The Urgent Need to Optimize Gestational Weight in Overweight/Obese Women to Lower Maternal- Fetal Morbidities: A Retrospective Analysis on 59,000 Singleton Term Pregnancies

Objective : We retrospectively did a simulation applying the optimal gestational weight gain (optGWG) equation (that we have proposed in 2018) on our population, and observed if its effect on maternal/fetal morbidities in singleton term pregnancies (≥37 weeks). Design: Retrospective observational study. sample All singleton births maternity. database. Methods Mathematical simulation on a 19-year historical cohort (2001-2019). Main outcome measures : Five Maternal/fetal morbidities. Results : Beginning with overweight women, and enlarging the effect with the rise of different obesities (class I to III) and considering maternal pre- pregnancy BMI (ppBMI), individualized counselling women on their GWG (optimal gestational weight gain, optGWG) lowers significantly maternal/ fetal morbidities: in a logistic regression model among overweight/obese women, with the outcome optGWG, several morbidities have a negative coefficient as independent factors: cesarean-section, birthweight ≥ 4000 g, term preeclampsia, lowering the effect of rising maternal ppBMI per increment of 5 kg/m² (coefficient -0.13), all p < 0.001. We propose as a prediction to be verified in future prospective studies that a follow-up and counselling since the first prenatal visit should also lower gestational diabetes mellitus rates. Conclusion : We may have significant health (and cost) benefits by lowering c-section rates, term preeclampsia, macrosomic babies and LGA babies in overweight/obese women and low-birthweights babies in lean women. We may have much to win from reducing weight gain during pregnancy in overweight/obese women. It is urgent to verify and establish in all continents the specific linear-curve of optGWG for each geographic/ethnic area.