For assisted vaginal delivery, does the use of forceps or vacuum devices result in lower morbidity for the mother and newborn?
Use of forceps is more likely to result in a vaginal delivery than use of vacuum devices (relative risk [RR] = 1.5; 95% confidence interval [CI], 1.1 to 2.2), but has a higher rate of perineal trauma, tears, pain, and incontinence, and a trend toward more cesarean deliveries. Use of metal-cup vacuum devices is more likely to result in a vaginal delivery than use of soft-cup devices, but is more likely to cause neonatal scalp injury and cephalohematoma. (Strength of Recommendation = A, based on consistent, good-quality patient-oriented evidence)
Assisted vaginal deliveries are recommended for fetal distress, failure to deliver after a prolonged second stage of labor, or maternal factors that would make pushing dangerous, such as exhaustion or medical problems. The choice of instrument depends on factors such as the training of the physician, fetal position, and the degree of anesthesia. Vacuum extraction does not require as much anesthesia for the mother as forceps.1
To determine the safest delivery method for the mother and newborn, the authors of this Cochrane review searched for randomized controlled trials comparing methods of assisted vaginal delivery at term. The authors found 32 studies including 6,597 women. Seventeen of the studies compared types of vacuum devices, and 13 studies compared forceps with vacuum devices. Although the failure rate was lower with forceps than with vacuum devices, third- and fourth-degree perineal tears were more common with forceps (RR = 1.9; 95% CI, 1.6 to 3.9). Facial injuries in newborns were also more common with forceps (RR = 5.1; 95% CI, 1.1 to 23). There were no differences between forceps and vacuum devices in Apgar score, shoulder dystocia, need for intubation, severe morbidity, death, or use of maternal analgesia. Compared with soft-cup vacuum devices, use of metal cups was more likely to result in a vaginal delivery but had higher rates of neonatal bruising, cephalohematoma, and scalp injury.
There are risks and benefits with different assisted vaginal delivery methods, with no clear superiority of one device over another. However, this review supports the use of vacuum extraction with a soft cup as the first-line method because of its lower risk of harming the newborn. [ corrected]