Idiopathic polyhydramnios and fetal gender

To determine the relationship between idiopathic polyhydramnios and fetal gender in the absence of fetal or maternal abnormalities.

This was a retrospective population-based register study. 295 women with singleton pregnancies complicated by idiopathic polyhydramnios (amniotic fluid index (AFI) higher than 24 cm) who were delivered at our institution from January 2002 till December 2012 were included. Only pregnancies with an uncomplicated outcome were accepted in this study. The incidence of the male to female fetuses was compared with the one in the general population.

Among pregnancies complicated by idiopathic polyhydramnios, the following gender distribution was found: 72.9% male and 37.1% female. The distribution in the general population was 51.5% female and 48.5% male. The mean AFI was significantly increased in male fetuses (p < 0.001). The increased AFI did not correlate with gestation age, fetal head circumference or estimated fetal weight.

Idiopathic polyhydramnios is more frequent in male normal fetuses than in female ones.