Amir Almasi-Hashiani - Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, Academic Center for Education, Culture, and Research, Tehran, Iran
Mohammad Ali Mansournia - Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
Mahdi Sepidarkish - Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, Academic Center for Education, Culture, and Research, Tehran, Iran
Arezoo Esmailzadeh - Department of Obstetrics and Gynecology, Zahedan University of Medical Sciences, Zahedan, Iran

Background: Gestational weight gain (GWG) is an important issue for all pregnant women due to its effect on pregnancy outcomes. Regarding this, the aim of the present study was to assess the relationship of GWG with cesarean section, birth weight, and gestational age at birth in the women with a pre-pregnancy body mass index (BMI) of ≥ 25 kg/m2. Methods: This cross-sectional study was conducted on 2,147 obese or overweight pregnant females who had singleton births as a secondary analysis. The data were collected by filling out a checklist in 103 hospitals, which were equipped with department of obstetrics and gynecology, in Tehran province, Iran, in 2015. Data analysis was performed using binomial logistic regression model in Stata software version 14. Results: According to the results, the prevalence of cesarean section was 74.35%. Furthermore, the mean GWG was 11.7 kg. The odds of cesarean delivery in the women with low and high GWG were 0.62 times smaller and 1.20 times larger than that for normal GWG, respectively (95% CI: 0.42-0.92, P=0.019 and 95% CI:0.90-1.59, P=0.197, respectively). After adjusting for confounding variables, GWG had no significant association with birth weight and gestational age at birth in the overweight and obese women. Conclusion: The findings of this study revealed a significant relationship between GWG and cesarean section. Furthermore, the odds of cesarean section in the women with low GWG was less than that in the women with normal GWG. Regarding this, GWG should be considered as one of the determinants of cesarean delivery. Therefore, it is suggested to conduct further prospective cohort studies to clarify the impact of GWG on pregnancy complications.

Cesarean delivery, Gestational weight gain, Low birth weight, Preterm delivery