Anencephaly in Singapore: a ten-year series from 1993-2002

Tan KBL, Tan SH, Tan KH, Yeo GSH
Correspondence: Dr Kenny BL Tan, ktbl@pacific.net.sg

ABSTRACT
Introduction Anencephaly is a neural tube defect that is incompatible with life. Previous studies have suggested that there is a racial predilection for this condition. However, local studies have not shown a statistical difference between the races. The aim of this study is to examine the incidence and the demographical trend of this condition over a ten-year period.
Methods Data of patients with anencephaly born from 1993 to 2002 were retrieved from the National Birth Defect Registry and analysed.
Results There were a total of 267 cases of anencephaly in the ten-year period from 1993 to 2002, giving an overall incidence of 0.58 per 1,000 livebirths, with a decreasing trend noted. The incidence was highest among the Malay population, compared with the Chinese population (p-value equals 0.03) and other races. Abortion rates have also increased over the years, causing a reduction in livebirth rates for this condition.
Conclusion The overall incidence and birth incidence of anencephaly has seen a decreasing trend over the last ten years, with the latter being contributed significantly by early termination. More studies should be done to ascertain if improved folate supplementation has contributed to the drop in overall incidence. The incidence in the Malay population is significantly higher than other races and this phenomenon should be further examined.

Keywords: anencephaly, birth defects, neural tube defects, termination of pregnancy
Singapore Med J 2007; 48(1): 12–15