Robillard PY, et al. - Researchers examined how BMI influences EOP (early onset preeclampsia) vs LOP (late onset), especially focusing on diabetes and maternal booking/prepregnancy BMI as possible independent variables via conducting 18 year-observational cohort study (2001–2018). All consecutive births delivered at the Centre Hospitalier Universitaire Hospitalier Sud Reunion’s maternity were included (ap. 4,300 birth per year, only level 3 maternity in the south of Reunion Island, sole allowed to follow and deliver all preeclampsia cases of the area). The strongest risk factors for EOP were chronic hypertension and, history of preeclampsia in multigravidas. However, LOP was observed in correlation with primiparity, age over 35 years and BMI ≥ 35 kg/m². They identified maternal age and prepregnancy BMI as independent risk factors for both EOP and LOP in multivariate analysis with EOP or LOP as outcome variables compared with controls (normotensive). However, rising maternal ages and incidence of preeclampsia were strictly parallel for EOP and LOP when analyzing by increment of 5 (years of age, kg/m² for BMI), while there was an association of the increment of BMI with only LOP. Diabetes was not identified as an independent risk factor for EOP or LOP when controlling for maternal ages and booking/prepregnancy BMI. In light of this work, explanation could be provided for the discrepancy that is observed nowadays where high-income countries report 90% of their preeclampsia being LOP, while it is only 60%–70% in medium-low income countries.