Leptin levels in mid-pregnancy and risk of preeclampsia

Our objective was to examine the association between mid-pregnancy leptin concentration and preeclampsia risk, adjusting for maternal risk factors.

We studied 1504 women with singleton pregnancies in the Project Viva cohort. The exposure was mid-pregnancy plasma leptin concentration (mean gestational age 28 weeks), categorized into tertiles. The primary outcome was preeclampsia during that pregnancy. The secondary outcome was self-reported preeclampsia during subsequent pregnancies. We used multivariable logistic regression to assess the association of leptin tertiles with preeclampsia, adjusting for pre-pregnancy BMI, first trimester gestational weight gain, history of hypertension, age, and parity.

There were two (0.4%) cases of preeclampsia among participants in the lowest leptin tertile, 20 (4.0%) in the middle tertile, and 29 (5.8%) in the highest tertile. Higher leptin levels were associated with higher odds of preeclampsia after adjustment for confounders. Compared to the lowest tertile, odds ratios were 7.5 (95% CI 1.7, 32.7) for the middle tertile and 7.0 (95% CI 1.5, 31.9) for the highest tertile. Higher leptin levels were also associated with higher odds of preeclampsia in subsequent pregnancies (6.1% vs 0.9% in the middle vs. lowest tertile, OR 6.4, 95% CI 0.7, 57.0), although the estimates were highly imprecise due to the small sample size.

Higher mid-pregnancy leptin concentrations were associated with increased risk of preeclampsia, independent of maternal age, pre-pregnancy BMI, first trimester gestational weight gain, history of hypertension, and parity. Additionally, our results suggest that elevated leptin during a prior pregnancy may increase preeclampsia risk in subsequent pregnancies.