Effects of pre-pregnancy body mass index and gestational weight gain on neonatal birth weight in women with gestational diabetes mellitus

Aim: To study the impact of pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) on neonatal birth weight in women with gestational diabetes mellitus (GDM). Methods: This was a prospective cohort study of 622 singleton pregnant women diagnosed with GDM recruited from 1 April 2014 and 30 December 2014 in a university teaching hospital in China. Binary logistic regression was used to analyze the factors influencing macrosomia. Results: Pre-pregnancy BMI categories were: underweight (10.6%), normal (65.6%), overweight (18.0%) and obese (5.8%). Mean GWG was 14.4 +/- 4.8 kg and birth weight 3353.1 +/- 467.3 g. The incidence of macrosomia was 7.8% and low birth weight 2.3%. Logistic regression analysis showed that pre-pregnancy BMI was not associated with macrosomia. However, excessive GWG was a risk factor for macrosomia (odds ratio (OR) 2.884, 95% confidence interval (CI) 1.385-6.004, p < 0.01). In addition, high maternal fasting plasma glucose (FPG) (OR 1.933, 95% CI 1.126-3.316) and serum triglyceride (TG) (OR 1.235, 95% CI 1.053-1.449) in the third trimester of pregnancy were risk factors for macrosomia. Conclusions: Patients with GDM can be advised that excessive GWG and uncontrolled hyperglycaemia influence their chances for macrosomia.