Forceps Delivery Treatment & Management

Reviewing the indications for operative vaginal delivery and confirming the presence of all the prerequisites for forceps application are crucial steps. In particular, the presentation, position, and station of the presenting part must be reconfirmed just before the procedure.

Maternal verbal consent should be obtained prior to the forceps attempt, although the procedure may need to be performed emergently or after the mother has been medicated. If a planned forceps delivery is to be performed (ie, for maternal medical indications), counseling and consent may be completed prior to the onset of active labor.

The type of forceps to be used depends on the specific indications and conditions. The most commonly used forceps are Simpson forceps, which are used to deliver a molded fetal head, as is commonly seen in nulliparous women. Also commonly used are Tucker-McLane forceps, which have a more rounded cephalic curve, more suitable for the unmolded fetal head commonly seen in multiparous women. Kjelland forceps are made for rotation of the fetal head and lack a pelvic curve. Many instruments are available with the Luikart modification (pseudo-fenestrated).

The decision of what type of anesthesia is used should be made before initiating the delivery. An adequate level of anesthesia should be in effect before forceps application. Although published reports suggest that using only local infiltration anesthesia to the perineal body is enough, the authors believe that this type of anesthesia may be less than adequate. Very few women can tolerate forceps application without, at a minimum, pudendal block anesthesia. Attempts to "force the issue" with inadequate anesthesia may be intolerable to the mother. Pudendal block anesthesia may be augmented with intravenous sedation.

Adequate anesthesia is also achievable with regional or general anesthesia. Regional anesthesia is often used; general anesthesia is usually reserved for very unusual emergency situations. With the former, the patient should be prepared and draped after the anesthesia has been delivered via epidural or spinal injection. With the latter, the surgeon should be ready, with the patient properly draped, before administration of general anesthesia.

The bladder should be emptied in preparation for forceps operative deliveries, regardless of the type of anesthesia used.

Some authors have advocated the routine use of prophylactic antibiotics prior to operative vaginal delivery. This recommendation is based on a study that found a decreased incidence of perineal wound infections in treated patients. ^[5]  The patients in the study had a high incidence of mediolateral episiotomies, which are not commonly used in the United States. The American College of Obstetricians and Gynecologists (ACOG) recommends that prophylactic antibiotics be considered for patients with a planned episiotomy associated with an operative vaginal delivery. ^[2]

Application of the forceps

The most crucial point of forceps delivery is knowledge of the presentation position of the fetus. The term pelvic application is used when the left blade is applied on the left side of the pelvis and the right blade is applied on the right side of the pelvis, regardless of the fetal position. Pelvic application is never to be used as a substitute for knowledge of the fetal position; inappropriate pelvic application may cause maternal harm.

Once again, emphasizing that forceps delivery is skill- and training-dependent is important. The operator must have a clear understanding of his or her own capabilities, as well as the safe limits of the procedure, and must not exceed either of these.

Application technique

After ensuring proper anesthesia and an empty bladder, the fetal position is again checked prior to introducing the instrument. The presence of the sagittal suture in the anteroposterior diameter of the pelvic outlet is confirmed, and the left forceps blade is introduced into the posterior half of the left side of the pelvis and is guided to the appropriate position along the fetal head.

The placement and guidance are performed by the operator's right hand in the maternal pelvis. The left blade is left in place to stand freely or is held in place without pressure by an assistant. The right blade is introduced into the right side of the pelvis in the same fashion.

At all times, attention should be given to avoiding the use of excessive force. At the beginning of the application, the blades should be held like a pencil, almost in a vertical position; as the blades are introduced into the vagina, they are brought to a horizontal position. Avoiding levering or forcing the blade with the nonvaginal hand is critical. The fingers in the vagina should only guide the blades and should not apply pressure on or displace the fetal head. The application of the forceps is generally not performed during a uterine contraction; however, properly placed blades may be left in place if a contraction ensues during placement.

After proper placement of the left blade, it should lie almost parallel to the floor. With insertion of the right blade, the forceps should lock without pressure.

When the occiput is not directly anterior, applying the blade to the lower half of the fetal head first to avoid turning the head to a transverse position with the first blade application is desirable. At times, this requires placement of the right blade first.

Appropriateness of application

In a proper cephalic application, the long axis of the blades corresponds to the occipitomental diameter, with the ends of the blades lying over the posterior cheeks (see image below); the blades should lie symmetrically on both sides of the head. The sagittal suture of the fetal head will be in the middle, and the blades will be equidistant from the sagittal and occipital sutures. At no time should any part of the forceps cover any midline structure. The forceps should lock easily with minimal force and stand parallel to the plane of the floor. The appropriateness of application should be confirmed before applying traction.

Traction with forceps and episiotomy

During an indicated forceps delivery, traction is applied during contractions. The instrument may be used to maintain the station of the fetal head between contractions. In an emergency, applying continuous traction may be necessary until the fetal head delivers.

After confirming proper forceps application, traction starts parallel to the plane of horizon and is then elevated to an almost vertical position as the fetal head extends, and the forceps are removed as the fetal head delivers through the perineum.

The amount of traction should be the least necessary to accomplish safe fetal head descent. In biomechanical studies, safe limits of 45 pounds in primiparas and 30 pounds in multiparas have been suggested, though there is no consensus on the amount of traction force. ^[6] The angle of traction is as important as the force applied in effecting delivery. Knowing when to stop and abandon the procedure is a matter of experience; however, assuming that everything has been done according to proper protocols, if no progress is observable in 3 traction attempts, abdominal delivery should be considered.

Episiotomy may be performed when the perineum is distended by the fetal head. There is some evidence that episiotomy use may protect the rectal sphincter, ^[7]  although in the United States routine episiotomy is not favored. ^[2]

With forceps delivery, less opportunity exists for the maternal tissues to stretch, and episiotomy may be performed to allow a more rapid delivery. The utility of episiotomy in preventing short- and long-term maternal injury is controversial. ^[8]

As the fetal head crowns, the forcep blades are disarticulated and removed (see the image below), and the remainder of the delivery proceeds as for a spontaneous vaginal delivery.

After a forceps delivery, thorough examination of both the mother and the newborn is advisable. Maternal cervical, vaginal, and perineal lacerations must be excluded. In addition, maternal vulvar edema may be significant. Most operators institute measures such as perineal ice to ameliorate this. Pain medication is also advisable. These patients are at increased risk for hemorrhage, and a postoperative hemogram should be obtained and the condition corrected as needed.

Before discharge, pelvic and rectal examinations may help confirm the integrity of pelvic organs and may exclude such entities as pelvic hematoma, rectal tears, and misplaced sutures. Diagnostic studies should be obtained as needed. Antibiotics can be considered for patients who experience third- or fourth-degree perineal lacerations. ^[2]

The newborn must be examined for lacerations, bruising, and other injuries. The pediatric service should be made aware of the circumstances of delivery.

In the absence of specific forceps-related complications, a follow-up postpartum examination within 4-6 weeks, according to the usual protocol for postpartum care, with a thorough pelvic examination, is usually sufficient.

Either mother or infant may experience complications related to a forceps-assisted delivery. Research into forceps delivery complications is hampered by a number of potential biases: Maternal and fetal complications have been reported to vary depending on skill and judgment of the operator; however, this is difficult or impossible to quantify. In addition, there is the problem of the comparison group; complication rates are often quoted in comparison to normal deliveries, but forceps deliveries are often performed in patients with complicated pregnancies or abnormal labors.

Early maternal complications include lacerations and bleeding. Even with appropriate use, forceps deliveries may be associated with an increased risk of perineal tears, ^[9] possibly due to the more rapid stretching of the tissues with delivery of the fetal head. One center was able to reduce the incidence of serious (third- or fourth-degree) perineal tears at operative vaginal delivery by a series of interventions. ^[10] The incidence of serious tears was reduced from 41% to 26% using a policy of increased use of vacuum delivery (from 16% to 29% of instrumental deliveries), use of mediolateral episiotomy, and changes in forceps technique. In addition to overt perineal tears, forceps deliveries have been associated with an increased incidence of tears of the levator ani, and this can be demonstrated by pelvic ultrasound. ^{[11, 12]}

Late maternal complications are largely related to damage to the pelvic support tissues; this damage may occur in the form of anatomic deficits, such as fistulae, or in defects in rectal sphincter function, due to both tears and nerve damage at the time of delivery. The finding of an increased risk of fecal incontinence after forceps delivery has been confirmed by numerous studies. ^[13] In one study, the rate of fecal incontinence was increased to 23% after an instrumental delivery (80% of these were forceps deliveries). ^[14]

As described above, the degree of increase is dependent on the comparison group, as the risk of incontinence after a normal spontaneous delivery was only 1.4%, whereas the use of an epidural anesthetic followed by a vaginal delivery was associated with a 6% risk. The same authors found that instrumental deliveries were associated with an increased risk of both damage to the rectal sphincter and with reduced pudendal nerve conduction velocity; not all patients with abnormal testing had symptoms. Whereas some authors have suggested that mediolateral episiotomy may reduce the risk of anal sphincter injury, ^[15]  others have demonstrated no benefit of routine episiotomy. ^[16]

Although urinary incontinence is common in women during the immediate postpartum period (4 months), forceps delivery is associated with an increased incidence. ^[17] The long-term consequence of forceps on urinary incontinence remains unknown. Despite the concern for potential forceps complications, forceps have a relatively low risk of adverse outcome when used by experienced operators. Even Kjelland rotational deliveries, which are now uncommonly performed, are successful in up to 95% of appropriately chosen cases with rates of maternal complications equivalent to vacuum delivery. ^[18]

Forceps deliveries are associated with an increased incidence of forceps marks and bruising of the fetal face, ^[9] occurring in 17% of infants delivered by forceps. ^[19] Most of these injuries are trivial, but forceps delivery may also be associated with fetal injuries leading to long-term disability; transient or permanent facial nerve injuries have been reported in up to 0.5% of forceps-assisted deliveries. The facial palsy is most often mild and resolves without therapy. ^[20]

More concerning, the incidence of intracranial bleeding is increased with forceps delivery, with odds ratios between 2 and 4 being reported. Skull fractures have been reported with forceps deliveries; one report documented a rate of 1 per 4500. ^[21] Shoulder dystocia has been reported in association with forceps delivery; however, many studies have not found this association. ^[22] In addition, cerebral palsy and subtly lower IQ (2.5 points) have been described in infants delivered by forceps; however, it is not apparent whether the association of shoulder dystocia and fetal central nervous system (CNS) injury is with the forceps delivery per se, or with prolonged and difficult labors.

Towner et al examined the risk of intracranial hemorrhage in 583,340 live-born singleton infants born to nulliparous women between 1992 and 1994 and weighing between 2500 g and 4000 g. One third of the infants were delivered by operative techniques. Although the rate of intracranial hemorrhage was higher among infants delivered by vacuum extraction or forceps, as compared to those delivered spontaneously, the rate was similar to that of cesarean delivery during labor. These results suggest that the common risk factor for intracranial hemorrhage is abnormal labor rather than operative delivery per se. ^[23]

Despite the potential complications, when used appropriately forceps deliveries are as safe as vacuum deliveries to the neonate. ^[24] A study found that the rate of overall neurologic injury (seizures, intraventricular hemorrhage, and subdural hematoma) was lower with forceps deliveries than with either vacuum delivery or cesarean delivery in labor. ^[25]

Finally, the risk of maternal and fetal complications is increased if a forceps delivery is attempted after a failed vacuum extraction. The risk of maternal vaginal laceration and hemorrhage was increased in one study, with the relative risk of a fourth-degree tear being 11 when compared with normal delivery. ^[26] One study found an odds ratio of 7 for CNS bleeding, and an odds ratio of 4 for neonatal seizures in infants delivered via a combined procedure, ^[23]  whereas another found an increase in the incidence of brachial plexus injuries and facial nerve injuries. ^[26]

At least some of this excess risk is related to the risk associated with a failed instrumental delivery, as the risk for neonatal morbidity has been reported to be the same for patients after a failed vacuum extraction regardless of whether the next option was forceps or cesarean delivery. ^[27] If one elects to use forceps following a trial of vacuum, pelvic capacity and the risk/benefit should be carefully assessed.

The use of forceps has been associated with long-term maternal and fetal morbidity. The remaining question is whether the association implies causality. In one study, the use of forceps electively was not associated with an increase in maternal or fetal morbidity in patients who were randomly assigned to delivery spontaneously or by forceps. ^[28] Unfortunately, this study contained only 50 patients and thus was underpowered to find the kind of serious morbidities described. This study also does not address the more frequent case, in which forceps delivery is used urgently as an alternative to cesarean delivery.

The future of forceps deliveries is in doubt. Information developed in the 1980s suggests that fetal outcome may be poor after at least some forceps deliveries. Other data suggest that long-term compromise of the maternal rectal sphincter is a common sequela of forceps delivery. In view of the discussions of the merits of cesarean delivery on demand for preservation of maternal pelvic musculature, the place of forceps deliveries in obstetrical practices has been questioned.

Given the current state of knowledge, it is the position of the American College of Obstetricians and Gynecologists that forceps delivery remains an acceptable and safe option for delivery. ^[2]  However, recent birth certificate data from the United States report a total forceps rate of 0.7%. ^[29] These data suggest that experience and skill with forceps delivery have become difficult to obtain, leading to concerns about the survival of the procedure.