Gestational weight gain and rate of late-onset preeclampsia: a retrospective analysis on 57 000 singleton pregnancies in Reunion Island

OBJECTIVES: To investigate in singleton term pregnancies (≥37 weeks gestation) if applying optimal gestational weight gains (optGWG) on our population could have an effect on the incidence of late-onset preeclampsia (LOP). DESIGN: 18.5-year-observational cohort study (2001–2019). SETTINGS: Centre Hospitalier Universitaire Hospitalier Sud Reunion’s maternity (French overseas department, Indian Ocean), the only maternity providing services to take care of all preeclamptic cases in an area with approximately 360 000 inhabitants. MAIN OUTCOMES AND MEASURES: Simulation rates of LOP between women achieving optimal versus inappropriate GWG (insufficient and excessive) in the non-overweight, overweight and class I–III obesity categories. RESULTS: Among 66 373 singleton term pregnancies with a live birth, and 716 LOP (≥37 weeks, LOP37), the GWG could be determined in 87% of cases. In a logistic regression model validating the independent association of optGWG, maternal ages and body mass index (BMI), primiparity, smoking habit, chronic hypertension with term preeclampsia, optGWG reduced the risk of LOP37, aOR 0.74, p=0.004. Primiparity, higher maternal BMI, chronic hypertension and higher maternal age increased the risk of LOP37. The ‘protective’ effect of optGWG appeared stronger in patients with overweight and obesity in a linear manner: 0.57% versus 1.07% (OR 0.53, p=0.003), overweight; class I obese (30–34.9 kg/m²), 0.70% vs 1.56% (OR 0.44, p=0.01); severe obesity (≥35 kg/m²) 0.86% vs 2.55% (OR 0.33, p=0.06). All patients with overweight/obesity together, OR 0.42, p<0.0001. CONCLUSIONS: Overweight and obesity may not result in a higher risk of developing LOP at term when a optGWG is achieved. The results of this large retrospective population cohort study suggest that targeted and strictly monitored interventions on achieving an optGWG might represent an effective method to reduce the rate of LOP and would have the potential to halve its rate in women with overweight/obesity. These findings suggest a potentially achievable pathway to actively counterbalance the morbid effects of high BMIs, so we solicit adequately powered prospective trials.