TOPLINE:

Complications during the first pregnancy such as gestational diabetes and hypertension, the risk for preterm delivery, and interpregnancy weight changes were associated with an increased risk for first-time preeclampsia during the second pregnancy.

METHODOLOGY:

• Researchers conducted a population-based cohort study using data from the Swedish Medical Birth Register to identify potential risk factors associated with first-time preeclampsia during the second pregnancy.
• They included 808,107 women with consecutive first and second singleton deliveries between 1992 and 2019 who did not have preeclampsia during their first pregnancy.
• The primary outcome was first-time preeclampsia during the second pregnancy.

TAKEAWAY:

• Overall, 9295 (1.1%) women developed first-time preeclampsia during the second pregnancy, of whom 1287 (20%) had preterm preeclampsia, defined as preeclampsia combined with delivery < 37 gestational weeks.
• Complications during the first pregnancy, such as gestational diabetes (adjusted relative risk [aRR], 1.54; 95% CI, 1.29-1.82), delivery of a small-for-gestational-age infant (aRR, 1.69; 95% CI, 1.54-1.85), gestational hypertension (aRR, 4.61; 95% CI, 4.20-5.05), and preterm delivery (aRR, 1.99; 95% CI, 1.87-2.12), were associated with increased risks for first-time preeclampsia during the second pregnancy.
• New-onset diabetes and essential hypertension between pregnancies were associated with a twofold (aRR, 2.08; 95% CI, 1.71-2.54) and a fivefold (aRR, 5.14; 95% CI, 4.76-5.54) higher risk for first-time preeclampsia during the second pregnancy, respectively. Longer interpregnancy intervals were also linked to a higher risk (aRR, 1.11; 95% CI, 1.11-1.12).
• Gaining 2-4 BMI units between pregnancies was associated with a higher risk for first‐time preeclampsia during the second pregnancy than maintaining stable weight (aRR, 1.57; 95% CI, 1.47-1.67), whereas losing more than 2 BMI units was associated with a lower risk (aRR, 0.63; 95% CI, 0.55-0.72).

IN PRACTICE:

"[This] study shows that risk factors for developing first-time preeclampsia in second pregnancy mirror those known for preeclampsia in first pregnancy, but also include first pregnancy complications (gestational diabetes, gestational hypertension, spontaneous and medically indicated preterm delivery and delivery of SGA [small-for-gestational-age]-infant) and factors relating to interpregnancy changes in health status (weight change, new-onset diagnosis of chronic hypertension or diabetes mellitus)," the authors wrote.

SOURCE:

This study was led by Hanna Carr, Clinical Epidemiology Division, Department of Medicine, Karolinska Institutet, Stockholm, Sweden. It was published online on September 01, 2025, in BJOG: An International Journal of Obstetrics and Gynaecology.

LIMITATIONS:

Despite adjusting for several measured confounders, the possibility of residual confounding cannot be ruled out. Although data collection regarding maternal weight during early pregnancy has increased over time, data were missing for 5.6% of deliveries in the 2010s.

DISCLOSURES:

This study received funding through grants from the Swedish state: ALF-agreement and Karolinska Institutet Clinical Scientist Training Programme. One author reported being a member of the steering committee for specific studies, and another reported receiving financial support and having research collaborations with various agencies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.