Risk factors for preterm birth: a case-control study in rural area of western China.

Preterm birth is the leading cause of perinatal morbidity and mortality in China, the study is to learn risk factors for preterm birth in rural area of western China. A 1:1 case-control study in which cases included the pregnant women of preterm birth and controls included the matched pregnant women of normal deliver was conducted in 5 counties in western China. Data about the general situation, pregnancy history, reproductive health infection (RTI) symptoms, pregnancy complications, et al were obtained by using questionnaire. The results showed that the risk factors related to preterm birth were including: family income, mother's age ≥ 35 years old, antennal visiting ≤ 4 times, low education level, preterm birth history, abnormal vaginal discharge, pregnancy complications. The logistic regression analysis showed that only 3 factors of preterm birth were left at the last step, which of antenatal visiting ≤ 4 times, PROM and placenta previa had significant difference. We show that family income, age, antennal visiting, low education level, preterm birth history, abnormal vaginal discharge, pregnancy complications are the risk factors of preterm birth.