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Abstract

After centuries of use in obstetrics, have forceps and vacuum deliveries become a dying art? Contemporary trends in operative vaginal delivery show increasing numbers of vacuum deliveries and decreasing numbers of forceps deliveries worldwide. Primary drivers of such trends include concerns over neonatal and maternal safety as well as fewer clinicians skilled in forcep use. Current literature reports a comparable efficacy rate for the two instruments, as well as a decrease in maternal morbidity compared with cesarean section. It has also been suggested that the neonatal morbidity once associated with operative vaginal delivery may actually be a function of an abnormal labor process itself, rather than a consequence of an operative vaginal intervention. Both the American College and the Royal College of Obstetricians and Gynecologists continue to support the use of both vacuum and forceps and strongly encourage residency programs to incorporate the teaching of these skills into their curricula.

Keywords

forceps manual rotation operative delivery

The concept of operative vaginal delivery dates back to 1500 BC, from when writings and pictures describing primitive forceps have been found. The invention of the precursor to modern forceps is credited to Peter Chamberlin in approximately 1600. This precursor has been modified and reinvented over the years, and at this time, over 700 types of obstetrical forceps have been described throughout history [1]. The vacuum extractor was first described by James Yonge in 1705 and was popularized in Europe by Malmstrom in 1954. This instrument has also undergone many modifications over the years, most notably the evolution of the metal cup to the silastic and rubber cup, to what is now the modern vacuum extractor [2].

Current trends show that the cesarean delivery rate has increased over the past decade (30.3% in the USA in 2005 and 21.3% in England in 2001) while the operative vaginal delivery rate has decreased overall, although both rates vary enormously around the world [3,4]. Of these operative vaginal deliveries, the percentage of forceps deliveries has decreased while the percentage of vacuum deliveries has increased. Concerns over neonatal and maternal safety have been the primary drivers of these trends, as well as fewer clinicians who are trained in using forceps who are able to teach residents. Professional liability has also had an impact, as birth injuries associated with delayed cesarean section and difficult operative deliveries are a common cause of obstetric malpractice suits [5]. In the 2006 American College of Obstetricians and Gynecologists (ACOG) Survey on Professional Liability, 37.1% of obstetricians reported increasing their rate of cesarean sections due to fear of litigation [6]. This article aims to discuss the current indications and techniques of operative vaginal delivery with forceps and vacuum extractors; review the efficacy data for both forceps versus vacuum deliveries and for operative vaginal delivery versus normal spontaneous vaginal delivery versus cesarean delivery; and review current literature evaluating both short- and long-term maternal and neonatal outcomes with both forceps and vacuum deliveries.

Indications & prerequisites for operative vaginal delivery

According to both the ACOG and Royal College of Obstetricians and Gynecologists (RCOG) practice bulletins, the indications for operative vaginal delivery can be divided into fetal, maternal and inadequate progress as outlined in Box 1. These indications only apply when the fetal head is engaged, the cervix is fully dilated, the membranes are ruptured and the fetal head position is identified [7,8]. None of these indications are absolute and each case should be evaluated on an individual basis.

Prior to attempting an operative vaginal delivery, the fetal position, presentation, lie and any degree of asynclitism should be assessed. Clinical pelvimetry should also be performed to evaluate the adequacy of the maternal pelvis. The patient should be properly placed in the dorsal lithotomy position, adequate anesthesia provided and the bladder drained. Operative vaginal delivery should only be attempted in a setting where anesthesiologists and operating rooms are readily available should cesarean section become the next necessary resort. The criteria for outlet, low-and mid-pelvic operative deliveries are outlined in Box 2 [7,8].

Box 1.

Indications for operative vaginal delivery.

Fetal

– Suspicion of immediate or potential fetal compromise

Maternal

– Shortening of the second stage for maternal benefit (i.e., inadequate expulsive efforts, or medical contraindications to valsalva)

Inadequate progress

– Nulliparous patients: lack of continuing progress for 3 h with regional anesthesia, or 2 h without regional anesthesia

– Multiparous patients: lack of continuing progress for 2 h with regional anesthesia, or 1 h without regional anesthesia

Operative vaginal delivery techniques

Vacuum extraction

The basic elements of a vacuum extractor include the attachment device, which is applied to the presenting part, the connecting tube, the handle and the vacuum-generating device, which may be a separate entity or incorporated into the handle. In the case of the modern Kiwi™ OmniCup vacuum extractor, a traction force indicator is also present to assist the operator in monitoring and controlling the amount of traction force exerted on the fetal scalp. The attachment cup should be placed over the sagittal suture, approximately 2–3 cm in front of the posterior fontanelle. This promotes flexion of the fetal cervical spine. It is imperative to check for entrapment of maternal soft tissue prior to initiating the vacuum. The appropriate force to achieve a successful vacuum extraction is 0.7 ± 0.1 kg/cm². Detachment of the vacuum device tends to occur with a force less than 0.6 kg/cm², whereas there is an increased risk of fetal scalp and cerebral trauma without added benefit to the procedure with forces greater than 0.8 kg/cm². Traction should only be applied to the apparatus in conjunction with uterine contractions and maternal efforts therefore augmenting maternal expulsive forces. Manual torque aimed at rotating the presenting fetal part should be avoided, as it is linked with higher rates of fetal scalp lacerations. Proper technique includes only steady traction in the line of the birth canal [2]. A technical issue as to whether the vacuum should be reduced between contractions to prevent fetal scalp injury has been raised. In 1997, Bofill et al. performed a randomized, controlled trial involving 322 patients comparing continuous vacuum suction during and between contractions to intermittent vacuum suction with contractions only. There was no difference in efficacy (continuous: 93% success vs intermittent: 94% success) and no difference in time required for delivery (continuous: 167.6 s vs intermittent: 167.1 s; p = 0.97). There was an 11.5% rate of neonatal cephalhematoma, although there was no significant difference between the two groups (p = 0.686) [9]. This study supports the claim that there is no advantage to continuous vacuum suction to prevent loss of fetal station as well as no difference in maternal or fetal outcome with either continuous vacuum or intermittent vacuum reduction between contractions. Operator preference may be appropriate in choosing which technique to employ.

While there is little objective evidence, there appears to be a strong consensus on the appropriate number of pulls, number of detachments and total duration tolerated prior to abandoning the procedure. Both the ACOG and the RCOG recommend that if either progressive descent of the fetal head does not occur with each pull or delivery is not imminent following three pulls of a correctly applied instrument by an experienced operator, the procedure should be abandoned and delivery via cesarean section should occur [7,8]. Cord blood gases should be obtained from each neonate exposed to either a successful or abandoned operative vaginal delivery. The pediatric team caring for the neonate should always be alerted that a vacuum device has been used so they can properly monitor for signs and symptoms of vacuum-related injury.

Box 2.

Classification of operative vaginal deliveries.

Outlet

Fetal scalp visible at introitus without separating the labia

Fetal skull has reached the pelvic floor

Sagittal suture is in the AP diameter or right or left occiput anterior or posterior position

– Fetal head is at or on perineum

– Rotation does not exceed 45°

Low

Leading point of the fetal skull is at station 2 cm or more and not on the pelvic floor

Subtypes

– Rotation 45° or less

– Rotation greater than 45°

Mid-pelvis

Station is above 2 cm but head is engaged

There are a few circumstances in which vacuum-assisted vaginal delivery should be avoided. These include a fetus with a known bone demineralization or bleeding disorder, an unengaged fetal head and a nonvertex presentation. In cases of prematurity less than 34 weeks or suspected macrosomia, risks and benefits should be carefully considered before attempting vacuum delivery [2,7,8]. These situations may present an increased risk for both fetal head trauma and/or a failed vacuum delivery attempt.

Forceps delivery

The same prerequisites, indications and contraindications as discussed above apply for forceps-assisted vaginal deliveries, although intracranial trauma associated with prematurity is less of a concern. According to most authorities, forceps are the preferred instrument for operative deliveries performed at less than 34 weeks gestation. As always, each case must be individualized and take into account both maternal and fetal considerations. The first crucial step in a forceps delivery is for the operator to determine the position of the fetal head. By correctly identifying this position, the least amount of force necessary to achieve descent of the fetal head in a flexed position needs to be applied. Correct application of the forceps blades is essential prior to applying traction. The blades should be placed so that they lie evenly against the sides of the fetal head, reaching to and beyond the malar eminences. They should uniformly cover the space between the fetal orbits and ears. Pressure from the blades ought to be evenly distributed and transmitted symmetrically to the fetal intracranial structures [1].

Traction should always be in the axis of the pelvis. As the fetal head descends, the line of traction should move forward in a curved line following the curve of the sacrum and then upward through the pelvic outlet. The amount of force should be the least amount necessary to achieve head descent (i.e., a maximum of 45 lbs in a primiparous patient and 30 lbs in a multiparous patient) [1]. Traction should be accomplished with a steady pull that is gradually increased in intensity, sustained for a definite interval, and then gradually relaxed. As with vacuum extraction, the pull on the instrument should coincide with uterine contractions. Again, there is little objective evidence to direct the number of pulls on the instrument or the total duration of the procedure tolerated prior to abandonment.

Midforceps rotational deliveries, once routinely performed for rotation of the fetal head greater than 45 degrees, are becoming rare in current obstetrics. Again, this is mainly driven by a decreased number of experienced operators and an increase in medical legal concerns. As a result of the extremely low number of rotational deliveries being performed, there are no recent studies examining safety and efficacy data. A retrospective study from 1990 comparing midforceps rotational delivery with cesarean delivery revealed an increase in maternal morbidity with cesarean delivery [10]. Similar findings were also reported in a 1984 retrospective analysis, which also revealed no difference in neonatal outcome when comparing rotational delivery with cesarean section [11]. Again, long-term follow-up data are limited but do not suggest any difference in outcome comparing infants delivered by rotational forceps versus cesarean section [12,13]. ACOG recommends that midforceps rotational deliveries should still have a role in modern obstetrics, although they should only be attempted by experienced operators in carefully selected circumstances [7].

Efficacy of operative vaginal delivery

One of the ultimate questions posed is how efficacious is operative vaginal delivery versus cesarean section? In a randomized prospective study by Johansen et al. comparing the success of vacuum and forceps-assisted deliveries, there was a 90% forceps success rate and an 85% vacuum success rate [14]. This trend is also supported by the 1999 Cochrane systematic review of nine randomized, controlled trials, which revealed that delivery by vacuum extraction is more likely to fail when compared with delivery by forceps (OR: 1.7; 95% CI: 1.3–2.2), although both modes have an high overall success rate [15]. Regardless of the method, failure to achieve delivery of the fetus in a reasonable amount of time should be an indication for abandonment of the procedure.

In 2001, Murphy et al. conducted a prospective cohort study of 393 women requiring operative vaginal delivery. These deliveries were classified as ‘difficult’ operative deliveries and were performed only in the operating room in which recourse to a cesarean section would be an immediate possibility. There was an increase in maternal morbidity in the 35% of these women who underwent cesarean section at full dilation, as well as more neonatal intensive care unit admissions [16]. These data highlight the risk:benefit ratio of a major surgical procedure, such as a cesarean section, and lend support to deliver vaginally if possible.

Maternal morbidity with operative vaginal delivery: vacuum versus forceps

Maternal morbidity has long been thought to be greater when forceps are used rather than vacuum extraction. A 2004 retrospective chart review of 508 operative vaginal deliveries examined immediate fetal and maternal effects after both vacuum and forceps deliveries. This study found an increased risk of episiotomy (90.5 vs 81.8%; p = 0.01) and combined third- and fourth-degree perineal lacerations (44.4 vs 27.9%; p < 0.001) in the forceps groups compared with the vacuum group, although there was no significant difference in the number of third-degree lacerations between the two groups. This same study also demonstrated an increase in the number of periurethral lacerations in the vacuum group (4.2 vs 0.5%; p = 0.026) [17]. Vacuum extraction has also been associated with a decreased amount of blood loss at delivery and lower usage of regional anesthesia compared with forceps. A 1999 Cochrane systematic review comparing vacuum and forceps deliveries concluded that delivery by vacuum extraction is less likely to cause serious maternal morbidity (Figure 1), including less significant perineal and vaginal trauma (OR: 0.4; 95% CI: 0.3–0.5). Mothers reported less pain at the time of delivery and at 24 h after delivery with vacuum extraction compared with forceps. Although mothers appeared to be happier regarding their own morbidity following a vacuum delivery, they did tend to express more concern regarding the well-being of their neonate, than those who delivered by forceps (OR: 2.2; 95% CI: 1.2–3.9) [15].

Figure 1.

Vacuum versus forceps: a comparison of significant maternal injury.

Recent studies have also explored subsequent pregnancy outcomes and mode of delivery in women who have undergone a previous operative vaginal delivery. In 2003, Murphy et al. published a follow-up study on the previously mentioned cohort of 393 women requiring operative vaginal delivery. Of the cohort, 53% desired future pregnancy while 22% remained uncertain. Women who had an instrumental delivery were likely to prefer a future vaginal delivery, although that preference seemed to decrease over time. (79% at hospital discharge vs 68% at 1 year). There was no significant association between preference for vaginal delivery and history of neonatal trauma, obstetrical hemorrhage or urinary incontinence [18]. A follow-up of this same cohort at 3 years was also performed evaluating reproductive outcome and mode of delivery in subsequent pregnancies. Women were less likely to report difficulty conceiving and were more likely to have achieved a future pregnancy after an instrumental vaginal delivery than after a cesarean section. Women were also more likely to achieve a vaginal delivery after a previous instrumental delivery (OR: 9.50; 95% CI: 3.48-25.97), although 94% of those women desiring vaginal birth after cesarean section also achieved a subsequent vaginal delivery. From these data, it appears that previous instrumental delivery does not significantly decrease the desire or ability to achieve subsequent vaginal delivery [19].

Neonatal morbidity with operative vaginal delivery: vacuum versus forceps

While maternal morbidity appears to be less when vacuum extraction is used as the instrument of choice for operative vaginal delivery, there are concerns regarding neonatal morbidity. Neonates who are delivered by forceps do tend to be at an increased risk for minor facial abrasions and facial nerve palsies, whereas neonates delivered by vacuum extraction tend to have more caput and molding. In 1987, Broekhuizen et al. performed a retrospective cohort study analyzing both the success rates and morbidities of vacuum versus forceps deliveries. Findings from this study revealed that there was a significantly higher proportion of operative deliveries occurring from a occiput posterior or transverse position in the vacuum group than the forceps group (81.2 vs 27%), as well as a significantly higher proportion of deliveries occurring from +1 station or higher in the vacuum versus forceps group (59.8 vs 9%). Results of this study also demonstrated the potential for autorotation to a more favorable fetal position (58%) in the vacuum group, compared with the necessary active rotation that occurs with rotational forceps [20]. An advantage to vacuum delivery from these more unfavorable preapplication positions is decreased maternal trauma by less encroachment of the instrument on the genital tract and no active rotational force needing to be applied. One concern of this study is the higher incidence of shoulder dystocia in the vacuum group versus the forceps group (p < 0.01). A possible explanation would be more mid-pelvic deliveries with cephalopelvic disproportion in the vacuum group as a result of the above mentioned data. These findings reiterate the necessity of evaluating maternal pelvimetry, estimated fetal weight and the degree of fetal head molding prior to attempting an operative vaginal delivery. By doing so, mid-pelvic deliveries of large-for-gestational-age neonates may be avoided, thereby decreasing the risk for shoulder dystocia.

Delivery by vacuum extraction has also been associated with an increased neonatal risk of retinal hemorrhage, jaundice, intraventricular hemorrhage, cephalohematoma and subgaleal bleed. Berkus et al. published compelling safety data for the silastic vacuum extractor in 1985. In this prospective cohort study, 84 vacuum extraction deliveries were compared with 84 forceps and normal spontaneous vaginal deliveries. There were no differences in 1- and 5-min Apgar scores, jaundice, mean neonatal intensive care unit stay, or incidence of retinal hemorrhage between the vacuum and forceps delivery groups. No cases of intraventricular or subgaleal hemorrhage were noted in either of the groups. There was a greater incidence of cephalohematomas in the vacuum group but, unlike classic cephalohematomas, these vacuum-induced cephalohematomas resolved within 1 to 2 weeks, and only three of 12 neonates required phototherapy [21].

In 1991, Williams et al. conducted a prospective trial comparing 99 women requiring assisted vaginal delivery randomized to either vacuum or forceps. There was no difference in the intracranial hemorrhage rate, Apgar scores or cord gas values. There was an increase in facial trauma in the forceps group, although this mostly manifested as a transient facial nerve palsy secondary to placement of the blades on the facial nerve during delivery. Neonatal serum bilirubin levels were not different between both groups and none of the neonates required phototherapy. There was an increased rate of retinal hemorrhage in the vacuum-assisted group, although the clinical significance of this finding remains unclear [22]. A follow-up study by Williams et al. in 1993 evaluated other obstetrical causes of neonatal retinal hemorrhage and found that 25% of neonates delivered spontaneously had findings consistent with retinal hemorrhage compared with 38% of assisted-delivery infants (p < 0.03). Among the entire population, lower birth weight was significantly associated with moderate-to-severe retinal hemorrhage (p < 0.0008), with the strongest relationship among vacuum-assisted deliveries (p < 0.004). Of note, there was also a statistically significant relationship among spontaneous and forceps-assisted vaginal deliveries (p < 0.02) [23]. This study proposes that other factors, such as fetal acidosis and low birth weight, pose an increased risk for retinal hemorrhage and that these factors may be more commonly seen in fetuses requiring assisted vaginal delivery.

As addressed earlier, neither the ACOG or the RCOG have a consensus on the maximum total duration of a vacuum extraction procedure. A prospective observational study performed by Teng and Syre in 1997 examined 134 vacuum-assisted vaginal deliveries and identified variables that may increase the risk of neonatal scalp injury. Of the neonates, 21% experienced scalp trauma, only one case of which was diagnosed as a subgaleal hemorrhage. Factors associated with an increased risk of neonatal scalp trauma included vacuum procedures lasting more than 10 min and second stages of labor exceeding 120 min in duration. The hypothesis for this finding is that longer second stages and longer vacuum procedures allow more time for a ring of extrinsic pressure (either from the dilating cervix or from a vacuum cup) to allow for interstitial fluid to accumulate to form the caput. This may leave the fetal scalp tissue more vulnerable to abrasions, lacerations and cephalohematoma formation [24].

One of the landmark articles in the literature on operative vaginal delivery stems from a retrospective study conducted in 1999 by Towner et al. examining a California database of 583,340 nulliparous patients, a third of which underwent an operative vaginal delivery by either forceps or vacuum extraction. Neonatal outcomes were reviewed in each case. Prior to this study, operative vaginal deliveries had been compared solely to normal spontaneous vaginal deliveries. This analysis compared not only operative deliveries with spontaneous vaginal deliveries but also compared operative deliveries with cesarean sections performed during labor, which may actually be the most suitable comparison group. Results from this study revealed that rates of intracranial hemorrhage were overall low for all modes of delivery but higher with vacuum, forceps and cesarean section performed during labor than with a normal spontaneous vaginal delivery. There was no difference in neonatal safety comparing operative vaginal delivery versus cesarean section during labor. Rates of intracranial hemorrhage were also found to be similar in normal spontaneous vaginal deliveries and cesarean sections performed with no labor [25].

Towner's study also revealed striking data that there is an incremental increase of intracranial hemorrhage if more than one method of delivery is used (i.e., vacuum followed by forceps or failed operative vaginal delivery followed by cesarean section). Most primary cesarean sections are performed for disorders of labor arrest whereas most operative deliveries are performed for prolonged second-stage labors. It is possible that the position of the fetal head in the maternal pelvis during these protracted labors may be an individual risk factor for neonatal intracranial injury. In summary, this study raised the possibility that the neonatal morbidity of operative vaginal delivery, including cesarean section during labor, could be linked with the abnormal/dysfunctional labor process itself rather than the operative vaginal intervention. Therefore, vacuum extraction and forceps deliveries may be associated with an irreducible component of neonatal morbidity possibly attributed to a long, dysfunctional labor rather than the instrumentation itself, as previously hypothesized. This study also emphasizes that there is an increased risk of intracranial hemorrhage with the sequential use of two instruments. Intracranial hemorrhage in infants delivered by vacuum followed by forceps occurred at a rate 7.4-times (95% CI: 3.9–14.0) higher than spontaneous vaginal delivery and 3.4-times (95% CI: 1.7–6.6) higher than delivery by vacuum extraction alone [25]. Sequential use of instruments to achieve a vaginal delivery should be avoided as it poses an increased risk of fetal injury and may actually indicate cephalopelvic disproportion [7].

In an editorial response to this article, Dr Thomas Benedetti of the University of Washington School of Medicine, USA, concludes that if the chances of a successful operative vaginal delivery are low it should probably not be attempted. According to Towner's data, immediate resort to a cesarean section would pose the same level of risk to the fetus as an operative vaginal delivery, and repeated attempts at operative vaginal delivery, as well as failed vaginal delivery converted to cesarean section, would incrementally increase the risk of neonatal morbidity [26].

FDA issues warning on vacuum-assisted delivery devices

In 1998, the US FDA issued a warning on the need for caution when using vacuum-assisted delivery devices. This warning was based on reports of 12 deaths and nine serious injuries among newborn babies delivered by vacuum extraction. The warning goes on to describe both subgaleal hematoma and intracranial hemorrhage as two major life-threatening complications associated with vacuum-assisted delivery. In this report, the FDA issues four recommendations for the use of the vacuum device [27]:

Use only when a specific obstetric indication is present;

Apply steady traction in the line of the birth canal. Avoid rocking movements or applying torque to the device;

Alert the pediatricians who will be responsible for the neonate's care;

Report reactions associated with the use of the vacuum device to the FDA.

In September of that same year, the ACOG released a committee opinion in response to the FDA's recent Public Health Advisory. The two main concerns cited by ACOG were that first, the FDA has based its concerns on an extraordinarily low risk of adverse event and, second, given the decline in forceps use, any decrease in the use of vacuum-assisted delivery devices resulting from this advisory is likely to result in a higher cesarean delivery rate or increased use of forceps by practitioners with inadequate training. The conclusion by ACOG was that they strongly recommend the continued use of vacuum-assisted delivery devices in appropriate clinical settings by operators appropriately trained in the technique, indications and contraindications of their use [28].

Long-term neonatal outcomes after operative vaginal delivery

While concern exists over the neonatal safety of operative vaginal delivery, very few long-term studies are available. In 1991, Seidman et al. published a cohort study evaluating the long-term outcome of neonates delivered by forceps or vacuum extraction. A total of 52,282 infants born in Jerusalem between 1964 and 1972 were subjected to an intelligence test and physical examination at 17 years of age. After controlling for confounding factors, such as socioeconomic class and ethnic background, there were no significant differences in cognitive skills among those delivered spontaneously or by vacuum or forceps assistance [29]. Most recently, in 2007, a prospective cohort study by Bahl et al. was published in the American Journal of Obstetrics and Gynecology examining the neurodevelopmental outcomes in children at the age of 5 years born by either instrumental vaginal delivery or cesarean section in the second stage of labor. Outcomes were similar between the two groups and demonstrated only a very low risk of neurodevelopmental abnormality at 5 years of age. Of note, outcomes were also similar for children born by immediate cesarean section in the second stage of labor or by cesarean section after failed operative vaginal delivery [30]. While current data are limited, parents can be reassured that, at this point, there appears to be little risk of neurodevelopmental deficits in children born by operative vaginal delivery.

Manual rotation to assist vaginal delivery

Occiput posterior and occiput transverse positions account for approximately 13 and 12% of fetal positions in labor, respectively [15]. It has been postulated that these fetal positions are risk factors for cesarean section, instrumental delivery, longer second stages of labor and increased amounts of third- and fourth-degree perineal lacerations. The concept of manual rotation of the fetal head to a more favorable position for delivery was first described by Tarnier and Chantreuil in 1982 [31]. Their technique is performed after cervical dilation has reached at least 7 cm. During uterine relaxation, the operator places either two fingers or, preferably, the entire hand behind the fetal ear. During a contraction, the patient is instructed to push while the pressure of the hand is used to rotate the anterior fetal head. The fetal heart rate should be continuously monitored during this procedure. If the first attempt at rotation fails, a second attempt can be made as long as there are no abnormalities in the fetal heart tracing. Relative indications for this procedure have been described, but are not limited to [32]:

Prophylaxis to reduce the length of labor and avoid perineal consequences of an occiput posterior delivery

Acceleration of the end of the second stage of labor for fetal heart tracing abnormalities

Nonengagement of the fetal head

Failure to progress in labor

While this appears to be a potentially successful adjunct to vaginal delivery, there are relatively sparse data on the subject. In 2006, Shaffer et al. conducted a restrospective cohort study to analyze risk factors for a successful manual rotation. A total of 742 patients were included in the study, of which 74% delivered vaginally in the occiput anterior position after a successful manual rotation. Results of this study revealed that nulliparity and maternal age greater than 35 years were independent risk factors for a failed manual rotation. This study also analyzed risk factors for cesarean section after manual rotation and found that the aforementioned risk factors, as well as induction of labor and epidural anesthesia, placed a patient at an increased risk for cesarean section after manual rotation. Of note, induction of labor and epidural anesthesia were not associated with failed manual rotation. Only 2% of patients in this study who underwent a successful rotation went on to deliver via cesarean section compared with 34% who underwent a failed rotation [33]. These findings were most currently supported by a 2007 retrospective case–control study that again analyzed risk factors manual rotation success in 796 women and found similar results. In addition, this recent study demonstrated a trend towards increased rate of failure of manual rotation when performed before complete cervical dilation and for the indication of failure to progress in labor. This study also supported the increased risk of cesarean section after failed manual rotation compared with successful rotation (58.8 vs 3.8%) [32]. Together, these data suggest that manual rotation can be an effective technique for reducing the cesarean section rate in patients with a fetus in either occiput posterior or occiput transverse positions.

Some controversy surrounds the relative indication of manual rotation as prophylaxis to reduce the duration of labor. As with any procedure, manual rotation is not without risk. Although rare, the obstetrical risks of this procedure include severe fetal heart-rate decelerations, cord prolapse and cervical laceration. The question has been posed as to whether prophylaxis is justified in light of these possible adverse outcomes. Le Ray et al. reported only one fetal heart-rate abnormality requiring cesarean delivery out of 64 prophylactic rotations [32]. In 1995, Haddad et al. quoted a 97% success rate for rotations performed for prophylaxis compared with a 28% success rate for rotations performed for lack of progress [34]. Given these numbers, it appears that manual rotation does indeed have a role in current obstetrics and may be an adjunct to successful vaginal delivery without increasing the rate of cesarean delivery.

Conclusion

Both forceps and vacuum extractors are acceptable and safe instruments for operative vaginal delivery. While candidates should be selected on an individualized basis and counseled accordingly, the skill of the operator should also influence the decision to attempt an operative delivery as well as the choice of instrument. Concerns regarding serious neonatal morbidity associated with vacuum extraction have not been substantiated by multiple well-designed studies. Additionally, long-term data, although limited, do not suggest any increased risk of neurodevelopmental delay in children delivered by either vacuum or forceps. While maternal morbidity may be slightly higher with forceps delivery, it is overall low in comparison with the morbidity that may be associated with delivery by cesarean section. In an era in which cesarean section rates are climbing, practitioners in obstetrics are encouraged to consider all of the available delivery modes and to tailor them accordingly for each patient in order to ensure the most efficacious and safest delivery experience.

Future perspective

As the number of clinicians skilled in operative vaginal delivery declines, residents in obstetrics are completing their training without feeling comfortable in performing operative vaginal deliveries, especially forceps. According to the Accreditation Council for Graduate Medical Education residency case logs, the mean number of forceps and vacuum deliveries for all residents in 2006 was 13 and 22, respectively [101]. Residency programs are no longer requiring their trainees to demonstrate competency in both forceps and vacuum deliveries, rather an umbrella competency in ‘operative vaginal delivery’ is being substituted. Again, this is primarily driven by the decreasing number of skilled clinicians able to teach residents and possibly compounded by misconceived notions regarding the safety of the instruments. In 2007, Powell et al. published the results of a national survey evaluating the experience of US chief residents with forceps and vacuum deliveries. Almost all of the respondents felt competent to perform vacuum deliveries, whereas approximately only half felt competent to perform forceps deliveries. Those with a low level of self-perceived competency reported that they would probably not use forceps in their practice [35]. It is imperative that residency training programs continue to strive to teach these skills so that operative vaginal delivery can be performed in a safe and efficacious manner as an alternative to cesarean section for carefully selected patients. As practitioners in obstetrics, it is our goal to ensure that operative vaginal delivery does not become a dying art and continues to remain a valuable modality in modern obstetrics.

Executive summary

Prior to attempting an operative vaginal delivery, the fetal position, presentation, lie and any degree of asynclitism should be assessed as well as the adequacy of the maternal pelvis.

If either progressive descent of the fetal head does not occur with each pull or delivery is not imminent following three pulls of a correctly applied instrument by an experienced operator, the procedure should be abandoned and delivery via cesarean section should occur.

Vacuum-assisted delivery should be avoided in cases of an unengaged fetal head, nonvertex presentation and in fetuses with a bone demineralization or bleeding disorder. In cases of prematurity less than 34 weeks or suspected macrosomia, the risks and benefits should be carefully considered prior to attempting a vacuum-assisted delivery.

Both vacuum and forceps have an overall high success rate, although when compared with forceps delivery, a vacuum delivery is more likely to fail.

Delivery by vacuum extraction is less likely to cause serious maternal morbidity, including less significant perineal and vaginal trauma, compared with delivery by forceps.

Neonatal morbidity associated with operative delivery, including cesarean section during labor, may be a function of an abnormal labor process itself rather than the operative vaginal intervention.

Sequential use of instruments (i.e., failed vacuum attempt followed by forceps) is associated with an incremental increase in neonatal intracranial hemorrhage and should therefore be avoided.

Manual rotation of the fetal head can be an effective technique for reducing the cesarean section rate in patients with a fetus in either occiput posterior or occiput transverse positions.

Footnotes

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

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Operative Vaginal Delivery: Current Trends in Obstetrics

Abstract

Keywords

Indications & prerequisites for operative vaginal delivery

Operative vaginal delivery techniques

Vacuum extraction

Forceps delivery

Efficacy of operative vaginal delivery

Maternal morbidity with operative vaginal delivery: vacuum versus forceps

Neonatal morbidity with operative vaginal delivery: vacuum versus forceps

FDA issues warning on vacuum-assisted delivery devices

Long-term neonatal outcomes after operative vaginal delivery

Manual rotation to assist vaginal delivery

Conclusion

Future perspective

Footnotes

References