Análisis de los factores relacionados con un mayor rendimiento de la versión cefálica externa en la población gestante

Resum

BACKGROUND: External Cephalic Version (ECV) is a procedure for modifying the fetal position and achieving a cephalic presentation. The purpose of the ECV is to offer a chance for cephalic delivery which is safer than breech delivery or cesarean section. A breech presentation occurs in 5% of all pregnant women at 36 gestation weeks. During the ECV, maternal abdomen is kneaded by an operator who tries to roll the baby. Some adverse events may arise after ECV such as uterine contractions, premature rupture of membranes, abdominal pain, vaginal bleeding, non-reassuring fetal heart rate pattern, cord prolapse or abruptio placentae. Many factors are associated with better ECV efficiency and security. Some of them are non-modifiable like multiparity, previous cesarean birth, ethnicity, placental location, body mass index or amniotic fluid volume. However, many of them are clinically much important and they are classified as modifiable such as use of analgesia, anesthetic agents, tocolytic drugs, maternal position or bladder volume. MATERIAL AND METHODS: An observational longitudinal ambispective cohort study was carried out at the Obstetric Department of the ‘Virgen de la Arrixaca’ University Hospital in Murcia (Spain), between January 2014 and May 31st 2021. All the participants were pregnant woman with non-cephalic presentation with no contraindication for vaginal delivery such as: abruptio placentae, eclampsia, severe preeclampsia, placenta previa, or Rh sensitization. Patients were offered the ECV during the third-trimester evaluation between 32 and 36 gestation weeks. The procedure was carried out in the operating room in the presence of a midwife and an anesthesiologist. Just before the ECV, 0.2 mg/min of ritodrine was administered for 30 minutes. Paracetamol 1 gram was used as intravenous analgesic agent. The procedure was performed under sedation, generally with propofol. An initial dose of 50 mg was administered intravenously and additional boluses of 10-20 mg was administered when the operator required them. Although propofol was the most common sedation drug used, it depended on the anesthesiologist criteria. Maternal anthropometrics, obstetric history, ultrasound test, procedure operator, ECV results, adverse events and delivery data were registered. It was analyzed the role of Propofol as sedative agent, the factors influencing in ECV success rate and the role of super-specialization in ECV. RESULTS: In our first publication, a descriptive analysis of type of delivery after ECV and a detailed protocol description were shown. The ECV success rate was 82.5% and the complications rate was 5.9%. Multiparity was associated with a higher ECV success rate (OR 3.12; 95%CI 1.52-6.45), while BMI (OR 0.92; 95%CI 0.86-0.92) reduced the success rate. After a successful ECV, the spontaneous birth rate was 52.1%, the operative delivery rate was 25.7% and the urgent cesarean birth rate was 22.2%. Compared with general population, an increase of 6.99% in the operative delivery rate after a successful ECV (OR 1.64; 95%CI 1.22-2.17) was observed. In our second publication, the ECV outcomes when propofol was used as sedative agent were analyzed. The ECV success rate (61.1%) and complications rate (11.5%) was slightly worse than the previous study. The propofol mean dose was 156.1 mg (SD 6.1). A clinically relevant hypotension was observed in 18.3% of the procedures. In the third publication, the role of the operator in the ECV results was determined. For three months, all the procedures were performed by two seniors obstetricians specialized in obstetrical care with 15 years of experience in delivery room (Group B). These seniors’ colleagues were not involved in the dedicated team for ECV. These procedures were compared with those performed by two of the four experienced obstetricians who composed the super-specialized dedicated team for ECV (Group A). More than seven hundred procedures have been carried out by this team. The ECV success rate of super-specialized team was 74.0% vs 47.2% in Group B (OR 3.18; 95%CI 1.4-7.2). The greatest increase in the success rate of ECV was seen in nulliparas, from 38.5% Group B to 69.1% in super-specialized team (OR 3.57; 95%CI 1.33-9.83). The complications rate was 9.3% in the super-specialized group vs 22.2% in Group B (OR 0.36; 95%CI 0.14-0.91). CONCLUSIONS: ECV is an effective procedure for achieving a cephalic presentation. Furthermore, ECV results and complications when the sedation with propofol and tocolysis with ritodrine are used, are similar to other analgesic methods. Lastly, super-specialization in ECV improves the success rate and reduce the complications rate.