Prepregnancy obesity status and risks on pregnancy outcomes in Shanghai: A prospective cohort study.

Obesity in women of reproductive age is not only associated with numerous adverse maternal and fetal effects prenatally but also exerts a negative influence on female fertility. The aim of this study was to investigate the situation of prepregnant obesity in Shanghai and explore the impact of prepregnant obesity on gestational weight gain as well as other pregnancy outcomes. A prospective hospital-based pregnant women cohort was established in Shanghai since January 2015. All pregnant women who were registered and expected to deliver in this hospital were included in the cohort. Nearly one fourth of pregnant women in Shanghai were overweight/obese and the prevalence of overweight/obesity was more common among women with advancing age (P < .001). Women prepregnancy overweight/obesity was associated with 3.5-fold higher risk of excessive gestational weight gain (odds ratio, OR 3.58; 95% confidence interval, CI, 2.82-4.55; P < .001). Women prepregnancy BMI was statistically related to pregnancy outcomes as macrosomia (OR 2.24; 95% CI, 1.55-3.23; P < .001), cesarean delivery (OR 2.04; 95% CI, 1.60-2.62; P < .001), maternal complications (OR 1.53; 95% CI, 1.18-1.98; P < .001). Prepregnancy obesity is associated with a much higher risk of excessive gestational weight gain and pregnancy outcomes in Shanghai. Further interventions targeting maternal obesity, especially prepregnancy obesity are required.