Incidence and risk factors of low birth weight in Tongzhou district of Beijing: 2013 – 2017

  Objective  To explore the incidence and risk factors of low birth weight (LBW) among newborns in Tongzhou district of Beijing from 2013 to 2017 and to provide evidences for developing effective interventions to reduce LBW rate.

  Methods  The data on demographics, pregnancy history, and current pregnancy for all pregnant women with singleton births from 2013 to 2017 (n = 34 726) were collected from Hospital Information System of Tongzhou district and then analyzed retrospectively to explore the incidence and influence factors of low birth weight. Multivariate logistic regression analysis was used to analyze risk factors of LBW.

  Results  The incidence of LBW was 2.79% and increased significantly in the district during the 5-year period (χ²_trend = 3.99, P < 0.05). Of all the LBW neonates, 10.7% were very low birth weight and the proportion of moderate LBW increased significantly (χ²_trend = 4.85, P < 0.05). Multivariate regression analyses revealed following risk factors for LBW: maternal stature of less than 160 cm (odds ratio OR = 2.66, 95% confidence interval 95% CI: 1.71 – 4.12), maternal stature between 160 cm and 169 cm (OR = 1.63, 95% CI:1.07 – 2.49), maternal unemployment or underemployment (OR = 1.22, 95% CI: 1.01 – 1.46), being a primipara (OR = 1.44, 95% CI: 1.20 – 1.74), placenta previa (OR = 2.22, 95% CI: 1.32 – 3.72), hypertensive disorder complicating pregnancy (OR = 4.59, 95% CI: 3.64 – 5.78), preterm birth (OR = 69.69, 95% CI: 58.51 – 83.01), and with a female neonate (OR = 1.34, 95% CI: 1.13 – 1.59). Stratified multivariate analyses further confirmed that short maternal stature, placenta previa, placental abruption, premature rupture of membranes, and hypertensive disorder complicating pregnancy were risk factors of preterm LBW; while, short maternal stature, primipara, hypertensive disorder complicating pregnancy, and with a female neonate were risk factors of term LBW.

  Conclusion  The incidence of low birth weight increased obviously during 2013 to 2017 in Tongzhou district of Beijing. Early intervention on low birth weight should be conducted among the pregnant women at high risk to reduce the incidence of low birth weight.