Inducing labor at 38 or 39 weeks of gestation may benefit women with isolated chronic hypertension by preventing severe hypertensive events without increasing the risk of cesarean delivery, according to a study published in Obstetrics & Gynecology. In addition, the study suggests that labor induction at 39 weeks of gestation may be linked with a reduced risk of neonatal respiratory morbidity compared with expectant management.
An international group of researchers performed a retrospective, population-based study of women with chronic hypertension who had a singleton birth at 38 weeks of gestation to determine whether there was an association between labor induction at 38 or 39 weeks of gestation in expectant mothers with chronic hypertension and any risk of superimposed preeclampsia or cesarean delivery.
Expectant mothers who underwent labor induction for chronic hypertension between 38 weeks and 38 weeks and 6 days (n=281 women) were compared with expectant mothers who were expectantly managed during the same week and did not deliver at 39 weeks (n=1606 women).
In another analysis, expectant mothers who underwent labor induction for chronic hypertension at 39 weeks to 39 weeks and 6 days (n=259 women) were compared with mothers who did not deliver until 40 weeks of gestation (n=801).
Chronic hypertension was reported in 1.1% of the 534,529 mothers who gave birth (n=6054 women); of these women, 2420 were eligible for the study.
Women who were managed expectantly at 38 and 39 weeks were at risk for superimposed preeclampsia (19.2% and 19.0%, respectively) and eclampsia (0.6% and 0.7%, respectively). Later in gestation, more than half of those women underwent induced labor (56.8% and 57.8%, respectively).
Cesarean delivery risks were lower in 38-week induction groups or similar in 39-week induction groups to women who were managed expectantly at the same weeks. For 38 and 39 weeks, the adjusted relative risks were 0.74 and 0.90, respectively.
“Our findings suggest that in women with isolated chronic hypertension, induction of labor at 38 or 39 weeks of gestation may prevent severe hypertensive complications without increasing the risk of cesarean delivery,” the authors concluded. “Although these findings should be interpreted with caution give the limitations described, we believe that for care providers and women with isolated chronic hypertension who are considering induction of labor before 40 weeks of gestation, the current study may provide support for such a practice,” they continued.
Ram M, Berger H, Geary M, et al; for the Diabetes, Obesity and Hypertension in Pregnancy Research Network (DOH-NET) and the Southern Ontario Obstetrical Network (SOON) Investigators. Timing of delivery in women with chronic hypertension. [published online August 6, 2018]. Obstetrics & Gynecology. doi: 10.1097/AOG.0000000000002800