title: Prevalence of congenital anomalies at birth among offspring of women at risk for a genetic disorder and with a normal second-trimester ultrasound.
abstract: The goal of this study was to determine the prevalence and the nature of congenital anomalies found at birth in offspring of women who had a normal second-trimester ultrasound and/or amniocentesis. Two groups of women were studied in our prenatal diagnosis clinic between 1991-1997. Group 1 consisted of pregnant women who had an amniocentesis for advanced maternal age (AMA), or for familial chromosomal or monogenic disorders. Group 2 consisted of pregnant women attending the prenatal diagnosis clinic and who had no indication for amniocentesis. Those with an abnormal ultrasound and/or amniocentesis were excluded. At the time of delivery, a questionnaire was sent pertaining to perinatal complications and the anomalies detected during the neonatal period. From a total of 15, 370 questionnaires sent from 1991-1997, 10,823 (group 1, n = 8,877; group 2, n = 1,946) were returned (overall response rate, 70.4%). Mean maternal age was 36 years in group 1 and 29 years in group 2. The prevalence of perinatal complications was similar in the two groups. In each group, the prevalence of all unforeseen anomalies was 2.9%. In group 1, the distribution of those anomalies was: major anomalies, 67.7%; minor anomalies, 23.9%; and multiple congenital anomalies (MCA), 8.3%. In group 2, the distribution was: major anomalies, 70.7%; minor anomalies, 24.1%; and MCA, 5.2%. In patients at risk for a genetic disease and consulting in a prenatal diagnosis clinic, the prevalence of all anomalies diagnosed at birth was 2.9%, even if the second-trimester ultrasound and amniocentesis results were normal. Therefore, it is important to inform those couples of this remaining risk.
authors.affiliation: Service de Génétique Médicale, Département de Pédiatrie, Hôpital Sainte-Justine, Université de Montréal, Montreal, Quebec, H3T 1C5 Canada.
authors.forename: E
authors.initials: E
authors.lastname: Lemyre
authors.forename: C
authors.initials: C
authors.lastname: Infante-Rivard
authors.forename: L
authors.initials: L
authors.lastname: Dallaire
mesh_terms: D000015:Abnormalities, Multiple / Q000145:classification / Q000196:embryology / Q000453:epidemiology*; D000328:Adult; D000649:Amniocentesis; D002170:Canada / Q000453:epidemiology; D000013:Congenital Abnormalities / Q000145:classification / Q000196:embryology / Q000453:epidemiology*; D005260:Female; D005313:Fetal Death; D030342:Genetic Diseases, Inborn / Q000453:epidemiology* / Q000235:genetics; D006801:Humans; D007231:Infant, Newborn; D008423:Maternal Age; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk; D015995:Prevalence; D012016:Reference Values; D012307:Risk Factors; D016216:Ultrasonography, Prenatal