OS015. What is the optimal time for delivery in women with gestationalhypertension?

There is conflicting evidence regarding the treatment of women with gestational hypertension (GHTN).

To assess the optimal timing of delivery for women with GHTN by quantifying the risks of adverse maternal and fetal outcomes associated with ongoing pregnancy and with induction of labor at each gestational week 36-41 completed weeks.

The Consortium on Safe Labor electronic database from 19 hospitals across the US with 228,668 deliveries 2002-2008 was used to extract data on gravidas with GHTN, diagnosis assigned at delivery admission, using standard definitions. We only considered the first pregnancy to avoid intra-person correlation. Pregnancies complicated by diabetes mellitus, cardiac, pulmonary, or renal disease were excluded. The week-specific rates of maternal and neonatal morbidity/mortality (M/M) were calculated following induction of labor. Maternal outcomes included serious morbidity (composite defined as any of: ICU admission, abruption, large blood loss (>0.5L SVD, >1.0L CS), postpartum HTN) and mortality. Neonatal outcomes included SGA (⩽10th %tile), serious morbidity (composite defined as any of: seizures, severe respiratory morbidity or 5-min Apgar score ⩽3) and mortality. Pointwise 95% CI were calculated around each of these gestational age-specific rates. Statistical analyses were performed using FREQ, GLM and LOGISTIC procedures in SAS 9.2.

Following induction of labor, the rate of maternal M/M reached a nadir of 89.6 per 1000 live births [95% CI 67.8,111.5], at 38-38 6/7 weeks gestation, while the rate of neonatal M/M fell to 10.5 per 1000 live births [95% CI 2.8,18.2], at 39-39 6/7 weeks. The rate of SGA ⩽10th ‰decreased sharply between 36 and 37 weeks from 109.7 [95% CI 69.9,149.5], to 52.0 [95% CI 31.3,72.7].

In women with GHTN, induction of labor prior to 38weeks results in greater maternal M/M, but for the neonate induction at 39weeks results in lowest M/M.