乌鸦传媒

Pregnant women with chronic hypertension who were delivered early or were allowed to deliver late had increased risks of a variety of adverse outcomes, including preeclampsia as well as neonatal problems, a small retrospective cohort study found.

Among those having "planned deliveries" at 36 weeks gestation, a composite of stillbirth, neonatal death, assisted ventilation, and neonatal seizures (the study's primary endpoint) was roughly four times as common than in women who continued their pregnancies ("expectant management"), at 10.0% versus 2.6% (P=0.04), reported , of the University of Alabama at Birmingham, and colleagues.

However, those women who received expectant management after 38 weeks gestation (full-term) had nonsignificant increases in the primary endpoint compared with women having planned deliveries during this period, they wrote in .

After 39 weeks, women with chronic hypertension who received expectant management showed a significant increase in severe preeclampsia versus women with planned deliveries, 10.3% versus 0% (P=0.001).

"The findings of this study do suggest that the nadir of morbidity for babies born to women with chronic hypertension occurs after 38 weeks and before 40 weeks," Harper told 乌鸦传媒 via email. "These results are consistent with [the American College of Obstetricians and Gynecologists'] [of these women] by 40 weeks."

Previous recommendations have spanned a broad range, the researchers noted, from 36 to 39 weeks gestation, with the underlying evidence inconsistent.

Study Details

The study included 683 women with chronic hypertension. Baseline renal disease was significantly higher among patients with planned delivery at <39 weeks gestation. Use of antihypertensive medication and average blood pressures prior to delivery were not significant when comparing both delivery groups.

Almost half of the cohort underwent planned delivery (44.3%) at 39 weeks gestation, while only a small portion of those from 36 to 38 weeks gestation did. But there was no significant difference in the primary outcome between women who received expectant management compared with those who underwent planned delivery at 37-39 weeks gestation.

Examining secondary outcomes, there were no statistically significant differences between expectant management and planned delivery until 38 weeks gestation. After 39 weeks gestation, planned delivery was linked to an increased risk of primary cesarean delivery (relative risk 1.9). While the incidence of a longer neonatal length of stay was higher with a planned delivery, the difference was not statistically significant.

Harper acknowledged separately that larger studies and more data are needed on the subject.

"Due to the relatively few stillbirths and perinatal deaths, we were unable to examine the risk factors in women with chronic hypertension for these events, such as number of blood pressure medications being used or other chronic medical conditions," she told 乌鸦传媒. "Future studies should focus on the timing of delivery -- preferably a large, randomized trial that can randomly assign women to a gestational age for delivery to examine outcomes between groups."

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