Is there a seasonal variation in the diagnosis of oligohydramnios?

Abstract

Maternal dehydration is known to reduce amniotic fluid volume. Because dehydration is more common in warm weather we hypothesized that oligohydramnios would be diagnosed more frequently in the warm summer months. We examined the presence or absence of a clinical diagnosis of oligohydramnios at the time of admission to labor and delivery in four completed NICHD MFMU Network protocols [Asthma Observational (ASTH), Antibiotic Treatment of BV/TV for Prevention of Preterm Birth (BV/TV), Low-Dose ASA to Prevent Preeclampsia in High-Risk Women (HRA) and Low-Dose ASA to Prevent Preeclampsia in Low-Risk Women (LRA)]. The four studies included 9095 women, with 2296 in ASTH, 2489 in BV, 1697 in HRA and 2613 in LRA. The diagnosis of oligohydramnios was made significantly more frequently in June/July/Aug (p<0.05∗∗ comparing June/July/Aug to remainder using Fisher's exact test). In these studies the diagnosis of oligohydramnios is made more frequently in the warm summer months. Although not proven by this association, maternal dehydration may contribute to this finding and maternal hydration may reduce the frequency of clinical oligohydramnios during warm weather.Tabled 1Frequency of Oligohydramnios by QuarterTOTALASTHBV/TVHRALRAMONTHD/J/F5.5%6.0%5.5%6.3%4.8%M/A/M5.9%6.1%5.7%6.9%5.2%J/J/A7.2%∗∗8.1%7.3%8.8%5.3%S/O/N6.1%5.2%6.9%8.0%5.0%TOTAL6.2%6.4%6.3%7.5%5.1% Open table in a new tab