Is there a seasonal variation in the diagnosis of oligohydramnios?

Objective. We hypothesized that oligohydramnios would be diagnosed more frequently in the warm summer months when dehydration might be more common. Methods. The clinical diagnosis of oligohydramnios was extracted from the databases of four completed National Institute of Child Health and Human Development Maternal Fetal Medicine Units Network protocols. These data were stratified by quarter of delivery and compared using Fisher's Exact Test. Results. The clinical diagnosis of oligohydramnios was made more frequently in deliveries occurring in the summer months of June, July and August as compared with the remainder of the calendar year (7.2% vs 5.9%, p = 0.0178). Conclusions. In these studies the diagnosis of oligohydramnios is made more frequently in those pregnancies delivered during the summer months. Although not proven by this association, maternal dehydration may contribute to this finding.