To investigate the risk factors in premature delivery and provid evidence for screening population in high risk of premature delivery.

A retrospective study of 724 pregnant women with premature delivery was carried out in the Third Affiliated Hospital of Guangzhou Medical University from June 2008 to December 2009, including 427 patients with spontaneous preterm birth and 297 patients with iatrogenic preterm birth. Five hundred patients were randomly selected by delivered at term as the control ground. Risk factors of premature delivery were analyzed with χ² test and logistic regression analysis.

(1) Incidence rate of premature delivery was 11.85%, including 59% spontaneous premature delivery and 41% iatrogenic premature delivery. (2) The risk factors of spontaneous premature delivery were premature rupture of membranes (71.19%, 304/427), multiple pregnancy (21.55%, 92/427), breech presentation (22.95%, 98/427), uterine malformation (3.04%, 13/427)and incompetence of cervical (0.70%, 3/427). (3) The risk factors of iatrogenic premature delivery were preeclampsia (41.08%, 122/297), pregnancy with medical and surgical diseases (29.63%, 88/297), multiple pregnancy (27.61%, 82/297), placenta factors (26.60%, 79/297), and gestational diabetes mellitus(23.57%, 70/297). (4) The risk factors of premature delivery were multiparity(OR=4.428), premature rupture of membranes(OR=5.149), preeclampsia(OR=2.637), multiple pregnancy(OR=13.958), placenta praevia(OR=14.586), pregnancy with medical and surgical diseases(OR=2.677), gestational diabetes mellitus(OR=3.719), fetal growth restriction(OR=14.378), breech presentation(OR=3.663)and IVF-ET(OR=5.658).

It is necessary to prevent the risk factors of premature delivery and avoid or delay the occurrence of premature delivery in order to improve the maternal and neonatal outcomes.