The risk of cesarean section after trial of labor in low risk pregnancies according to maternal body characteristics = The risk of cesarean section after trial of labor in low risk pregnancies according to maternal body characteristics

국문 초록 (Abstract)

목적: To evaluate the risk of cesarean section during spontaneous labor and success rate of vaginal delivery in term nulliparous women according to maternal height, prepregnancy body mass index (BMI) and gestational weight gain (WG).
방법: A retrospective study was conducted with 269 nulliparous women who gave birth at term gestational period in Kangbuk Samsung Hospital from March 2015 to March 2016. Pregnancies with planned cesarean section (n=28) were excluded. Various anthropometric measures and obstetric outcomes were reviewed and analyzed.
결과: Forty-two (17.4%) women underwent emergency cesarean section and among them, 19 cases (45.2%) were due to failure to progress (FTP). Maternal height was significantly shorter among women who underwent cesarean section due to FTP than those who delivered vaginally (161 cm vs. 163cm, p=0.039). However, prepregnancy BMI and WG were not associated with success rate of vaginal delivery in patients who experienced trial of labor in our data. In subgroup analysis, patients who gained weight during gestation below the recommended values from Institute of Medicine (IOM) demonstrated increased rate of vacuum assisted delivery than women who gained weight adequately (8.8% vs. 1.1%, p=0.044). Especially in women who were categorized as underweight before pregnancy according to IOM, patients with WG below recommendation showed higher rate of failure for vaginal delivery than those with adequate WG although the difference did not reach statistical significance (17.6% vs. 0%, p>0.05).
결론: Our study shows maternal height was the only important factor associated with successful vaginal delivery. Various studies from Western countries reported prepregnancy obesity or over WG were strongly associated with failure of vaginal delivery, however those factors were not significant in our study population, which was composed of Asian low risk pregnancies. Moreover, underweight BMI and WG below the recommended values seemed to be associated with higher cesarean section rate. Future research with large Asian population should be conducted further.