Objective: To explore whether women with overweight or underweight before pregnancy would be at higher risk of adverse birth outcomes.
Methods: A retrospective study was conducted on 41,975 mothers who received health examination in 1997, and delivered a singleton live baby in 1999 or a singleton stillbirth from 1999 to 2000. Odds ratio (OR) and 95% confidence interval (CI) for stillbirth, preterm birth, and low birth weight (LBW) according to pre-pregnancy body mass index (BMI, kg/m2) by 3 or 7 groups, were adjusted for maternal age at delivery, socio-economic status, diabetes and parity using logistic regression model.
Conclusion: Overweight, especially obese women were at higher risk on preterm birth including moderately preterm birth, and very LBW. Moderately thin women also had a increased risk on LBW including moderately LBW. It may be beneficial for women with overweight and moderate to severe thinness to have desirable birth outcomes by weight control such as physical activity and diet control.