13, 18, 21) to all pregnant women. Invasive prenatal diagnosis would be offered to women who screen above a set risk cut-off level on non-invasive screening or to pregnant women whose personal, obstetrical, or family history places them at increased risk. Currently available non-invasive screening options include maternal age combined with one of the following: (1) first trimester screening (nuchal translucency, maternal age, and maternal serum biochemical markers), (2) second trimester serum screening (maternal age and maternal serum biochemical markers), or (3) 2-step integrated screening, which includes first and second trimester serum screening with or without nuchal translucency (integrated prenatal screen, serum integrated prenatal screening, contingent, and sequential). These options are reviewed, and recommendations are made.Studies published between 1982 and 2009 were retrieved through searches of PubMed or Medline and CINAHL and the Cochrane Library, using appropriate controlled vocabulary and key words (aneuploidy, Down syndrome, trisomy, prenatal screening, genetic health risk, genetic health surveillance, prenatal diagnosis). Results were restricted to systematic reviews, randomized controlled trials, and relevant observational studies. There were no language restrictions. Searches were updated on a regular basis and incorporated in the guideline to August 2010. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. The previous Society of Obstetricians and Gynaecologists of Canada guidelines regarding prenatal screening were also reviewed in developing this clinical practice guideline.The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care.This guideline is intended to reduce the number of prenatal invasive procedures done when maternal age is the only indication. This will have the benefit of reducing the numbers of normal pregnancies lost because of complications of invasive procedures. Any screening test has an inherent false-positive rate, which may result in undue anxiety. It is not possible at this time to undertake a detailed cost-benefit analysis of the implementation of this guideline, since this would require health surveillance and research and health resources not presently available; however, these factors need to be evaluated in a prospective approach by provincial and territorial initiatives. RECOMMENDATIONS 1. All pregnant women in Canada, regardless of age, should be offered, through an informed counselling process, the option of a prenatal screening test for the most common clinically significant fetal aneuploidies in addition to a second trimester ultrasound for dating, assessment of fetal anatomy, and detection of multiples. (I-A) 2. Counselling must be non-directive and must respect a woman's right to accept or decline any or all of the testing or options offered at any point in the process. (III-A) 3. Maternal age alone is a poor minimum standard for prenatal screening for aneuploidy, and it should not be used a basis for recommending invasive testing when non-invasive prenatal screening for aneuploidy is available. (II-2A) 4. Invasive prenatal diagnosis for cytogenetic analysis should not be performed without multiple marker screening results except for women who are at increased risk of fetal aneuploidy (a) because of ultrasound findings, (b) because the pregnancy was conceived by in vitro fertilization with intracytoplasmic sperm injection, or (c) because the woman or her partner has a history of a previous child or fetus with a chromosomal abnormality or is a carrier of a chromosome rearrangement that increases the risk of having a fetus with a chromosomal abnormality. (II-2E) 5. At minimum, any prenatal screen offered to Canadian women who present for care in the first trimester should have a detection rate of 75% with no more than a 3% false-positive rate. The performance of the screen should be substantiated by annual audit. (III-B) 6. The minimum standard for women presenting in the second trimester should be a screen that has a detection rate of 75% with no more than a 5% false-positive rate. The performance of the screen should be substantiated by annual audit. (III-B) 7. First trimester nuchal translucency should be interpreted for risk assessment only when measured by sonographers or sonologists trained and accredited for this service and when there is ongoing quality assurance (II-2A), and it should not be offered as a screen without biochemical markers in singleton pregnancies. (I-E) 8. Evaluation of the fetal nasal bone in the first trimester should not be incorporated as a screen unless it is performed by sonographers or sonologists trained and accredited for this service and there is ongoing quality assurance. (II-2E) 9. For women who undertake first trimester screening, second trimester serum alpha fetoprotein screening and/or ultrasound examination is recommended to screen for open neural tube defects. (II-1A) 10. Timely referral and access is critical for women and should be facilitated to ensure women are able to undergo the type of screening test they have chosen as first trimester screening. The first steps of integrated screening (with or without nuchal translucency), contingent, or sequential screening are performed in an early and relatively narrow time window. (II-1A) 11. Ultrasound dating should be performed if menstrual or conception dating is unreliable. For any abnormal serum screen calculated on the basis of menstrual dating, an ultrasound should be done to confirm gestational age. (II-1A) 12. The presence or absence of soft markers or anomalies in the 18- to 20-week ultrasound can be used to modify the a priori risk of aneuploidy established by age or prior screening. (II-2B) 13. Information such as gestational dating, maternal weight, ethnicity, insulin-dependent diabetes mellitus, and use of assisted reproduction technologies should be provided to the laboratory to improve accuracy of testing. (II-2A) 14. Health care providers should be aware of the screening modalities available in their province or territory. (III-B) 15. A reliable system needs to be in place ensuring timely reporting of results. (III-C) 16. Screening programs should be implemented with resources that support audited screening and diagnostic laboratory services, ultrasound, genetic counselling services, patient and health care provider education, and high quality diagnostic testing, as well as resources for administration, annual clinical audit, and data management. In addition, there must be the flexibility and funding to adjust the program to new technology and protocols. (II-3B).

Objective To provide a Canadian consensus document with recommendations on prenatal screening for and diagnosis of fetal aneuploidy (e.g., Down syndrome and trisomy 18) in twin pregnancies.

Resume Objectif Analyser la litterature portant sur l'utilisation de l'echographie diagnostique dans la prise en charge des grossesses gemellaires. Formuler des recommandations quant a la meilleure facon d'utiliser l'echographie dans les cas de grossesse gemellaire. Issues Baisse des taux de mortalite et de morbidite perinatales, ainsi que des taux de morbidite neonatale a court et a long terme, dans les cas de grossesse gemellaire. Optimisation du recours a l'echographie dans les cas de grossesse gemellaire. Resultats La litterature publiee a ete recuperee par l'intermediaire de recherches menees dans PubMed et The Cochrane Library, en 2008 et en 2009, au moyen d'un vocabulaire controle (p. ex. « twin », « ultrasound », « cervix », « prematurity ») et de mots cles (p. ex. « acardiac », « twin », « reversed arterial perfusion », « twin-to-twin transfusion syndrome », « amniotic fluid ») adequats. Les resultats ont ete restreints aux analyses systematiques, aux essais comparatifs randomises / essais cliniques comparatifs et aux etudes observationnelles. Aucune restriction n'a ete imposee en matiere de date. Les etudes ont ete restreintes a celles qui disposaient d'un resume ou d'un texte en francais ou en anglais. Les recherches ont ete mises a jour de facon reguliere et integrees a la directive clinique jusqu'en septembre 2009. La litterature grise (non publiee) a ete identifiee par l'intermediaire de recherches menees dans les sites Web d'organismes s'interessant a l'evaluation des technologies dans le domaine de la sante et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et aupres de societes de specialite medicale nationales et internationales. Valeurs Les donnees recueillies ont ete analysees par le comite d'imagerie diagnostique de la Societe des obstetriciens et gynecologues du Canada, avec l'apport des membres du comite de medecine fœto-maternelle et du comite de genetique de la SOGC. Les recommandations ont ete formulees conformement aux lignes directrices elaborees par le Groupe d'etude canadien sur les soins de sante preventifs (Tableau 1). Avantages, desavantages et couts La facilitation et l'optimisation du recours a l'echographie dans les cas de grossesse gemellaire constituent les avantages auxquels l'on s'attend de la presente directive clinique.

Objective To give health care providers information about the genetic information that can be used as part of health surveillance for women undergoing a pre-conception evaluation for genetic risk assessment and possible genetic screening or testing. Options This genetic information can be used for patient education and possible prenatal testing. Outcomes The use of this genetic information may allow improved risk-benefit assessment for pre-conception counselling for individual patients and their families. Evidence PubMed or Medline and the Cochrane Database were searched in November 2009, using appropriate key words (preconception, genetic disease, maternal, family history, genetic health risk, genetic health surveillance, prenatal screening, prenatal diagnosis, birth defects, and teratogen). Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, and national and international medical specialty societies. Benefits, harms, and costs The benefits for the patient and her family include understanding of possible genetic risk and enhanced pregnancy outcomes. The harm includes increased anxiety or psychological stress associated with the possibility of identifying genetic risks. Validation The evidence obtained was reviewed by the Genetics Committee of the Society of Obstetricians and Gynaecologists of Canada.

Resume Objectif Offrir aux fournisseurs de soins de sante des renseignements au sujet des donnees genetiques qui peuvent etre utilisees dans le cadre de la surveillance de la sante pour les femmes qui subissent une evaluation preconceptionnelle visant a determiner le risque genetique et la possibilite de proceder a un depistage ou a des tests genetiques. Options Ces donnees genetiques peuvent etre utilisees aux fins de la sensibilisation des patientes et du depistage prenatal potentiel. Issues L'utilisation de ces donnees genetiques pourrait permettre l'amelioration de l'evaluation des risques et des avantages pour ce qui est du counseling preconceptionnel a l'intention des patientes et de leur famille. Resultats Des recherches ont ete menees dans PubMed ou Medline et la base de donnees Cochrane en novembre 2009, au moyen de mots cles appropries (« pre-conception », « genetic disease », « maternal, family history », « genetic health risk », « genetic health surveillance », « prenatal screening », « prenatal diagnosis », « birth defects » et « teratogen »). La litterature grise (non publiee) a ete identifiee par l'intermediaire de recherches menees dans les sites Web d'organismes s'interessant a l'evaluation des technologies dans le domaine de la sante et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et aupres de societes de specialite medicale nationales et internationales. Avantages, desavantages et couts Parmi les avantages pour la patiente et sa famille, on trouve la comprehension d'un possible risque genetique et l'obtention de meilleures issues de grossesse. Parmi les desavantages, on trouve une hausse de l'anxiete ou du stress psychologique associe a la possibilite d'identifier des risques genetiques. Validation Les resultats obtenus ont ete analyses par le comite de genetique de la Societe des obstetriciens et gynecologues du Canada.

Resume Objectif Analyser les donnees au sujet des autopsies foetales et perinatales, le processus d'obtention du consentement et les autres options de collecte de donnees a la suite d'un diagnostic prenatal de malformations non chromosomiques, ainsi qu'aider les cliniciens a offrir des services de counseling postnatal a propos du diagnostic foetal et des risques de recurrence.Criteres d'evaluation des resultats et de classifcation des recommandations, fondes sur ceux du Groupe d'etude canadien sur les soins de sante preventifsNiveaux de resultats*Categories de recommandations† I:Resultats obtenus dans le cadre d'au moins un essai comparatif convenablement randomise II-1:Resultats obtenus dans le cadre d'essais comparatifs non randomises bien concus II-2:Resultats obtenus dans le cadre d'etudes de cohortes (prospectives ou retrospectives) ou d'etudes analytiques cas-temoins bien concues, realisees de preference dans plus d'un centre ou par plus d'un groupe de recherche II-3:Resultats decoulant de comparaisons entre differents moments ou differents lieux, ou selon qu'on a ou non recours a une intervention Des resultats de premiere importance obtenus dans le cadre d'etudes non comparatives (par exemple, les resultats du traitement a la penicilline, dans les annees 1940) pourraient en outre fgurer dans cette categorie III:Opinions exprimees par des sommites dans le domaine, fondees sur l'experience clinique, etudes descriptives ou rapports de comites d'experts A.On dispose de donnees suffsantes pour appuyer la mesure clinique de prevention B.On dispose de donnees acceptables pour appuyer la mesure clinique de prevention C.Les donnees existantes sont contradictoires et ne permettent pas de formuler une recommandation pour ou contre l'usage de la mesure clinique de prevention; cependant, d'autres facteurs peuvent infuer sur la prise de decision D.On dispose de donnees acceptables pour deconseiller la mesure clinique de prevention E.On dispose de donnees suffsantes pour deconseiller la mesure clinique de prevention F.Les donnees sont insuffsantes (d'un point de vue qantitatif ou qualitatif) et ne permettent pas de formuler une recommandation; cependant, d'autres facteurs peuvent infuer sur la prise de decision Woolf SH, Battista RN, Angerson GM, Logan AG, Eel W « Canadian Task Force on Preventive Health Care New grades for recommendations from the Canadian Task Force on Preventive Health Care », CMAJ, vol 169, 2003, p 207–8*La qualite des resultats signales dans les presentes directives cliniques a ete etablie conformement aux criteres d'evaluation des resultats presentes dans le Rapport du Groupe d'etude canadien sur les soins de sante preventifs†Les recommandations que comprennent les presentes directives cliniques ont ete classees conformement a la methode de classifcation decrite dans le Rapport du Groupe d'etude canadien sur les soins de sante preventif Issues Mieux conseiller les patientes et leur famille qui font face a un diagnostic prenatal d'anomalie foetale non chromosomique au sujet des autopsies foetales et perinatales. Resultats La litterature publiee a ete recuperee par l'intermediaire de recherches menees dans PubMed ou MEDLINE, CINAHL et The Cochrane Library en 2009 et en 2010, au moyen de mots cles adequats (« fetal autopsy », « postmortem », « autopsy », « perinatal postmortem examination », « autopsy protocol », « postmortem magnetic resonance imaging », « autopsy consent », « tissue retention », « autopsy evaluation »). Les resultats ont ete restreints aux analyses systematiques, aux essais comparatifs randomises / essais cliniques comparatifs et aux etudes observationnelles. Des publications additionnelles ont ete identifiees a partir des bibliographies de ces articles. Aucune restriction n'a ete imposee en matiere de date ou de langue. La litterature grise (non publiee) a ete identifiee par l'intermediaire de recherches menees dans les sites Web d'organismes s'interessant a l'evaluation des technologies dans le domaine de la sante et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et aupres de societes de specialite medicale nationales et internationales. Avantages, desavantages et couts La presente mise a jour renseigne les lecteurs au sujet (1) des avantages de la tenue d'une autopsie foetale ou perinatale, (2) du processus de consentement et (3) des solutions de rechange face au refus de la famille de proceder a une autopsie. Elle offre egalement une approche standardisee envers les autopsies foetales et perinatales, en mettant l'accent sur les prelevements additionnels pertinents, le cas echeant. Valeurs La qualite des resultats a ete evaluee au moyen des criteres decrits dans le rapport du Groupe d'etude canadien sur les soins de sante preventifs (Tableau 1).

Resume Objectif Offrir aux fournisseurs de soins de sante canadiens des donnees actuelles sur l'utilisation de l'amplification en chaine par polymerase fluorescente quantitative (QF-PCR) ou d'une technologie equivalente dans le diagnostic prenatal des anomalies chromosomiques fœtales. Options Au cours des dernieres decennies, le diagnostic prenatal des anomalies chromosomiques fœtales a repose sur l'analyse cytogenetique conventionnelle de cultures d'amniocytes, de villosites choriales ou de sang fœtal. Au cours des quelques dernieres annees, la validite clinique d'une nouvelle technique (la QF-PCR) pour ce qui est de la detection des aneuploidies courantes a ete signalee par un certain nombre de chercheurs. Cette technique dispose de l'avantage de fournir rapidement des resultats pour le diagnostic ou l'exclusion de l'aneuploidie en ce qui concerne les chromosomes 13, 18, 21, X ou Y II est maintenant possible de choisir d'avoir recours a une analyse chromosomique standard ou a la QF-PCR pour le diagnostic prenatal des anomalies chromosomiques (ou encore de mener ces deux tests), en fonction de l'indication clinique du depistage. Le present document analyse l'utilite clinique de la QF-PCR et formule des recommandations quant a son utilisation dans le cadre des soins offerts aux patientes canadiennes. Resultats Des recherches ont ete menees dans Medline et PubMed afin d'en tirer les articles publies en anglais entre janvier 2000 et decembre 2010 qui presentaient des donnees issues de la comparaison entre la QF-PCR et l'analyse cytogenetique standard des prelevements prenataux. Une deuxieme recherche a ete menee pour identifier les publications en anglais qui offraient des resultats d'analyses cytogenetiques menees sur des prelevements prenataux chez des femmes exposees a un risque accru d'aneuploidie fœtale en raison de leur âge, de resultats anormaux a la suite du depistage prenatal ou de marqueurs faibles echographiques fœtaux semblant indiquer un risque accru d'aneuploidie. Ces publications ont ete incluses lorsqu'elles offraient des renseignements detailles sur les anomalies detectees, peu importe si un depistage rapide de l'aneuploidie avait ete mene. Les resultats ont ete restreints aux analyses systematiques, aux essais comparatifs randomises et aux etudes observationnelles pertinentes. La litterature grise (non publiee) a ete identifiee par l'intermediaire de recherches menees dans les sites Web d'organismes s'interessant a l'evaluation des technologies dans le domaine de la sante et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et aupres de societes de specialite medicale nationales et internationales. Les directives cliniques precedemment publiees par la Societe des obstetriciens et gynecologues du Canada au sujet du depistage prenatal ont egalement ete analysees dans le cadre de l'elaboration de la presente directive clinique. Valeurs La qualite des resultats a ete evaluee au moyen des criteres decrits dans le rapport du Groupe d'etude canadien sur les soins de sante preventifs (Tableau). Avantages, desavantages et couts La presente directive clinique fait la promotion du recours a un test ADN rapide de depistage de l'aneuploidie chez les femmes exposees a un risque accru de connaitre une grossesse affectee par une aneuploidie courante. La mise en oeuvre d'un tel test aura l'avantage de fournir rapidement des resultats precis aux femmes exposees a un risque accru de syndrome de Down, de trisomie 13, de trisomie 18, d'aneuploidie ou de triploidie des chromosomes sexuels. Elle favorisera egalement une meilleure utilisation des ressources laboratoires et la reduction des couts lies au diagnostic prenatal. Cependant, un faible pourcentage de grossesses presentant une anomalie chromosomique potentiellement significative sur le plan clinique, bien que detectables au moyen de methodes cytogenetiques conventionnelles, passeront inapercues au moment de la mise en oeuvre de la QF-PCR. Recommandations 1. La QF-PCR est un moyen fiable de detecter les trisomies et devrait remplacer l'analyse cytogenetique conventionnelle lorsque le depistage prenatal n'est mene qu'en raison d'un risque accru d'aneuploidie affectant les chromosomes 13, 18, 21, X ou Y. Comme pour tout autre test, les services de counseling pretest devraient comprendre une discussion sur les avantages et les limites de ce test. Au cours de la periode initiale d'utilisation, l'offre d'une formation aux fournisseurs de soins de sante s'averera necessaire. (II-2A) 2. L'analyse cytogenetique conventionnelle et la QF-PCR devraient toutes deux etre mises en oeuvre dans tous les cas de diagnostic prenatal demande en raison de la constatation echographique d'une anomalie foetale (y compris une mesure accrue de la clarte nucale > 3,5 mm) ou de la presence d'un remaniement chromosomique familial. (II-2A) 3. Le suivi cytogenetique des resultats de QF-PCR indiquant des trisomies 13 et 21 est recommande pour ecarter la presence possible de translocations robertsoniennes hereditaires. Toutefois, la decision de mettre en oeuvre, pour tous les cas, une culture d'appoint qui permettrait la tenue d'un depistage cytogenetique traditionnel (lorsque cela s'avererait indique en raison de donnees cliniques ou de laboratoire additionnelles) devrait etre prise par chacun des centres offrant le depistage, en fonction de l'experience et des ressources cliniques et de laboratoire locales. (III-A) 4. D'autres technologies de detection rapide de l'aneuploidie etant en mesure d'offrir un rendement semblable ou ameliore (pour ce qui est de la detection des trisomies 13, 18 et 21, et de l'aneuploidie des chromosomes sexuels) pourraient en venir a remplacer la QF-PCR. (III-A)

Resume Objectif Offrir aux fournisseurs de soins de maternite et a leurs patientes des lignes directrices factuelles contemporaines en ce qui concerne les services de counseling traitant des risques et des avantages maternels propres a la tenue des interventions diagnostiques prenatales orientees par echographie (et/ou des techniques permettant l'etablissement d'un diagnostic genetique) necessaires dans les cas ou il a ete etabli pendant la periode prenatale que la grossesse serait exposee a des risques, ainsi qu'en ce qui concerne la prise de decisions subsequentes quant a la prise en charge de la grossesse (questions abordant des aspects tels que le niveau du fournisseur de soins obstetricaux, la surveillance prenatale, le lieu ou devraient se derouler les soins et l'accouchement, et la decision de poursuivre ou d'interrompre la grossesse). La presente directive clinique se limite aux services de counseling traitant des risques et des avantages maternels, et aux decisions en matiere de prise en charge de la grossesse pour les femmes qui necessitent (ou qui envisagent) la mise en oeuvre d'une intervention ou d'une technique effractive orientee par echographie aux fins de l'etablissement d'un diagnostic prenatal. Population de patientes Femmes enceintes identifiees, a la suite de la mise en oeuvre de protocoles etablis de depistage prenatal (taux seriques maternels ± imagerie, resultats d'analyse de l'ADN acellulaire indiquant des risques eleves, resultats anormaux au moment de l'imagerie foetale diagnostique ou antecedents familiaux de troubles hereditaires), comme etant exposees a un risque accru d'anomalie genetique foetale. Ces femmes pourraient necessiter ou demander des services de counseling au sujet des risques et des avantages pour la grossesse de la tenue d'une intervention effractive orientee par echographie visant a determiner l'etiologie, le diagnostic, et/ou la pathologie de possibles anomalies foetales.

Resume Objectif Analyser le risque d'infection in utero attribuable aux interventions effractives prenatales chez les femmes qui presentent des infections par le virus de l'hepatite B, le virus de l'hepatite C et/ou le virus de l'immunodeficience humaine (VIH). Issues Morbidite et mortalite foetales et neonatales. Resultats La litterature publiee a ete recuperee par l'intermediaire de recherches menees dans Medline, CINAHL et The Cochrane Library au moyen d'un vocabulaire controle (p. ex. « amniocentesis », « chorionic villus sampling », « cordocentesis », « fetal and neonatal infection ») et de mots cles (p. ex. « hepatitis B », « hepatitis C », « HIV ») appropries. Les resultats ont ete restreints aux analyses systematiques, aux essais comparatifs randomises / essais cliniques comparatifs et aux etudes observationnelles publies en anglais ou en francais entre 2002 et 2012 (les etudes publiees entre 1966 et 2002 ont deja fait l'objet d'une analyse dans le cadre de la directive clinique n° 123). Les recherches ont ete mises a jour de facon reguliere et integrees a la directive clinique jusqu'en fevrier 2014. La litterature grise (non publiee) a ete identifiee par l'intermediaire de recherches menees dans les sites Web d'organismes s'interessant a l'evaluation des technologies dans le domaine de la sante et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et aupres de societes de specialite medicale nationales et internationales. Valeurs La qualite des resultats est evaluee au moyen des criteres decrits dans le rapport du Groupe d'etude canadien sur les soins de sante preventifs (Tableau). Recommandations 1.Pour l'evaluation du risque prenatal chez les femmes infectees par le virus de l'hepatite B, le virus de l'hepatite C et/ou le virus de l'immunodeficience humaine, il est recommande d'utiliser des methodes non effractives qui font appel a des tests comptant une sensibilite elevee et un faible taux de faux positif (comme le depistage serique combine [ou non] a la mesure de la clarte nucale, l'echographie anatomique et le depistage prenatal moleculaire non effractif). (III-B) 2.Dans le cas des femmes infectees par le virus de l'hepatite B, le virus de l'hepatite C et/ou le virus de l'immunodeficience humaine qui doivent subir une amniocentese, aucun effort ne devrait etre menage pour faire en sorte d'eviter d'inserer l'aiguille au travers du placenta ou tres pres de ce dernier. (II-2B) 3.Nous ne disposons que de peu de donnees au sujet des autres interventions effractives prenatales diagnostiques et therapeutiques; nous devrions donc proceder a l'analyse des risques et des avantages de telles interventions avant de les utiliser. (III-C) 4.Le taux d'infection neonatale par le virus de l'hepatite B qui est attribuable a l'amniocentese peut atteindre jusqu'a 1,4 % chez les nouveau-nes issus de meres seropositives pour l'antigene de surface de l'hepatite B. Toutefois, le taux d'infection neonatale attribuable a l'amniocentese chez les nouveau-nes issus de meres seropositives pour l'antigene e de l'hepatite B pourrait atteindre pas moins de 16 %. Bien que l'on n'ait constate aucune difference significative sur le plan statistique en matiere de taux d'infection entre les nouveau-nes exposes a l'amniocentese et ceux qui ne l'ont pas ete, au sein de ces deux populations maternelles, le fait de connaitre l'etat serologique de la mere quant a l'antigene e de l'hepatite B pourrait se reveler utile au moment de lui offrir des renseignements au sujet des risques associes a l'amniocentese. (II-2A) 5.Chez les femmes infectees par le virus de l'hepatite C, la tenue d'une amniocentese ne semble pas entrainer une hausse significative du risque de transmission verticale; quoi qu'il en soit, les femmes devraient etre avisees que tres peu d'etudes se sont adequatement penchees sur une telle possibilite. (II-2C) La tenue d'autres recherches a ce sujet est recommandee. (III-L) 6.Chez les femmes infectees par le virus de l'immunodeficience humaine qui font l'objet d'un traitement antiretroviral combine, l'amniocentese ne semble pas entrainer une hausse significative du risque de transmission verticale, particulierement lorsque la charge virale est indetectable; quoi qu'il en soit, les femmes devraient etre avisees que nous ne disposons que de peu de donnees sur le sujet. (II-2B) 7.Chez les femmes qui ne font pas l'objet d'un traitement antiretroviral combine, la tenue d'une amniocentese entraine la hausse du risque de transmission verticale. Dans la mesure du possible, l'administration d'un traitement antiretroviral combine devrait etre entamee et la tenue de l'amniocentese devrait etre differee jusqu'a ce que la charge virale devienne indetectable. Les autres aspects de la prise en charge devraient etre personnalises en consultation avec des specialistes en maladies infectieuses et des obstetriciens. (III-B)

Resume Objectif Fournir une analyse des etudes publiees sur l'utilisation de l'ADN fœtal acellulaire se trouvant dans le plasma maternel aux fins du diagnostic non effractif du syndrome de Down, de la trisomie 18 et de la trisomie 13. Resultats: Des recherches ont ete menees dans PubMed en vue d'en tirer des articles publies entre 2006 et octobre 2012, au moyen de mots cles appropries (p. ex. « non-invasive prenatal diagnosis », « Down syndrome », « cell-free fetal DNA », « aneuploidy screening »). Les resultats ont ete restreints aux analyses systematiques, aux essais comparatifs randomises / essais cliniques comparatifs et aux etudes observationnelles. Les recherches ont ete mises a jour de facon reguliere et integrees a la directive clinique jusqu'au 31 octobre 2012. La litterature grise (non publiee) a ete identifiee par l'intermediaire de recherches menees dans les sites Web d'organismes s'interessant a l'evaluation des technologies dans le domaine de la sante et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et aupres de societes de specialite medicale nationales et internationales. Valeurs Les etudes analysees ont ete classees conformement aux criteres decrits par le Groupe d'etude canadien sur les soins de sante preventifs et les recommandations visant la pratique ont ete evaluees en fonction de cette classification (Tableau).

Resume Le present document a ete redige pour aider les cliniciens a conseiller leurs patientes au sujet du depistage prenatal et pour les aider a traiter des resultats tant positifs que negatifs de ce depistage.