Background and rationale
Posterior fetal presentations are encountered in the delivery room on a daily basis given that they make up 10–20% of fetal positions in the second stage of labor and 5–8% of fetal positions when the fetus is expelled [
1‐
3].
Posterior positions are associated with a decreased rate of spontaneous vaginal deliveries. Indeed, the rate of instrumental delivery is estimated at 25–82% for posterior positions [
1,
4‐
6]. Cesarean section rates are 44.4% for posterior positions, versus 4.2% for anterior positions [
4,
5].
Spontaneous vaginal delivery is associated with lower morbidity rates, especially when the fetus is in an anterior position: there is a decrease in the rate of postpartum hemorrhage (PPH), infection, and perineal tear [
4,
5]. Furthermore, vaginal delivery improves the patient’s satisfaction in the short and long term (higher satisfaction rates) [
7,
8], with a decrease in psychological morbidity (lower rates of postpartum post-traumatic stress [
9], baby blues, and postpartum major depression [
10]). Spontaneous vaginal delivery improves the mother-child relationship, as has been evidenced by higher maternal breastfeeding rates when compared to cesarean section [
11].
The management of labor should, therefore, focus on achieving spontaneous vaginal delivery in order to improve the mother’s wellbeing and health.
Manual rotation of a posterior position to an anterior position at full dilation is a common and accepted practice in obstetrics, especially as it seems that rotation using the Neville-Barnes forceps is no longer performed due to maternal and fetal complications, and is no longer taught [
12,
13]. No current data recommends performing a rotation with other instruments (vacuum, spatula, etc.) in the event of a posterior position.
Manual rotation appears to be a simple method; Magnin therefore recommends trying to perform a systematic manual rotation for the posterior position. The efficacy of this maneuver was studied by Le Ray et al. in 2013 with a success rate of 90.1% and a vaginal delivery rate of 76.8% when performing manual rotation [
14]. Although the results of this non-comparative study are encouraging, the external validity of manual rotation in this study is not assessable as an experienced team performed them.
Manual rotation seems to be associated with reduced rates of instrumental fetal delivery and maternal complications. In a retrospective study in 2006, Shaffer et al. demonstrated that cesarean section rate was lower among patients for whom a successful manual rotation was performed than among those who had a failed manual rotation with delivery in the occiput posterior (OP) position (2% vs 34%,
p < 0.001) [
15]. However, in Shaffer’s study, there is a lack of a control group without manual rotation, so it was, therefore, impossible to know whether this result was only due to manual rotation or to potential interfering factors. In 2010, Shaffer et al. compared manual rotation to expectant management in a retrospective study and found a significant decrease in the cesarean section rate (adjusted odds ratio (aOR) 0.12; 95% confidence interval (CI) 0.09–0.16 [
16]). Nevertheless, there was a significant bias in this study because the “expectant management” group only consisted of patients with fetuses in the OP position during labor and not patients with fetuses delivering in the OP position at full dilation, a diagnosis of the type of posterior position was only made at birth. Patients presenting with a fetus with spontaneous rotation were therefore not taken into account. Finally, Le Ray et al. showed that manual rotation of a fetus in the posterior position in the second stage of labor (immediately at full dilation, at 1 or 2 h) significantly reduced the rate of instrumental vaginal delivery (23.2% vs 38.7% at 0, 1, and 2 h respectively,
p < 0.01 [
14]. However, no significant difference was found in terms of cesarean section rates. Many factors for bias, especially regarding selection, can be found in the study design, in comparing the practices between two different hospitals.
Therefore, it seems that manual rotation for posterior positions at full dilation is a simple and reproducible technique with presumably significant benefits in terms of spontaneous vaginal delivery rates. Some teams do not perform systematic rotations and prefer expectant management due to possible complications associated with attempting manual rotation, such as an abnormal fetal heart rate, cord prolapse, and emergency cesarean section [
16‐
18].
Benefits
Individual benefits for the experimental group (manual rotation) in comparison with the control group (expectant management) are:
The collective benefit is a reduced rate of instrumental vaginal deliveries and cesarean sections.
For the obstetricians, standardization of the technique is one of the primary expected benefits, along with Guidelines of Good Practice.
Trial design
This was a monocentric, open, comparative, randomized study with two balanced, parallel groups (1 to 1). This superiority study will take place in a type-3 maternity ward in a French University Hospital in which 4000 deliveries are performed per year.
The manual rotation group will be compared to the corresponding control group for which an expectant management strategy will be used.