International study of sex ratio and twinning of neural tube defects.

摘要: The goal of this study, based on information collected from eight congenital malformation registry programs around the world, was to analyze sex and twinning affected infants fetuses, according type neural tube defect (NTD) other variables. its location, whether it occurred in isolated form or associated with malformations, population which data were retrieved, vital status infant, gestational age fetus/infant considered. material included 3,416 168 selectively aborted fetuses anencephaly, 4,830 76 spina bifida, 1,022 19 encephalocele. Less than 20% anencephaly bifida more one-third encephalocele had malformations. A female excess found among all NTD but a male delivered spontaneously before week 20, indicating selective late fetal deaths. Sex ratio varied by NTD, at birth, presence year an increasing for during 1960s 1970s. Twinning positively extent association program, while distribution pair twin appeared be similar that births. Twins concordant mainly when as part syndrome, only like-sexed pairs. 5 6 pairs like-sexed.(ABSTRACT TRUNCATED AT 250 WORDS)