Data from the last 3 decades confirm that the rate of operative vaginal deliveries is decreasing in North America.1–4 The United States, Canada, Eastern Europe, and South America prefer the use of forceps extractions. The vacuum is the instrument of choice in Western Europe, Asia, Israel, and the Middle East.5
It has been reported that 60% of residency programs in the United States perform less than 10% of their total deliveries with the assistance of the vacuum or forceps.6 At our institution, the use of vacuum has increased whereas forceps use has decreased during the past 10 years. Six percent of the total deliveries are operative vaginal deliveries. Review of the literature suggests differential maternal and neonatal complications between forceps and vacuum assisted deliveries.7–11 The purpose of this study was to estimate the differences in immediate maternal and neonatal effects of forceps and vacuum-assisted deliveries in a community-based teaching hospital with a residency program in obstetrics and gynecology.
MATERIALS AND METHODS
We performed a record review of all forceps and vacuum-assisted deliveries that occurred from January 1, 1998, through August 30, 1999, at Winthrop-University Hospital. The study was approved by the institutional review board. The deliveries were performed by a senior resident under the supervision of an attending physician. Maternal demographics recorded included age, parity, and gestational age. Delivery characteristics recorded included indication for the use of an instrument, use of oxytocin, fetal position and station, change in instrument, delivery by cesarean, and type of anesthesia. Maternal outcomes of interest were the use of episiotomy, lacerations sustained, and presence of vulvovaginal hematomas. The delivery information was entered in the medical record by the physician performing the delivery.
Neonatal outcomes of interest were birth weight, Apgar scores, neonatal intensive care unit (NICU) admissions, cephalohematomas, instrument marks and bruising, and caput and molding. The pediatricians who examined the newborns were aware of the delivery history.
Statistical analysis included Student t test for continuous variables and χ2 test for categorical variables. The Fisher exact test was used when the expected cell frequencies were equal to or less than 5. Multivariable logistic regression was performed to examine the role of vacuum or forceps use on selected outcomes: major perineal/vaginal lacerations, periurethral tears, cephalohematomas, and instrument marks and bruising controlling for confounding variables. P < .05 was considered statistically significant. Statistical analyses were performed by using True EPISTAT (Epistat Services, Richardson, TX).
Of 8,241 deliveries during the study period, 1,989 were cesarean deliveries for a rate of 24.1%. The primary cesarean delivery rate was 14.9%. Of 508 operative vaginal deliveries (6.2% of all deliveries), 200 (39.4%) were forceps and 308 (60.6%) were vacuum assisted. There were no differences between the forceps and vacuum-assisted groups in maternal age (31.2 ± 5.1 years versus 31.6 ± 5.0 years; P = .89), parity (75.5% versus 68.5% primiparous; P = .10), and gestational age (39.3 ± 1.8 weeks versus 39.6 ± 1.5 weeks; P = .68). All operative vaginal deliveries were of 34 weeks or more of gestation.
Forceps were used more often than the vacuum for prolonged second stage of labor (14% versus 5.2%; P = .001). The differences in the use of oxytocin, success in operative delivery, rate of instrument changes, and cesarean delivery were not significant between the 2 groups. There was a higher rate of epidural (90.5% versus 82.8%; P = .02) and pudendal (13% versus 1.9%; P < .001) anesthesia in the forceps group than in the vacuum-assisted group. Frequently, women were given another anesthetic after an epidural (Table 1). Ninety five percent of the instrumental deliveries were completed with 1 instrument. Twenty-two women (4.3%) required a change of instrument to complete the delivery whereas only 2 women required cesarean delivery. Forceps were applied more often when the fetal position was occiput anterior or posterior whereas the vacuum was used more frequently with occiput transverse positions. There was a trend for a more frequent use of forceps than vacuum at the outlet, whereas vacuum was applied more frequently than forceps at midstation but the differences were not statistically significant (Table 1).
There were more episiotomies performed in the forceps (90.5% versus 81.8%; P = .01) than in the vacuum-assisted group. There was a greater incidence of maternal third- and fourth-degree perineal lacerations (44.4% versus 27.9%; P < .001), and vaginal lacerations (19% versus 9.7%; P = .004) with the use of forceps. However, more periurethral lacerations were seen in the vacuum-assisted group (4.2% versus 0.5%; P = .026) than in the forceps group. More women in the vacuum-assisted group were free of injury to the perineum or vagina than in the forceps group, although the difference was not statistically significant (38.3% versus 30%; P = .07; Table 2).
Birth weights, Apgar scores, and NICU admissions were similar between the 2 groups. More instrument marks and bruising (36.5% versus 10.7%; P < .001) were found in the neonates delivered by forceps. However, there was a greater incidence of cephalohematomas (20.5% versus 12.5%; P = .03), and caput and molding (28.2% versus 13.5%; P < .002) in the neonates who were delivered by the assistance of the vacuum (Table 3).
Using multivariable logistic regression analysis and vacuum as the reference group, forceps use (odds ratio [OR] 1.85; 95% confidence interval [CI] 1.27, 2.70; P = .001) was independently associated with an increase in major perineal and vaginal tears. In addition, a birth weight of 4,000 g or more (OR 2.09; 95% CI 1.06, 4.10; P = .03) and use of episiotomy (OR 2.22; 95% CI 1.22, 4.05; P = .01) were independently associated with major tears (Table 4). When neonatal outcomes were evaluated, the use of forceps was associated with an increase in instrument marks and bruising (OR 4.63; 95% CI 2.90, 7.41; P < .001; Table 5) and a decrease in cephalohematomas (OR 0.49; 95% CI 0.29, 0.83; P = .007; Table 6).
One hundred eighty-one women in the forceps group and 252 women in the vacuum group had an episiotomy performed. This subgroup of women was analyzed for injuries. We found a greater incidence of fourth-degree perineal lacerations (12.2% versus 4.8%; P = .005) and vaginal lacerations (18.8% versus 9.5%; P = .005) with the use of forceps. There were no significant differences in the incidence of third-degree perineal lacerations between the 2 groups (33.7% forceps versus 27.4% vacuum; P = .16). However, more periurethral lacerations were seen in the vacuum-assisted group (2.4% versus 0; P = .04) than in the forceps group. More instrument marks and bruising (37.6% versus 10.3%; P < .001) were found in the neonates delivered by forceps. However, there was a greater incidence of cephalohematomas (21.4% versus 13.8%; P < .04) and caput and molding (33.7% versus 16%; P < .001) in the neonates who were delivered by the assistance of the vacuum.
There were 151 nulliparas in the forceps group and 211 nulliparas in the vacuum group. Forceps were used more often than vacuum for prolonged second stage of labor (15.9% versus 6.6%; P = .008). There was a higher rate of epidural (95.4% versus 86.7%; P = .01) and pudendal (12.6% versus 1.4%; P < .001) anesthesia in the forceps group than in the vacuum-assisted group. The difference in episiotomy use (92.7% versus 89.6%; P = .31) and in the number of women without injury (42.5% versus 37.9%; P = .28) was not significant between the forceps and vacuum groups. We found a greater incidence of fourth-degree perineal lacerations (12.6% versus 4.7%; P = .007) and vaginal lacerations (17.2% versus 10.4%; P = .06) with the use of forceps. There were no significant differences in the incidence of third-degree perineal lacerations (33.8% forceps versus 27.5% vacuum; P = .2). However, more periurethral lacerations were seen in the vacuum-assisted group (4.3% versus 0; P = .01) than in the forceps group. More instrument marks and bruising (39.1% versus 10.9%; P < .001) were found in the neonates delivered by forceps. However, there was a greater incidence of cephalohematomas (22.7% versus 14.6%; P < .07) and caput and molding (31.3% versus 13.9%; P < .002) in the neonates who were delivered by the assistance of the vacuum.
Twenty-two (4.3%) vaginal deliveries were completed after there was a change of instrument. Seventeen (77.3%) women were nulliparas. All 22 women had an episiotomy performed. Ten (45.5%) women had a third- or fourth-degree perineal laceration, 4 (18.2%) had vaginal lacerations, and 1 (4.5%) woman sustained a periurethral tear. Five (22.7%) neonates had cephalohematomas, 6 (27.3%) had instrument marks and bruising, and 8 (36.4%) had caput and molding. One neonate required admission to the NICU.
This study was designed to estimate the immediate maternal and neonatal effects of forceps and vacuum-assisted deliveries in a community hospital with a residency program in obstetrics and gynecology. Although there was a greater use of episiotomies in the forceps group, women in this group sustained more third- and fourth-degree perineal and vaginal lacerations than women in the vacuum-assisted group. This is in agreement with the work of Bofill et al8 reporting that vacuum-assisted deliveries were associated with a lower rate of episiotomy, third-and fourth-degree perineal lacerations, and vaginal lacerations. Other studies, although not commenting on the use of episiotomies, also showed that maternal soft tissue injuries in the form of vaginal lacerations or third- or fourth-degree lacerations were more common in the women delivered with the use of forceps.7,9–11 Ecker et al12 reviewed the use of episiotomy for operative vaginal delivery at their institution between 1984 and 1994. Interestingly, the use of episiotomy fell significantly whereas there was an increase in the rate of vaginal lacerations and no significant change in the rate of third-degree lacerations with the use of forceps or vacuum. In addition, there was a significant decrease in the rate of fourth-degree lacerations with forceps use but not with vacuum.12
Of interest is our finding of more periurethral tears in the vacuum-assisted group than in the women delivered with the assistance of forceps. More periurethral tears were seen in the vacuum-assisted group even with the performance of an episiotomy, suggesting the performance of the episiotomy was not protective. Bofill et al8 found more periurethral tears in the women delivered by vacuum, although the difference was not statistically significant (P = .08).
Epidural anesthesia was used very frequently in both groups but more so in the forceps group. It is possible that in our institution physicians are more likely to use forceps in women who have received an epidural. Generally, epidural anesthesia has been associated with longer first and second stages of labor.13 The effect of different epidural techniques on the second stage of labor needs to be studied more carefully. Perhaps, a stricter definition of prolonged second stage for nulliparas and multiparas with or without epidural anesthesia should be used and studied prospectively.
At our institution, 95% of the instrumental deliveries were completed with 1 instrument. In the study by Bofill et al,8 93% of the women were delivered with the intended instrument. In the study by Johanson et al,11 85% of the women in the vacuum group and 90% in the forceps group were delivered by the assigned instrument. It is possible that the high rate of success with 1 instrument was the result of the appropriate selection of the instrument. There are significant concerns related to maternal and neonatal injury when more than 1 instrument is used. In these situations, we found the rates of maternal and neonatal injury to be similar to the rates of the instrument causing the highest injury when only 1 instrument is used. We did not encounter serious injury but, in a retrospective review, Gardella et al14 found that the sequential use of vacuum and forceps was associated with increased rates of intracranial hemorrhage, brachial plexus, facial nerve injury, seizure, depressed 5-minute Apgar score, assisted ventilation, fourth-degree and other lacerations, hematoma, and postpartum hemorrhage.
Neonates in the forceps group had a greater incidence of instrument marks and bruising, whereas neonates in the vacuum-assisted group had more cephalohematomas. These findings are consistent with the studies of Johanson et al,8 Bofill et al,9 and Wen et al.11
At our institution, the use of vacuum has increased whereas forceps use has decreased during the past 10 years. Our institution's 6% rate of operative vaginal deliveries is comparable with 36% of the North American residency programs.6 Fifty-nine percent of our operative vaginal deliveries were accomplished with the assistance of the vacuum. Twenty-one percent of the residency programs use vacuum in 51% to 75% of their operative vaginal deliveries, whereas 68% of the residency programs prefer forceps and use vacuum less than 50% of the time.6 In many parts of the country, vacuum use has surpassed forceps delivery.15 We anticipate the rate of operative vaginal deliveries to continue to decrease because there is less training of residents as the result of a shortage of skilled obstetricians, the cesarean delivery rate increases, and the medical malpractice environment worsens.
Residents are assigned to the deliveries while being supervised by attending physicians with different degrees of expertise. Although vacuum extraction clearly causes less significant maternal trauma, the incidence of cephalohematomas is increased. Even although cephalohematomas are not considered serious and the majority resolve without much consequence, subgaleal and subarachnoid hemorrhages are rare but significant injuries associated with the vacuum extractor. Instruments used to accomplish vaginal delivery must be used with caution and the delivery supervised by trained personnel. Our findings should assist obstetricians in selecting an instrument for an operative vaginal delivery and in counseling the patient regarding the risks and benefits of alternative approaches.
The limitations of our study were related to its retrospective nature and the lack of randomization. Delivery documentation was incomplete. Newborn examinations were performed by physicians who knew the delivery information therefore the exams may have been “selective” rather than “objective.” More information related to the use of regional anesthesia would have been beneficial in understanding its relation to the second stage of labor. Despite their limitations, our findings are in agreement with other prospective studies.
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