Maternal and fetal characteristics for predicting risk of Cesarean section following induction of labor: pooled analysis of PROBAAT trials

• Published in: Ultrasound in obstetrics & gynecology 2022-01, Vol.59 (1), p.83-92
• Main Authors: Quach, D., Eikelder, M., Jozwiak, M., Davies‐Tuck, M., Bloemenkamp, K. W. M., Mol, B. W., Li, W.
• Format: Article
• Language: English
• Subjects: Adult; Birth Weight; Bishop score; Body mass; Body Mass Index; Body size; cervical ripening; Cervix; Cervix Uteri - diagnostic imaging; Cesarean delivery; Cesarean section; Cesarean Section - statistics & numerical data; Childbirth & labor; Failure analysis; Female; Fetus - diagnostic imaging; Fetuses; Gynecology; Humans; Indication; Induced labor; induction of labor; Labor; Labor, Induced - statistics & numerical data; Labor, Obstetric; Logistic Models; Maternal Age; Minority & ethnic groups; Obstetric Labor Complications - diagnosis; Obstetric Labor Complications - surgery; Obstetrics; Odds Ratio; Optimization; Parity; Predictive Value of Tests; Pregnancy; Prenatal Diagnosis - methods; Prenatal Diagnosis - statistics & numerical data; Randomized Controlled Trials as Topic; Regression analysis; Risk; Risk Factors; Secondary analysis; Spline functions; Ultrasonic imaging; vaginal delivery; Weight; White people
• ISSN: 0960-7692; 1469-0705
• DOI: 10.1002/uog.24764

ABSTRACT Objective Induction of labor (IOL) is one of the most widely used obstetric interventions. However, one‐fifth of IOLs result in Cesarean section (CS). We aimed to assess maternal and fetal characteristics that influence the likelihood of CS following IOL, according to the indication for CS. Methods This was a secondary analysis of pooled data from four randomized controlled trials, including women undergoing IOL at term who had a singleton pregnancy and an unfavorable cervix, intact membranes and the fetus in cephalic presentation. The main outcomes of this analysis were CS for failure to progress (FTP) and CS for suspected fetal compromise (SFC). Restricted cubic splines were used to determine whether continuous maternal and fetal characteristics had a non‐linear relationship with outcome. Optimal cut‐offs for those characteristics with a non‐linear pattern were determined based on the maximum area under the receiver‐operating‐characteristics curve. Adjusted odds ratios (aOR) were computed, using multivariable logistic regression analysis, for the associations between optimally categorized characteristics and outcome. Results Of a total of 2990 women undergoing IOL, 313 (10.5%) had CS for FTP and 227 (7.6%) had CS for SFC. The risk of CS for FTP was increased in women aged 31–35 years compared with younger women (aOR, 1.51 (95% CI, 1.15–1.99)), in nulliparous compared with parous women (aOR, 8.07 (95% CI, 5.34–12.18)) and in Sub‐Saharan African compared with Caucasian women (aOR, 2.09 (95% CI, 1.33–3.28)). Higher body mass index (BMI) increased incrementally the risk of CS for FTP (aOR, 1.06 (95% CI, 1.04–1.08)). High birth‐weight percentile was also associated with an increased risk of CS due to FTP (aOR, 2.66 (95% CI, 1.74–4.07) for birth weight between the 80.0th and 89.9th percentiles and aOR, 4.08 (95% CI, 2.75–6.05) for birth weight ≥ 90th percentile, as compared with birth weight between the 20.0th and 49.9th percentiles). For CS due to SFC, higher maternal age (aOR, 1.09 (95% CI, 1.05–1.12)) and BMI (aOR, 1.05 (95% CI, 1.03–1.08)) were associated with an incremental increase in risk. The risk of CS for SFC was increased in nulliparous compared with parous women (aOR, 5.91 (95% CI, 3.76–9.28)) and in South Asian compared with Caucasian women (aOR, 2.50 (95% CI, 1.23–5.10)). Birth weight