[Relationship between reproductive history and preterm births in the last pregnancy, in Shaanxi province].

Objective: To analyze the incidence of preterm delivery among single live neonates and the association between maternal reproductive history and preterm birth. Methods: A questionnaire survey was conducted on reproductive history among women at childbearing age who were selected through multi-stage stratified random sampling method in Shaanxi, during 2010-2013. Samples would include women at childbearing age and in pregnancy or having had definite pregnancy outcomes. Results: A total of 29 608 women at childbearing age with their infants, were studied. The overall incidence of premature delivery among the single live birth neonates under this study, was 2.7% during 2010-2013. Results from the logistic regression model showed that factors as: having had history with preterm delivery (OR=7.99, 95%CI: 5.59-11.43), age of the mothers, older than 35 (OR= 2.03, 95% CI: 1.59-2.59) and with history of birth defects (OR=1.54, 95% CI: 1.01-2.34) were at higher risks for premature delivery in neonates. Intervals on pregnancies between 3-4 years (compared with ≤2 years, OR=0.74, 95% CI: 0.58-0.93), between 5-6 years (compared with ≤2 years, OR=0.66, 95%CI: 0.52-0.82), or> 6 years (compared with ≤2 years, OR=0.48, 95%CI:0.37-0.61) together with numbers of parity as 1 (compared with primiparas, OR=0.80, 95%CI: 0.67-0.95), as ≥2 (compared with primiparas, OR=0.62, 95% CI: 0.39-0.97) etc. were protective factors to preterm delivery. Factors as: history of preterm delivery, mothers age (older than 35 years) and intervals of pregnancy, appeared influential to the age of gestation, under the ordinal polytomous logistic regression analysis. Conclusion: The incidence of preterm births among single live birth neonates in Shaanxi was lower than the average national level. Programs related to health care services prior to conception and during pregnancy, together with increasing the self-care consciousness of childbearing aged women etc, should all be strengthened in order to reduce the occurrence of preterm birth, in Shaanxi province.