Transperineal Ultrasound Parameters in Predicting Mode of Delivery in Women with Prolonged Second Stage of Labour: Prospective Observational Study

Prolonged second stage of labour increases maternal and foetal morbidity. Digital vaginal examination for assessing foetal descent is subjective and operator-dependent. Transperineal ultrasound (TPUS) parameters, angle of progression (AOP) and head–perineum distance (HPD), offer objective assessment.

To evaluate TPUS parameters (AOP and HPD) as predictors of mode of delivery in women with prolonged second stage of labour and study their maternal and neonatal outcomes.

A prospective observational study was conducted at Maharaja Yashwant Rao Hospital, Indore. Two hundred pregnant women with prolonged second stage of labour (≥ 2 h in nulliparous women without epidural; ≥ 1 h in multiparous women) and cephalic presentation in occiput anterior position were enrolled. After clinical confirmation of full cervical dilation and foetal head at or below ischial spine, standardized TPUS was performed by a blinded radiologist. AOP and HPD values were recorded and correlated with mode of delivery (spontaneous vaginal delivery, operative vaginal delivery, or caesarean section). Maternal and neonatal outcomes were documented. Statistical analysis used independent t tests for continuous variables, Chi-square tests for categorical variables, and logistic regression to identify predictors of delivery mode.

Among 200 participants, mean AOP was 117.6 ± 11.3° (range 92–140°) and mean HPD was 4.2 ± 0.6 cm. An AOP ≥ 116° predicted vaginal delivery with sensitivity 80.6% and specificity 83.2% (AUC 0.89). HPD ≤ 3.5 cm also predicted vaginal delivery (AUC 0.86). The combined AOP + HPD model had an AUC of 0.92.

TPUS measurements of AOP and HPD are reliable, non-invasive adjuncts in predicting vaginal delivery and reducing unnecessary caesarean sections in prolonged second stage of labour.