Predictors of Cesarean Birth During Labor According to Maternal
BMI
: Insights From a Multicenter
D
oppler‐Based Analysis
José Morales‐Roselló, Asma Khalil, Silvia Buongiorno, Maia Brik, Manel Mendoza, Carolina Di Fabrizio, Elisa Scarinci, Silvia Salvi ABSTRACT
Background
Maternal overweight and obesity are associated with increased cesarean birth rates, although the mechanisms linking maternal body mass index (BMI) to labor outcomes remain incompletely understood. Few studies have differentiated cesarean indications or incorporated fetal Doppler assessment.
Objective
To identify BMI‐specific maternal and fetal predictors of intrapartum cesarean birth, differentiating cesarean indications and incorporating fetoplacental Doppler parameters.
Study Design
This retrospective multicenter observational study included 3290 singleton pregnancies ≥ 35 weeks' gestation from tertiary centers in Spain, Italy, and the United Kingdom. Maternal, fetal, and perinatal data were collected, including maternal BMI, labor characteristics, delivery outcomes, and fetal Doppler indices. Multivariable logistic regression assessed determinants of cesarean birth for intrapartum fetal compromise (CS‐IFC) and failure to progress (CS‐FP) according to maternal BMI categories.
Results
Increasing maternal BMI was associated with higher rates of CS‐IFC (5.6%–9.9%) and CS‐FP (7.8%–10.9%). In normal‐weight women, elevated umbilical artery pulsatility index (PI), reduced middle cerebral artery PI, and induction of labor independently predicted CS‐IFC, while parity and induction predicted CS‐FP. In overweight and obese women, maternal factors, primarily parity, were the main determinants, whereas Doppler indices were not independently predictive. The frequency of a 5‐min Apgar score < 7 showed no significant trend across BMI groups ( p = 0.272). Although arterial cord pH < 7.10 was most frequent in obese women, the trend across BMI categories was not statistically significant ( p = 0.132).
Conclusion
Maternal BMI was associated with increasing rates of intrapartum cesarean birth. In stratified analyses, fetoplacental Doppler parameters were independently associated with CS‐IFC in normal‐weight women but not in women with overweight or obesity. However, the overall interaction test was not statistically significant, and these findings do not establish that the associations of all predictors differ according to BMI. The interaction involving MCA PI MoM warrants further investigation. Further studies are needed to assess the clinical value of BMI‐specific predictive approaches.