Predictors for intrapartum cesarean delivery after labor induction for suspected fetal growth restriction at term

In term pregnancies with suspected fetal growth restriction (FGR) undergoing induction of labor (IOL), predictors for intrapartum cesarean delivery (CD) remain unclear. We aimed to determine predictors for intrapartum CD in this population.

This study included a retrospective cohort of singleton pregnancies undergoing IOL at ≥37 weeks for suspected FGR, defined as estimated fetal weight (EFW) or abdominal circumference (AC) <10th percentile, at a tertiary medical center (2011-2019). Maternal characteristics, sonographic measurements, and Doppler parameters were compared between vaginal delivery and intrapartum CD. Multivariable logistic regression and CHAID (Chi-square Automatic Interaction Detector) decision tree analysis were performed.

Of 428 inductions, 71 (16.6%) resulted in intrapartum CD, predominantly for non-reassuring fetal heart rate (88.7%). Mean maternal age was 31.3 ± 5.2 years, and 286 patients (66.8%) were nulliparous. Mean EFW was 2364.3 ± 252.7 g, corresponding to the 2.1st percentile. Overall, 273 fetuses (63.8%) were in the <3rd percentile. No differences in fetal biometry or Doppler flows were detected between groups, and neither parameter predicted intrapartum CD. The only independent predictors of intrapartum CD were nulliparity (adjusted odds ratio [aOR] 4.84, 95% confidence interval [CI] 2.26-10.37, P < 0.001) and maternal age (aOR 1.10 per year, 95% CI 1.04 to 1.16, P = 0.002). Decision tree analysis showed a low CD rate in parous patients (6.3%) versus 44.2% in nulliparous patients aged ≥35 years (P < 0.001).

When considering induction of labor for suspected FGR at term, maternal age and parity, rather than fetal size or Doppler status, should guide counseling regarding cesarean risk.