Congenital anomalies associated with trisomy 18 or trisomy 13: A registry-based study in 16 European countries, 2000-2011.

The aim of this study was to examine the prevalence of trisomies 18 and 13 in Europe and the prevalence of associated anomalies. Twenty-five population-based registries in 16 European countries provided data from 2000-2011. Cases included live births, fetal deaths (20+ weeks' gestation), and terminations of pregnancy for fetal anomaly (TOPFAs). The prevalence of associated anomalies was reported in live births. The prevalence of trisomy 18 and trisomy 13 were 4.8 (95%CI: 4.7-5.0) and 1.9 (95%CI: 1.8-2.0) per 10,000 total births. Seventy three percent of cases with trisomy 18 or trisomy 13 resulted in a TOPFA. Amongst 468 live born babies with trisomy 18, 80% (76-83%) had a cardiac anomaly, 21% (17-25%) had a nervous system anomaly, 8% (6-11%) had esophageal atresia and 10% (8-13%) had an orofacial cleft. Amongst 240 Live born babies with trisomy 13, 57% (51-64%) had a cardiac anomaly, 39% (33-46%) had a nervous system anomaly, 30% (24-36%) had an eye anomaly, 44% (37-50%) had polydactyly and 45% (39-52%) had an orofacial cleft. For babies with trisomy 18 boys were less likely to have a cardiac anomaly compared with girls (OR = 0.48 (0.30-0.77) and with trisomy 13 were less likely to have a nervous system anomaly [OR = 0.46 (0.27-0.77)]. Babies with trisomy 18 or trisomy 13 do have a high proportion of associated anomalies with the distribution of anomalies being different in boys and girls.