Neural tube defects: a different pattern in northern Thai population.

The objective of this descriptive study was to describe the demographic and sonographic patterns of fetal neural tube defects (NTDs) in Thai pregnant women. The study was conducted at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai University. The subjects included all pregnancies with diagnosis of fetal neural tube defects. Basic clinical data of the subjects was prospectively collected at the time of diagnosis for NTDs and followed-up until delivery. Antenatal diagnosis was based on sonographic criteria. The results showed that the incidence of NTDs was 0.66/1,000 births, however, spina bifida was very rare, found in only 0.06/1,000 births, similar to encephalocele. All anencephalic fetuses had no concurrent spina bifida, and only a few cases had other associated anomalies. Ultrasound was able to diagnose NTDs with very high accuracy. All cases of antenatal diagnosis were electively terminated. In conclusion, NTDs in the Thai population were rather rare when compared to that of the Europeans and spina bifida was extremely rare. The accuracy of antenatal diagnosis of NTDs with ultrasound was highly reliable.