An epidemiological survey on low birth weight infants in China and analysis of outcomes of full-term low birth weight infants

Background: Low birth weight (LBW) is one of the leading causes of adverse perinatal outcomes and is closely related to neonatal disease and death. The incidence of LBW has been increasing. The aim of this study was to investigate the current incidence rate and factors affecting low birth weight infants and perinatal outcomes of full-term low birth weight infants in mainland China. Methods: This paper describes a retrospective analysis of children born in 39 hospitals of different types in 14 different provinces, municipalities, and autonomous regions in seven districts within China throughout 2011. The data were first collected in hardcopy format and then entered into computer network databases. Data covering a total of 112,441 cases were collected. Cases were excluded if data were incomplete and in the case of miscarriage before 24 weeks of gestation, multiple pregnancies, or induction of labor due to fetal malformation, intrauterine death, and other reasons, leaving a total of 101,163 cases. SPSS 18.0 and SAS 9.2 statistical packages were used to analyze the collected data. Results: According to this research, the incidence of LBW in mainland China was 6.1%, which is higher than the 5.87% reported in 2000, and it varied across different areas. The incidence of LBW was significantly higher in tertiary care hospitals than in secondary care hospitals. LBW was found to be associated with maternal age of less than 20 years, low level of maternal education, previous histories of adverse pregnancies, and with pregnancy comorbidities and complications, such as hypertensive disorders during pregnancy, anemia, oligohydramnios, premature rupture of membranes, and gestational diabetes. The rates of stillbirths, severe neonatal asphyxia, and deaths among full-term LBW infants were 2.42%, 0.83%, and 3.49%, respectively. The rates of stillbirths and neonatal deaths among full-term LBW infants born by caesarean section were 0.5% and 1.0%, respectively, which was lower than vaginal delivery. Conclusions: The incidence of LBW has increased in China. LBW is a leading cause of adverse pregnancy outcomes. Health care during pregnancy and management of high-risk factors for LBW may reduce the incidence of LWB and the death rate of LBW infants.