Expert Commentary
Does mediolateral episiotomy reduce the risk of anal sphincter injury in operative vaginal delivery?
Yes.
LEARN TO PERFORM MIDCAVITY ROTATIONAL DELIVERIES
Bahl R, Van de Venne M, Macleod M, Strachan B, Murphy DJ. Maternal and neonatal morbidity in relation to the instrument used for midcavity rotational operative vaginal delivery: A prospective cohort study. BJOG. 2013;120(12):1526–1532.
Cesarean delivery during the second stage of labor used to be an uncommon event. It was said that if labor progressed adequately to achieve full cervical dilatation, a vaginal delivery should be achieved. Over the past few decades, however, the rate of cesarean delivery at full cervical dilatation has increased substantially, thereby contributing to the well-documented cesarean epidemic.
The most common indication for cesarean delivery during the second stage of labor is arrest of descent due to malposition of the fetal head, typically a transverse arrest. A number of alternatives to cesarean are available, all of which involve assisted rotation of the fetal head. Historical case series reporting increased neonatal morbidity have led to a reduction in the use of rotational forceps to facilitate this rotation. Attempted manual rotation and “rotational vacuum extraction” are now preferred, particularly by less experienced providers. Which of these three approaches is most effective is unknown.
Related article: You are the second responder to a shoulder dystocia emergency. What do you do first? Robert L. Barbieri, MD (Editorial; July 2011)
Details of the study
A prospective cohort study was carried out at two university hospitals in Scotland and England to compare maternal and neonatal morbidity associated with alternative techniques for midcavity rotational delivery. The choice of instrument was left to the provider.
Of the 381 nulliparous women who had an attempted midcavity rotational operative vaginal delivery, 163 (42.8%) underwent manual rotation followed by nonrotational forceps delivery, 73 (19.1%) had a rotational vacuum delivery, and 145 (38.1%) delivered with the assistance of rotational (Kielland) forceps.
Regardless of the instrument used, successful rotation and vaginal delivery were achieved in more than 90% of cases, with a cesarean rate of 4.2%, 6.8%, and 9.6% for manual rotation, vacuum, and rotational forceps, respectively (aOR, 0.39; 95% CI, 0.14–1.06). There were no significant differences in maternal complications (postpartum hemorrhage, third- and fourth-degree perineal lacerations) and neonatal morbidity (low cord pH, neonatal trauma, and neonatal intensive care unit admission) between the three instruments.
What this EVIDENCE means for practice
Midcavity rotational delivery can be achieved with a high degree of success and few adverse events in women who develop transverse arrest in the second stage of labor. Maternal and perinatal outcomes are comparable with rotational forceps, vacuum extraction, and manual rotation. With appropriate training, midcavity rotational delivery can be practiced safely, including the use of Kielland forceps.
SHOULD MIDWIVES PERFORM OPERATIVE VAGINAL DELIVERIES?
Black M, Mitchell E, Danielian P. Instrumental vaginal deliveries; are midwives safer practitioners? A retrospective cohort study. Acta Obstet Gynecol Scand. 2013;92(12):1383–1387.
In the United States, instrumental vaginal deliveries are performed only by physicians. In the United Kingdom, the opportunity to perform such deliveries has recently become available to midwives as well. Because midwives have less experience in performing surgical procedures, the question has arisen as to whether their complication rate is higher than that of physicians. Alternatively, because midwives typically are more patient than physicians and more reluctant to resort to obstetric interventions, it is possible that their complication rate may be lower.
Details of the study
To address this issue, Black and colleagues performed a retrospective cohort study of consecutive women who had a successful nonrotational instrumental vaginal delivery of a liveborn singleton infant outside of the operating room between June 2005 and June 2010 at Aberdeen Maternity Hospital in the United Kingdom.
Of the 2,540 women included in the final analysis, 330 (13%) were delivered by midwives and the remaining 2,210 (87%) by physicians—1,049 (41%) by junior doctors and 1,161 (46%) by more senior doctors. All midwives had undergone formal training at the University of Bradford. There were no differences between groups in demographic characteristics (maternal age, gestational age, parity, body mass index, or birth weight) or in the indications for instrumental delivery.
Major findings were that midwives were significantly less likely than junior and senior physicians to use forceps as the instrument of choice for delivery (OR, 0.6; 95% CI, 0.4–0.7). Mean blood loss was significantly lower in the midwife group (57 mL), although it is unlikely that this finding was clinically significant. There were no differences in severe perineal injury (third- or fourth-degree perineal lacerations), arterial cord pH, or postpartum hemorrhage.
A secondary analysis comparing the outcome of operative vaginal deliveries by trained midwives with the outcome by junior physicians alone produced almost identical results.
