A recent cohort study reported that about 15% of previously affected mothers had recurrent severe hypertensive disorders of pregnancy (HDP) in a subsequent gestation.

The highest recurrence risk was driven by the severity and timing of HDP in the index pregnancy: More than 1 in 5 patients with an index HDP between 28 and 34 weeks’ gestation or with index HDP before 28 weeks experienced recurrent HDP, according to the study published in Obstetrics & Gynecology.

As major contributors to maternal morbidity and mortality, HDPs have increased in incidence in the US over the past decade. HDPs are associated with unexpected and traumatic delivery experiences, especially when they occur at an early gestational age said researchers led by Emma Trawick, MD, of the Division of Maternal-Fetal Medicine at The University of North Carolina at Chapel Hill. These results can inform counseling to aid decision-making.

“Our research was inspired by the question we hear from patients every day: ‘What’s my risk of getting preeclampsia next time I get pregnant, and what can I do to prevent it?’” Trawick told Medscape Medical News. To better answer that question, the study asked how often severe preeclampsia recurs and does it recur as early and severely the second time around.

Retrospective Study

In a database inpatient registry, 560,295 mothers were identified as having two or more pregnancies from October 2015 to December 2020. HDP phenotypes were defined as preeclampsia with severe features, superimposed preeclampsia, HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome, or eclampsia. Of all included patients, 57,584 (10.3%) had HDP and 11,433 (2.0%) had severe HDP during the initial index pregnancy.

Of these patients, 1703 individuals (14.9%) experienced recurrent HDP in a subsequent pregnancy (relative risk [RR], 16.0; 95% CI, 15.2-17.0). Severe HDP before 28 weeks’ gestation had the highest subsequent risk: 22.9% (RR, 23.1; 95% CI, 19.1-27.9).

“Interestingly, when severe preeclampsia did recur, most [episodes] occurred at later gestational ages than in the initial pregnancy,” Trawick said.

As to recurrence timing, an initial severe HDP before 28 weeks’ gestation conferred the highest risk for another pre-28-week recurrence in a subsequent pregnancy: 4.7% ( RR, 184.9; 95% CI, 107.2-318.9).

Patients with a history of HELLP syndrome or eclampsia also had an elevated risk for subsequent severe HDP : 11.5% ( RR, 9.7; 95% CI, 8.3-11.3) and 11.0% (RR, 9.2; 95% CI, 7.2-11.8), respectively. “But the most severe forms of preeclampsia, HELLP, and eclampsia recurred infrequently, with HELLP occurring again in only 4.6% and eclampsia occurring again in 1.1%,” Trawick said.

As to other patient variables, those with a history of severe HDP more often identified as Black, were publicly insured, and had comorbidities including chronic hypertension, pulmonary hypertension, BMI of 40 or higher, pregestational diabetes, chronic kidney disease, and cardiomyopathy.

“Recurrence is not all or nothing,” Trawick said. “The risk depends on how early and how severe the hypertensive disorder was in the initial pregnancy. Hypertensive disorders affecting a second pregnancy may look different than those affecting the first.”

The study provides more precise population-based information for counseling patients about future risk, according to E. Nicole Teal, MD, MPH, a maternal-fetal medicine specialist at University of California, San Diego.

“Rather than treating all HDPs as having the same recurrence risk, we can better account for the timing and severity of the prior disease,” she said, noting that severe HDP before 34 weeks had about a 1 in 5 risk for severe HDP in the next pregnancy. “This can help inform counseling and how closely we monitor patients in subsequent pregnancies.”

Cardiovascular Disease Risk

Preeclampsia is also linked to increased risk for future cardiovascular disease, with risk in part related to recurrence, Trawick said. “More intensive cardiovascular prevention for these patients may improve long-term outcomes.”

Future research should focus on incorporating clinical risk factors, such as chronic hypertension, into the risk for recurrent preeclampsia. Clinicians and patients need better tools for preeclampsia prevention, she added, noting that while aspirin can reduce preeclampsia risk, it remains underprescribed. “Long-term, we also need to develop better strategies for monitoring and supporting patients after preeclampsia.”

Also commenting on the study but not involved in it, Jenna N. Skowronski, MD, director of cardio-obstetrics at The University of North Carolina at Chapel Hill, said, “[a]s a cardiologist who cares for women both during pregnancies complicated by HDP and later in life, these findings reinforce that HDP should not be viewed solely through an obstetric lens. A history of HDP is an opportunity to provide enhanced attention to cardiovascular risk factors and long-term prevention throughout a woman’s lifespan.”

Going forward, said Skowronski, we need to move from population-level estimates toward more individualized risk prediction. “We need validated tools that combine the timing and severity of prior disease with factors such as chronic hypertension and blood pressure control, kidney disease, diabetes, cardiovascular disease, body mass index, and inter-pregnancy interval.”

Teal added that an important next step is understanding why some patients experience recurrent severe disease while others do not. “We also need to determine how interventions such as low-dose aspirin and optimization of health between pregnancies can modify these risks. Ultimately, the goal is not only to predict recurrence more accurately, but to identify strategies that prevent it or reduce its severity.”

No specific funding was disclosed for this study. Co-author Jerome J. Federspiel, MD, PhD, disclosed funding from the National Institutes of Health and Koko Medical, as well as consulting for Noma, AI, Grifols, UCB, and Sanofi. Other authors reported having no conflicts of interest. Skowronski and Teal had no relevant conflicts of interest.