Lateral asymmetric decubitus position for the rotation of occipito-posterior positions: multicenter randomized controlled trial EVADELA.

Background: Fetal occiput posterior positions are associated with poorer maternal outcomes than occiput anterior positions. Although methods that include instrumental and manual rotation can be used at the end of labor to promote the rotation of the fetal head, various maternal postures may also be performed from the beginning of labor in occiput posterior position. Such postures might facilitate flexion of the fetal head and favor its rotation into an occiput anterior position.
Objective: The purpose of this study was to determine whether a lateral asymmetric decubitus posture facilitates the rotation of fetal occiput posterior into occiput anterior positions.
Study Design: Evaluation of Decubitus Lateral Asymmetric posture was a multicenter randomized controlled trial that included 322 women from May 2013 through December 2014. Study participants were women who labored with ruptured membranes and a term fetus that was confirmed by ultrasound imaging to be in cephalic posterior position. Women who were assigned to the intervention group were asked to lie in a lateral asymmetric decubitus posture on the side opposite that of the fetal spine during the first hour and encouraged to maintain this position for as long as possible during the first stage of labor. In the control group, women adopted a dorsal recumbent posture during the first hour after random assignment. The primary outcome was occiput anterior position at 1 hour after random assignment. Secondary outcomes were occiput anterior position at complete dilation, mode of delivery, speed of dilation during the active first stage, maternal pain, and women's satisfaction.
Results: One hundred sixty women were assigned to the intervention group, and 162 women were assigned to the control group. One hour after random assignment, the rates of occiput anterior position did not differ between the intervention and control groups (21.9% vs 21.6%, respectively; P=.887). Occiput anterior rates did not differ between groups at complete dilation (43.7% vs 43.2%, respectively; P=.565) or at birth (83.1% vs 86.4%, respectively; P=.436). Finally, the groups did not differ significantly for cesarean delivery rates (18.1% among women in lateral asymmetric decubitus and 14.2% among control subjects (P=0.608) or for speed of cervical dilation during the active first stage of labor (P=.684), pain assessment (P=.705), or women's satisfaction (P=.326). No maternal or neonatal adverse effect that was associated with either posture was observed.
Conclusion: Lateral asymmetric decubitus position on the side opposite that of the fetal spine did not facilitate rotation of fetal head. Nevertheless, other maternal positions may be effective in promoting fetal head rotation. Further research is needed; posturing during labor, nonetheless, should remain a woman's active choice.
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