The range of neural tube defects in southern India.

During a prospective study of 3500 consecutive births from November 1985 to January 1987 at three hospitals, 40 babies were found to have neural tube defects, an extremely high incidence (11.4/1000 births). The defects comprised anencephaly (n = 18), meningomyelocele (n = 11), Arnold-Chiari deformity (n = 3), encephalocele (n = 3), iniencephaly (n = 2), and one each of occipital meningocele, spina bifida occulta, and anencephaly with rachischisis. There were significant differences in incidence between those with consanguineous and nonconsanguineous parents and those whose mothers had previously given birth to malformed infants or who had had miscarriages, and those who had not. Significantly more defects were found among stillborn and low birthweight babies, among girls, and among those whose mothers were aged between 20 and 30 years. Just over a third (14) were breech presentations, and hydramnios was present in 16 (40%).