Impacted fetal head: a retrospective cohort study of full dilatation caesarean section

This study aims to determine the incidence, risk factors - including maternal demographics and intrapartum characteristics - and maternal and neonatal outcomes of fully dilated caesarean sections (FDCS) with impacted fetal head (IFH) compared to those without. It also seeks to evaluate the management techniques used in FDCS cases complicated with IFH.

Retrospective cohort study of singleton, cephalic pregnancies undergoing FDCS over one year (October 2024 - October 2025). Cases with and without IFH were compared using student's t-test, Mann-Whitney U and chi-squared tests (SPSS version 29.0). Where IFH occurred, additional techniques were recorded and summarized as frequencies and proportions.

Of 1,134 category 1 and 2 emergency caesarean sections with documented cervical dilatation, 105 (9%) were performed at full dilatation. IFH was documented in 58% of FDCS. There was no observed difference in intrapartum characteristics (i.e. induction of labour, oxytocin use, trial of instrumental) between groups. Additional techniques were required in 42% of IFH cases, most commonly vaginal push up (52%). IFH was associated with longer incision-to-delivery time (27% (16/59) taking ≥ 3 min versus 0% (0/43) , p < 0.001), surgical time (31% (18/59) taking over one hour versus 9% (4/43) those without, p = 0.01) and lower Apgar scores at 1 min (8 [1-9] versus 9 [5-10], p = 0.003) ; other operative, postnatal and neonatal outcomes demonstrated no meaningful difference across groups.

IFH at FDCS was commonly documented (58%), and greater than previously reported, likely due to variation in definitions and increased recognition. Findings highlight the need for a refined, consensus definition of IFH and enhanced clinical training to manage this important obstetric emergency and optimise outcomes.