What are the maternal and neonatal risks related to the occiput posterior (OP) or occiput transverse (OT) position in labor?
What are the indications for digital or manual rotation of OP/OT fetuses in labor?
How can fetal position accurately be diagnosed in labor?
What are the steps in performing a digital or manual rotation?
What are the risks related to rotational procedures?
A 24-y.o. African-American G1 at 39w6d is admitted in active labor at 4 cm after SROM for lightly meconium-stained amniotic fluid. EFW is 6.5 lbs. FHR tracing is found to be Category 2 for variable decelerations. She progresses to 8 cm, despite coupling and tripling of contractions. Pitocin augmentation is begun for protracted active phase. She dilates further to a rim, 90%, ‒1, with edema of the anterior cervix, but then remains a rim for 3 hours despite strong, regular contractions. Her anterior cervix becomes a stiff, edematous anterior lip. You find the fetus to be LOP, slightly asynclitic, and with the back on the right, confirmed by bedside ultrasound.
This patient has notable risk factors for fetal OP position in labor: she is African-American (thus with possible android or anthropoid pelvis) and is a nullipara. Her labor also has features consistent with an OP fetal position: earlier SROM, meconium, variable FHR decelerations, coupled/tripled contractions, protracted active phase requiring oxytocin, active phase arrest, and anterior cervical edema.
The occiput posterior (OP) and occiput transverse (OT) positions of the fetus in labor pose a notorious clinical challenge. (Throughout this chapter, whenever OP position is addressed, the reader should assume the inference of OT positions similarly.) Approximately 15% to 20% of fetuses present in labor in the OP position, and most of those rotate spontaneously. Roughly 5% remain OP. The right occiput posterior (ROP) position is two to five times more common than left occiput posterior (LOP), which is thought to be due to a combination of dextrorotation of the uterus, bladder in the right anterior and rectum in the left posterior portions of the maternal pelvis, and the dense liver on the right side of the fetus.
Occiput posterior positions are thought to account for 25% of all primary cesarean sections (C-sections). In the United States, nine of ten women who have had a primary C-section will have subsequent cesarean deliveries. Several studies demonstrate the effectiveness of manual rotation to increase rates of vaginal delivery in the setting of OP or OT fetal positions.1–3 The American College of Obstetricians and Gynecologists (ACOG), in concert with the Society for Maternal-Fetal Medicine (SMFM), released a joint Obstetric Care Consensus in 2014 on Safe Prevention of the Primary Cesarean Delivery.4 Prior to a decision for C-section or operative vaginal delivery, a trial of manual rotation of the OP vertex in the second stage is suggested as a reasonable alternative. The Society of Obstetricians and Gynecologists of Canada ...