Delayed Pregnancies After Preeclampsia Worsen Outcomes

DENVER — An interval of less than 1 year or at least 5 years between pregnancies was linked to an increased risk for adverse pregnancy outcomes in patients who had a history of preeclampsia, according to a research poster presented at the annual meeting of the Society for Maternal-Fetal Medicine (SMFM) 2025 Annual Pregnancy Meeting.

Odds of preterm delivery or cesarean delivery were 1.7 times greater for patients whose second consecutive pregnancy was at least 5 years after the first than for those with 12-23 months between consecutive deliveries, Ava Mandelbaum, BA, of Oregon Health & Science University, and her colleagues reported. Odds of gestational hypertension and maternal morbidity were also higher in this group.

Odds of gestational hypertension and preterm delivery were also modestly but significantly elevated in patients whose second pregnancy occurred less than 12 months after a first pregnancy with preeclampsia compared with an interval of 12-23 months.

“The most significant findings were increased risk for preterm delivery, severe maternal morbidity, and cesarean delivery in the group with pregnancy interval over 5 years,” Eran Bornstein, MD, vice chair of Obstetrics at Northwell Lenox Hill Hospital in New York City and a maternal-fetal medicine specialist, told Medscape Medical News. “Although some findings were statistically significant also for short interval, these were of small clinical magnitude,” he said.

He said that the data may help providers in counseling women after a delivery complicated by preeclampsia.

“As we know, these patients have higher risk for recurrence as well as increased risk for future cardiac disease,” Bornstein said, so “care should be individualized to optimize their health and reduce risks as well as taking into account interpregnancy interval.” Steps to reduce those risks, for example, include quitting smoking, managing hypertension, and reducing excess weight, he added.

Bornstein cautioned, however, that it’s necessary to have more information about the details of the study to fully understand its implications and limitations.

“Given that this study is presented in poster form, much of the study methodology is not completely clear, and it is important to assure they had corrected for some confounding variables, such as maternal age, severity of preeclampsia, mode of delivery, and more,” Bornstein said. “It is important to learn whether the findings are due to the long interpregnancy interval or due to older age in that group, for example.”

The retrospective cohort study looked at consecutive singleton births from 2008 to 2020 in California patients who had preeclampsia with their first delivery. The researchers divided interpregnancy intervals into five categories: Birth less than 12 months after the first pregnancy, 12-23 months later, 24-35 months later, 36-59 months later, and at least 60 or more months later.

The primary outcomes included gestational hypertension, preeclampsia, preterm delivery, cesarean delivery, and severe maternal morbidity.

Among 36,435 patients, 20.6% had an interpregnancy interval of less than 12 months, 29.7% had an interval of 12-23 months, 18.6% had an interval of 24-35 months, 19% had an interval of 36-59 months, and 12.2% had an interval of 60 months or more.

Compared with patients with an interval of 12-23 months between pregnancies, those whose second delivery was within a year of the first were significantly more likely to have gestational hypertension (adjusted odds ratio [aOR], 1.12; 95% CI, 1.02-1.24) and preterm delivery (aOR, 1.16; 95% CI, 1.05-1.28) in their second pregnancy. There was no association, however, between an interpregnancy interval less than 12 months and risk for preeclampsia or severe maternal morbidity.

At the other end of the spectrum, a second consecutive pregnancy occurring at least 60 months after a first pregnancy complicated with preeclampsia was linked to increased odds of four adverse outcomes, though, again, not preeclampsia.

An interval of 60 or more months was linked to increased odds of gestational hypertension (aOR, 1.17; 95% CI, 1.04-1.31) and preterm delivery (aOR, 1.72; 95% CI, 1.54-1.91). The longer interval was also associated with higher odds of cesarean delivery (aOR, 1.73; 95% CI, 1.51-1.99) and severe maternal morbidity (aOR, 1.43; 95% CI, 1.10-1.86).

“Preeclampsia is a serious pregnancy complication associated with severe maternal and neonatal morbidity as well as risk of future cardiac disease in the mother,” Bornstein said. “Women with a prior pregnancy complicated by preeclampsia should seek care with a maternal fetal medicine specialist to assure appropriate care focused on optimizing their health prior to future pregnancy, as well as surveillance of their cardiac health.”

Bornstein and Mandelbaum had no disclosures, and no external funding was noted.

Tara Haelle is a science/health journalist based in Dallas.