| Objective:1. To identify the risk factors of premature delivery. 2. To establish a scoring system for predicting premature delivery, in order to predict premature delivery or to screening high-risk group of pregnant women.Methods:part 1: A retrospective study was designed and a total of 723 pregnant women with premature delivery were included in our study, these women were divided into group A and B. The former including 541 cases was spontaneous premature delivery, while the later including 182 cases was iatrogenic premature delivery. Another 541 cases who delivered at term served as a control group ( group C). Part 2: 1 To study the relationship between bacterial vaginosis (BV) and premature delivery, a prospective study was conducted in 400 pregnant women, the BV was checked during the second trimester and their pregnant outcome was followed. 2 Another prospective study was designed for researching the relationship between cervical length and premature delivery, 332 pregnant women were included in this study, using tranperineum ultrasonograph measured the cervical length at 20~34 weeks gestational age , and their pregnant outcome were followed. Part 3: A scoring system of risk factor was established in order to predict premature delivery. Result:Parti:1 Among the 541 cases of spontaneous premature deliveries, 38.4% were premature rupture of membranes (PROM), 30.1% were idiopathic premature delivered and 9.4% were breech presentations; among iatrogenic premature deliveries, 30.75% were hypertensive disorder complicating pregnancy, 25.8% were placenta praevia or placenta abruption, 22.8% were induced labor because of fetal distress.2 PROM, previous historical premature delivery, severe anaemia, twin or multiple pregnancy, cervical incompetence, maternal lymphocyte member elevated abnormally were risk factors for spontaneous premature delivery, systemic antenatal care and blood group " O " were protective factors.3 Mortality rate and incidence of RDS of premature infant were inverse correlated with gestational age. Both of them were higher in gestational age <33 weeks than that ≥ 33 weeks, statistically there was a significant difference between two groups (P<0.05)4 There was a significant difference in the incidence of asphyxia of premature infant between gestational age< 34 weeks and gestational age≥ 34 weeks (P=0.044).5 Incidence of asphyxia and mortality rate in premature infant was significantly different between infant with birth weight <2Kg group and weight ≥ 2Kg group.6 RDS, pulmonary hemorrhage and septicemia were mainly causes of death for premature infant.7 Antepartum use of dexamethasone (DXM) decreased the incidence of RDS and mortality rate of premature infant before 33 weeks gestational age, there was a significantly different between treatment group and un-treatment group in the incidence of RDS and mortality rate, but no significant difference in DXM effect between two groups after 33 weeks gestational age.Part 2:1 BV affected 20% of pregnancies, there was no significant difference in the incidence of premature delivery between BV positive group and negative group (p= 1 >0.05). BV was not risk a factor for premature delivery.2 The incidence of premature delivery increased when cervical length was less than 3.5 cm (checked during 20~34 weeks gestational age)(p=0.01).Part 3:In our scoring system, when predictive value was 1, then the sensitivity was 92.86%, specificity was 83.52%, and missed diagnosis rate was 7.14%. when predictive value was 3, then the sensitivity was 52.38%, specificity was 96.70%, and misdiagnosis rate was 3.3%. Conclusion:1 PROM, previous historical premature delivery, severe anemia, twin or multiple pregnancy, cervical incompetence, maternal lymphocyte member elevates abnormally are risk factors for premature delivery, systemic antenatal care and blood group "O" were are protective factors.2 Less than 33 weeks gestational age, incidence of RDS and mortality rate of premature infant are higher than that of infant older than 33 weeks; less then 34 weeks gestational age, incidence of asphyxia in premature infant is higher than that of older than 34 weeks.3 Incidence of asphyxia and mortality rate of premature infant are higher in birth weight less than 2 Kg group than that of more than 2 Kg.4 There is non-significant difference in incidence of premature delivery between BV positive group and negative group, BV is not a risk factor for premature delivery.5 The incidence of premature delivery increases when pregnant women's cervical length is less than 3.5 cm (checked during 20-34 weeks gestational age).6 The scoring system for high-risk factor can be used for screening the high-risk group of premature delivery and for decided the interfere objects.
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