The mediating role of platelet indices on pre-pregnancy body mass index and late-onset preeclampsia

Objective To investigate whether platelet indices mediate the association between pre-pregnancy body mass index (pBMI) and late-onset preeclampsia (LOPE).Methods This study retrospectively collected cohort data from 1,198 pregnant women between July 2021 and June 2023. The relationships among pBMI, platelet indices, and LOPE were assessed using logistic regression and Pearson correlation analyses. Mediation analysis was employed to evaluate the mediating effects of PC and PCT on the association between pBMI and LOPE.Results Compared to the control group, pregnant women with a pBMI ≥ 25 kg/m2 had a 3.342-fold increased risk of subsequently developing LOPE. A significant positive correlation was observed between pre-pregnancy BMI and both PC and PCT at 16–19 weeks of gestation (p < 0.001), and elevated levels of PC and PCT were significantly associated with an increased risk of LOPE (p < 0.05). Mediation analysis demonstrated that PC and PCT partially mediated the association between pBMI and LOPE, accounting for 8.61% and 11.99% of the total effect, respectively.Conclusion A higher pre-pregnancy BMI is associated with elevated platelet indices in early pregnancy, and these elevated indices may partially mediate the association between pre-pregnancy overweight/obesity and LOPE.