Prevalence of Macrosomia and Its Risk Factors in China: A Multicentre Survey Based on Birth Data Involving 101 723 Singleton Term Infants

Background Macrosomia, defined as a birthweight at least 4000g, is a public health problem because of its adverse influences on maternal and neonatal outcomes. Studies show that there is an increasing prevalence of macrosomia births in developing countries. However, information on the epidemiology of macrosomia is limited in China. This study aimed to determine the prevalence and geographic variability of macrosomia in China and risk factors that can be targeted for intervention. Methods A hospital-based, cross-sectional survey was conducted in 14 provinces in China, covering a wide range of geographic areas. The medical records of 101723 singleton term infants born in 39 hospitals during 2011 were reviewed. Multiple logistic regression analysis was used to examine the associations between demographic characteristics and the risk of macrosomia. Results The total prevalence of macrosomia was 7.3%. The prevalence varied between provinces, ranging from 4.1% to 13.4%. The prevalence of macrosomia in northern China (8.5%) was significantly higher than that in southern China (5.6%). Logistic regression analyses showed that risk of macrosomia was positively associated with maternal age, pre-pregnant body mass index (BMI), gravidity, parity, maternal height, gestational weight gain (GWG), gestational diabetes mellitus (GDM), and male fetal sex. Maternal BMI, gestational week, and GWG were the three risk factors most strongly associated with macrosomia. Conclusions The prevalence of macrosomia varied dramatically between different areas of China. High pre-pregnancy BMI and GWG represent main modifiable risk factors for macrosomia and need more attention from health care providers.