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Published on: February 5, 2019
Birth Outcomes Associated With Assisted Vaginal Birth in an Occipito-Posterior Position: Secondary Analyses of a
Lauren Hayes1, Meena Ramphul2, Deirdre J Murphy3
1The Coombe Hospital & Trinity College, University of Dublin, Dublin, Ireland.
Objective:
To investigate the morbidity associated with assisted vaginal birth (AVB) and an occipito-posterior (OP) fetal head position.
Design:
Observational study based on secondary analyses of a randomised controlled trial and cohort study.
Setting:
Two university affiliated maternity hospitals in Ireland.
Population:
A combined cohort of 1081 nulliparous women at term who were assessed for AVB in the second stage of labour.
Methods:
Univariable and multivariable logistic regression analyses were performed.
Main Outcome Measures:
Postpartum haemorrhage (PPH), obstetric anal sphincter injury (OASI), fetal acidosis, neonatal trauma, failed or abandoned AVB leading to caesarean section (CS).
Results:
Of the 1081 AVBs, a total of 192 (17.8%) had an OP position at the outset, with 103 of these (53.6%) rotated to occipito-anterior (OA) prior to AVB and 89 (46.4%) remaining OP. AVB completed in a non-rotated OP position compared with OP rotated to OA was associated with an increased risk of PPH (34% [30/89] vs. 15% [15/103], adjusted Odds Ratio (adj OR) 3.57; 95% Confidence Interval (CI) 1.68 to 7.58), OASI (22% [14/65] vs. 2% [2/98], adj OR: 12.62; 95% CI: 2.65 to 60.12) and CS (27% [24/89] vs. 5% [5/103], adj OR: 8.99; 95% CI: 3.14 to 25.74). There were no significant differences in neonatal outcomes. The diagnosis of OP was incorrectly assigned as either OA or occipito-transverse (OT) in 35 of the 192 cases (18.2%).
Conclusions:
This study highlights the associated morbidity when attempting an AVB with a non-rotated OP position rather than rotating to OA.
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