1 Department of Pediatrics, Hamadan University of Medical Sciences, Hamadan, IR Iran.

2 Department of Community Medicine, Hamedan University of Medical Sciences, Hamedan, IR Iran.


Preterm birth significantly affects the neonates’ survival. It also increases the risk of neonatal complications, prolongs the hospitalization period, and imposes high costs on the public health system. This study is aimed to assess the risk factors of the preterm birth.
Materials and Methods
This case-control study was carried out at a maternal referral hospital in Hamadan. The participants consisted of 470 preterm infants born in less than 37 weeks of gestational age (case group), and 470 term infants with normal gestational age (control group). Several variables including the neonatal birth weight, gestational age, type of delivery, the maternal age, history of infertility, birth order and maternal disease were compared in both groups. The collected data was extracted from the medical file and recorded in a pre-designed checklist; they were then analyzed using SPSS software (version 16.0).
Mean gestational age (34.4±3.34 vs. 39.1±1.09 weeks, p=0.001), and mean neonatal weight (2475.43±683.28 vs. 3122.64±409.89 gr, p=0.001) were lower in the case group compared to the control group. Multivariate logistic regression analysis showed a statistically significant association between the preterm birth and older maternal age (OR: 1.07), history of infertility (OR: 0.5), mother exposure to smoking (OR: 2.4), intrauterine growth restriction (IUGR) (OR: 0.99), C-section delivery (OR: 0.39) and maternal diseases (OR: 0.96).
This study showed that older maternal age, history of infertility, mother’s exposure to smoking, IUGR, C-section delivery, and maternal disease were independent risk factors for preterm birth. The identification of these factors is essential in reducing the risk of preterm birth.