A commentary on ACOG Practice Bulletin Number 154: Operative Vaginal Delivery by Charles J Lockwood, MD, MHCM.
COMMITTEE ON PRACTICE BULLETINS-Obstetrics Practice Bulletin No. 154: Operative Vaginal Delivery. November 2015 (Replaces Bulletin No. 17, June 2000). American College of Obstetricians and Gynecologists. Obstet Gynecol. 2015;126:e56-65. Full text of ACOG Practice Bulletin available to ACOG members at http://www.acog.org/Resources_And_Publications/Practice_Bulletins/Committee_on_Practice_Bulletins_--_Obstetrics/Operative_Vaginal_Delivery.
OPERATIVE VAGINAL DELIVERY Despite significant changes in management of labor and delivery over the past few decades, operative vaginal delivery remains an important component of modern labor management, accounting for 3.30% of all deliveries in 2013 (1). Use of obstetric forceps or vacuum extractor requires that an obstetrician and obstetric care provider be familiar with the proper use of the instruments and the risks involved. The purpose of this document is to provide a review of the current evidence regarding the benefits and risks of operative vaginal delivery.
Dr. Lockwood is Senior Vice President, USF Health and Dean, Morsani College of Medicine, University of South Florida, Tampa, FL, and Editor in Chief of Contemporary OB/GYN.
When I was a resident I performed more than 250 operative vaginal deliveries, mostly with forceps, and many after rotation. I suspect many practitioners of my generation compiled similar numbers during their training. Well, times have changed. Whereas in 1990 slightly more than 9% of livebirths resulted from either forceps delivery (5.11%) or vacuum extraction (3.9%), by 2014 only 3.21% of livebirths resulted from operative vaginal delivery and forceps accounted for less than 20% of these births (0.57% of all live births).1
The latest ACOG Practice Bulletin on this subject serves as an excellent summary of the indications, prerequisites, advantages, and overall safety of this increasingly lost art.2
Operative vaginal delivery is indicated for both maternal and fetal reasons. The former include exhaustion and ineffectual pushing in the second stage of labor as well as various medical and obstetrical factors requiring an expedited second stage. Such factors include preexisting cardiovascular disease, deteriorating medical conditions (eg, hypertension, sepsis), prolonged second stage of labor, arrest of descent or the need to rotate the fetal head to effect vaginal delivery. In cases of nonreassuring fetal heart rate (FHR) tracings, operative vaginal delivery may not only obviate the short- and long-term maternal morbidities of cesarean delivery but avoid progressive fetal ischemia.
While the Practice Bulletin retains the traditional classification system for outlet, low and mid-forceps deliveries (see Box 2), ACOG points out that in general, the lower the fetal head in the pelvis and the less rotation required, the less the risk of maternal and fetal injury. Vaginal birth is more likely to be achieved with forceps than with vacuum extraction, but the former has about twice the rate of associated 3rd- or 4th-degree perineal tears. However, despite this higher rate of perineal trauma, when compared with outcomes for cesarean delivery, forceps delivery was not associated with higher rates of pelvic floor or sexual dysfunction in primiparous women 1 year postpartum.3 In addition, no differences in bowel or bladder function were found between women delivered by forceps versus vacuum extraction at 5 years.4
The Practice Bulletin does caution against the routine use of episiotomy with operative vaginal delivery given its association with perineal trauma.
Forceps delivery has been associated with fetal facial lacerations and nerve palsy, ocular trauma, skull fractures and intracranial hemorrhage, while vacuum extraction has been linked to fetal scalp lacerations, cephalohematoma formation, subgaleal and retinal hemorrhage. Fortunately, all these risks are low. While neurological complications occur in 1 of 220 to 385 infants having operative vaginal deliveries, these rates must be compared to those delivered by, often emergent, cesarean section. For example, using seizure, intraventricular hemorrhage, and subdural hemorrhage as collective indicators of adverse neurologic outcome, forceps deliveries were associated with a reduced risk of such outcomes compared with both vacuum extraction (odds ratio 0.60; 95% CI: 0.40-0.90) and cesarean delivery (OR 0.68; 95% CI: 0.48-0.97).5
Similarly, while vacuum deliveries were associated with higher rates of scalp laceration, fracture, and brachial plexus injury compared with cesarean, they were not associated with excess neurological injury. Indeed, Walsh and associates noted that when compared with cesarean delivery in the 2nd stage of labor, operative vaginal delivery accrued similar rates of neonatal death and encephalopathy.6 This study found that the absolute risk of neonatal mortality from intracranial hemorrhage was 3 to 4 per 10,000 for both instruments. Long-term neurological outcomes also appear comparable among infants delivered spontaneously versus by operative vaginal delivery.7
The Practice Bulletin also addresses the contentious issue of operative vaginal delivery of the macrosomic infant. The authors note that the risk of persistent injury is comparable between macrosomic infants who were delivered spontaneously compared with operative vaginal delivery, suggesting that it is the macrosomia rather than the mode of vaginal delivery which is the culprit. The Practice Bulletin concludes that “judicious use of operative vaginal delivery for infants with suspected macrosomia is not contraindicated.” The authors do point out that the adequacy of the pelvis and the progress of labor, especially the 2nd stage, should be carefully considered in this setting and preparations made for a possible shoulder dystocia.
Among the recommendations made by ACOG are:
• Operative vaginal delivery is contraindicated if the fetal head is unengaged or its position is unknown, or if a fetal demineralizing or bleeding condition is suspected; and it should be performed only by experienced obstetricians with the appropriate hospital privileges.
• While cesarean delivery after “failed” operative vaginal delivery in the setting of a nonreassuring FHR tracing is associated with increased neonatal morbidity, this risk must be weighed against the benefits of an expedited delivery when operative vaginal delivery is successful in this setting. On balance, ACOG prudently opines that “A trial of operative vaginal delivery is an appropriate option [when] the obstetrician [...] feels the chances of success are high, but must be prepared to abandon the attempt if appropriate descent does not occur.”
• Because of incremental fetal and maternal risk, sequential use of vacuum extraction and forceps or vice versus should not be routinely performed.
• While the risk of cephalohematoma increases with the duration of vacuum application, particularly after 5 minutes, release of vacuum pressure between contractions does not appear to be associated with improved outcomes.
• Forceps rotations to effect delivery are not linked to excess neonatal neurological morbidity. Furthermore, because forceps rotation of a fetus in a persistent occiput posterior position to an occiput anterior position may reduce maternal perineal laceration, it seems reasonable to attempt manual or forceps rotation of fetuses in certain such circumstances.
• Vacuum extraction is discouraged at gestational ages less than 34 weeks.
• Neonatal providers should be made aware of an operative vaginal delivery to facilitate observation for related complications.
ACOG ABSTRACT REFERENCE
1. Martin JA, Hamilton BE, Osterman MJ, Curtin SC, Matthews TJ. Births: final data for 2013. Natl Vital Stat Rep 2015;64:1-65. (Level II-3)
1. Hamilton BE, Martin JA, Osterman MJ, Curtin SC, Matthews TJ. Births: Final Data for 2014. Natl Vital Stat Rep. 2015 Dec;64(12):1-64.
2. Operative vaginal delivery. Practice Bulletin No. 154. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2015;126:e56–65.
3. Crane AK, Geller EJ, Bane H, Ju R, Myers E, Matthews CA. Evaluation of pelvic floor symptoms and sexual function in primiparous women who underwent operative vaginal delivery versus cesarean delivery for second-stage arrest. Female Pelvic Med Reconstr Surg. 2013 Jan-Feb;19(1):13-6.
4. Johanson RB, Heycock E, Carter J, Sultan AH, Walklate K, Jones PW. Maternal and child health after assisted vaginal delivery: five-year follow up of a randomised controlled study comparing forceps and ventouse. Br J Obstet Gynaecol. 1999 Jun;106(6):544-9.
5. Werner E F, Janevic TM, Illuzzi J, Funai EF, Savitz DA, Lipkind HS. Mode of delivery in nulliparous women and neonatal intracranial injury. Obstet Gynecol. 2011 Dec;118(6):1239-46.
6. Walsh CA, Robson M, McAuliffe FM. Mode of delivery at term and adverse neonatal outcomes. Obstet Gynecol. 2013 Jan;121(1):122-8.
7. Wesley BD, van den Berg BJ, Reece EA. The effect of forceps delivery on cognitive development. Am J Obstet Gynecol. 1993 Nov;169(5):1091-5.