Congenital Anomalies in Singapore

Abstract A 3‐year study (Jan. 1986‐Dec. 1988) in the Kandang Kerbau Hospital revealed 678 infants with birth defects in 44,842 livebirths, (15.13 per 1,000 live births, 95% confidence intervals, CI 14.0–16.2). There were 161 cases with musculoskeletal abnormalities (3.5 per 1,000, 95% CI 3.06‐4.19), 111 gastrointestinal system malformations (2.47 per 1,000, 95% CI 2.04‐2.58), 88 chromosomal abnormalities (1.96 per 1,000, 95% CI 1.57‐2.42), 78 cardiovascular system abnormalities (1.74 per 1,000, 95% CI 1.38‐2.17), 73 urogenital system defects (1.63 per 1,000, 95% CI 1.28‐2.05), and 52 central nervous system defects (1.16 per 1,000, 95% CI 0.87‐1.52). The prevalence of cleft lip, cleft palate, and cleft lip/palate was 1.72 per 1,000, and Down's Syndrome 1 in 700. At review, six weeks later, the false positive rate was 4% in the infants with defects, and in the group of 709 normal controls (matched by race, maternal age, ward class and time/date of birth), the false negative rate was 0.84%.The strongest risk factors were a family history of birth defects (odds ratio, OR 3.3, 95% CI 1.8‐6.4), and previous abnormal sibling(s) (OR 2.4, 95% CI 1.1–5.3). Other risk factors included drug intake during pregnancy (OR 1.2, 95% CI 0.8‐2.0), becoming significant with ingestion during the first trimester (OR 1.4, 95% CI 1.1‐1.8). Traditional medicine (mainly Chinese herbs during pregnancy) had a slightly higher risk (OR 1.4, 95% CI 1.0–2.0).The National University Hospital keeps a register of birth defects; trained nurses interview all mothers using a set questionnaire. Evaluation of 11,460 livebirths over a 3‐year period (1991–1993) revealed 472 cases (41.19 per 1,000 livebirths, 95% CI 37.48‐44.90) with 171 musculoskeletal defects (14.92 per 1,000 livebirths, 95% CI 12.69‐17.16), 105 cardiovascular defects (9.16 per 1,000, 95% CI 7.41‐10.91), 64 urogenital defects (5.58 per 1,000, 95% CI 4.22‐6.95), 30 gastrointestinal defects (2.62 per 1000, 95% CI 1.68‐3.55), 35 mixed system defects (3.06 per 1,000, 95% CI 2.04‐4.07), and 18 chromosomal abnormalities (1.57 per 1,000, 95% CI 0.85‐2.30). The prevalence of cleft lip/cleft lip and palate was 1.48 per 1,000. This higher prevalence could be due to the present practice of routine screening of every infant on the first day of life, together with a careful assessment for musculoskeletal defects, especially congenital dislocation of the hips.