Prevalence of congenital limb defects: Data from birth defects registries in three provinces in Southern Thailand

This is the first population-based study in Thailand on the prevalence of congenital limb defects (CLD). Data were obtained from recently established birth defects registries in three southern Thailand provinces during 2009-2013. Entries in the birth defects registries included live births, stillbirths after 24 weeks gestational age, and terminations of pregnancy following a prenatal diagnosis of fetal anomaly. The total of 186 393 births recorded included 424 CLD cases, giving an average prevalence of 2.27 per 1000 births (95% CI, 2.05-2.49). The most common CLD was talipes equinovarus (44.1%), followed by polydactyly (13.9%) and syndactyly (9.4%). The prevalence significantly increased with maternal age from 1.81 in mothers aged <30 years to 2.75 in mothers 30 to <35 years, and to 2.94 in mothers >= 35 years (P=0.004). Overall 9.4% of the CLDs were syndromic CLD, again with significantly greater percentages in pregnant women aged >= 35 years than the non-syndromic CLD (32.5% vs 17.5% respectively, P=0.03). In conclusion, the overall prevalence of CLD in the 3 southern Thailand provinces examined was 2.27 per 1000 births, and syndromic CLD was significantly higher in pregnant women aged >= 35 years than younger pregnant women.