Pnm-15: The Effect of Maternal Body Mass Index on Preterm Birth in Women Referring to Health Centers of Ardebil in 2010: Prospective Study

Background: The aim of this study was to evaluate the relationship between prepregnancy maternal body mass Index (BMI) and preterm birth. Materials and Methods: This study included 231 healthy pregnant women, without any risk factors of preterm birth, were classified into categories that were based on their body mass index. Association between BMI, weight in 28-32 weeks of pregnancy, gestational age in birth and rout of delivery were examined. Rates of preterm birth were compared. Results: In each BMI category, the percent of women who delivered a preterm infant was underweight 3.8%, normal 46.2%, overweight 7.7%, and obese 42.3%. There was not significant relationship between body mass index and preterm (p>0.8). Obese women had larger infants but there wasn’t significant relationship (p>0.7), and had more frequent cesarean delivery (OR=3.21, 95%CI=1.74-5.92) p=0.006). Weight in 28-32 weeks during pregnancy is poorly correlated with prepregnancy BMI (p=0.4) and preterm birth. Conclusion: In this survey, there wasn’t significant correlation between body mass index (BMI) before pregnancy and preterm labor less than 37 completed weeks and we suggest more study for evaluation between preterm labor mechanism in obese and non obese women.