Women between 34 0/7 through 36 6/7 gestational weeks with non-severe hypertensive disorders such as (1) gestational hypertension, (2) pre-eclampsia, (3) deteriorating pre-existing hypertension or superimposed pre-eclampsia were studied to determine if they should be delivered immediately or followed with close monitoring. The results of the study showed:
- There was no statistical risk reduction in adverse maternal outcomes in women who were delivered immediately (1.1%) compared to expectant management (3.1%)
- Maternal adverse events overall, such as thromboembolic disease, pulmonary edema and eclampsia, were relatively uncommon
- There was an increase in neonatal respiratory distress syndrome in the immediate delivery group (5.7%) compared to the expectant management group (1.7%) that was statistically significant (P=0.005) which required treatment with continuous positive airway pressure and/or surfactant
- Based on these findings, routine immediate delivery does not appear justified and expectant monitoring through 36 5/7 gestational weeks should be considered
In a multi-centered randomized controlled trial published in the Lancet (2015), investigators sought to determine the risks/benefits of immediate delivery compared to expectant monitoring in pregnancies between 34 and 37 weeks gestational age, following their initial study that demonstrated induction of labor compared to expectant monitoring after 37 0/7 weeks gestational age did reduce maternal harms but did not affect neonatal outcomes nor increase cesarean section rates (Lancet, 2009).
- Hypertensive disorders in pregnancy are common and can occur in up to 10% of all pregnancies
- In the case of non-severe hypertensive disorders, there does not appear to be sufficient benefit to delivery before 37 weeks gestation while there is risk of respiratory distress syndrome to the newborn