Sex differences in the incidence of certain congenital malformations: a review of the literature and some new data.

Abstract

AbstractPercentages of males with selected congenital malformations reported in a large number of studies have been tabulated and analyzed. Males more often than females have been reported to have congenital hydrocephalus, cleft lip with or without cleft palate, esophageal defects, omphalocele, anorectal defects, polydactyly, syndactyly, reduction deformities, and plantar flexion foot defects. More females have been reported to have anencephaly, spina bifida, cleft palate, simple umbilical hernia, and dorsal flexion and inward rotational foot defects. Down's syndrome has been reported more frequently in males in studies that included older patients and more frequently in females in studies restricted to newborn populations. Sources of data also appear to be related to interstudy variations in sex ratios of anencephaly, cleft lip with or without cleft palate, and isolated cleft palate. It is suggested that unequal sex‐specific risks of death (prenatal in the case of anencephaly) account for the observed variations in the reported sex ratios of these malformations.