Rebozo and maternal postures to prevent persistent occiput posterior position of the fetal head: protocol for a...

Occiput posterior position is the most common fetal malposition, complicating up to 35% of initial labours, and its persistence can lead to increased risks of adverse maternal and perinatal outcomes. The role of maternal postures, such as lateral recumbent and hands-and-knees, in promoting the anterior rotation of the fetal head has been investigated in several randomised trials in the last two decades, with mostly negative results. However, both methodological and study design limitations may have contributed to such findings. Recently, the use of forward-leaning inversion and side-lying release procedures and of the Rebozo technique has been implemented into clinical practice as a non-invasive alternative to promote the anterior rotation of the fetal head. Yet, neither intervention has been rigorously assessed in a controlled study. Our aim is to conduct a randomised controlled trial to assess whether a combination of forward-leaning inversion and side-lying release procedures and the Rebozo technique in a pre-specified sequence during the first stage of labour of women with a posterior fetus would favour its anterior rotation.

The ReMaP-POPP (Rebozo and maternal procedures to prevent persistent occiput posterior position of the fetal head) trial will be an open-label single-centre randomised controlled trial with two parallel groups. Women will be eligible if they are ≥18 years old, in labour (3 to 8 cm) and with a singleton term fetus (≥37^0/7 weeks) in an occiput posterior position confirmed by transabdominal sonography. Eligible women will be randomised into two groups: (1) intervention, a sequence of forward-leaning inversion and side-lying release procedures and Rebozo technique (duration 90-105 min); and (2) control, standard of care (maternal postures, including upright, lateral recumbent and hands-and-knees). Blinding will be guaranteed only for the physician assessing the fetal head position by sonography. Randomisation will be performed using randomly permuted blocks of varying sizes (4, 6 and 8), stratified by parity, in a 1:1 ratio. The primary outcome will be the probability of occiput posterior position of the fetal head 3 hours and 30 min after randomisation, diagnosed by sonography. Secondary outcomes will include the probability of occiput posterior position at full cervical dilation and at birth, maternal and neonatal health-related outcomes, as well as maternal pain intensity and ability to cope with pain and birth satisfaction level. We will also assess safety outcomes regarding challenges in adequate fetal heart rate monitoring during the time interval between randomisation and primary outcome assessment. Sample size estimation considered the possibility to decrease the probability of occiput posterior position from 35.8% (control, based on prior retrospective data at our Institution) to 22% with the proposed intervention. With a power of 0.90 and a two-sided value of 0.05, the estimated sample size will be n=462 (n=231/arm). Considering a potential attrition rate of 20%, n=578 women will be needed. Enrolment will require approximately 16 months. Primary and secondary outcomes will be analysed on an intention-to-treat basis. The effects of the intervention will be estimated by relative risks and their 95% CI.

The study has been approved by the Lombardy Ethics Committee n.3 (n. 5499, 20 December 2024). Written informed consent will be obtained from all participants. Women will be free to decline participation or to withdraw at any time. Findings will be presented at scientific meetings and published in peer-reviewed scientific journals in the field of midwifery and obstetrics. Also, they will be disseminated to the public through outreach activities involving families and healthcare specialists.

The study has been registered in the Clinical Trials database (NCT06887634).