Pearls on Forceps Delivery

Although the number of forceps deliveries has declined considerably in the United States in recent decades, forceps remain an important part of the obstetric armamentarium. An experienced practitioner offers insights and caveats plus advice on cutting legal risks.

Dr. Bofill is associate professor, department of OBG, division of maternal-fetal medicine, at the University of Mississippi Medical Center in Jackson, Miss.

Ensure a proper indication. Forceps delivery should be considered when a nulliparous gravida experiences a prolonged second stage of labor, when there is a nonreassuring fetal heart rate or any indication of nonreassuring fetal status, or when the mother is unable or unwilling to push during the active phase of delivery. Forceps also may be appropriate when the mother has a cardiac or neurologic condition that makes it inadvisable for her to perform the Valsalva maneuver.

When used judiciously and skillfully, forceps are a safe instrument for operative vaginal delivery.

Incomplete dilatation of the cervix is an absolute contraindication to forceps delivery, as is any obstruction in the birth pathway (e.g., vaginal tumor). Other contraindications include a grossly misshapen pelvis, cephalopelvic disproportion, and an inability to achieve proper application of forceps. Nor are forceps advised when the leading edge of the infant’s skull is at a high station or if prenatal imaging or other assessment suggests the fetus is macrosomic. (When the fetal weight is borderline, however, I generally opt for forceps unless the mother is diabetic.)

Guidelines for HIV-positive women. The National Institutes of Health (NIH) suggest cesarean delivery when an HIV-positive woman has a viral load exceeding 1,000 copies of HIV RNA per milliliter of blood. But forceps delivery is an option when the viral load is less than that amount. Since it is important to avoid creating abrasions through which the virus can be transmitted at the time of delivery, I generally opt for forceps rather than the vacuum extractor.

Take the proper preoperative steps. First, rule out cephalopelvic disproportion. In this regard, the Mueller-Hillis maneuver is useful. Using it, the physician places 2 fingers on the fetal skull during the second stage of labor. The other hand is placed on the fundus, and gentle pressure is applied. If the baby descends in the pelvis, forceps then are applied with gentle traction to confirm descent. If the baby does not move at all during the maneuver, cephalopelvic disproportion is likely.

Next, assess fetal head position and ensure full dilation, rupture of membranes, and adequate anesthesia. The patient should be placed in the dorsal lithotomy position, with as little pressure applied to her legs as possible, and should have an empty bladder. (If the bladder is distended, she should be catheterized. In addition, I closely monitor bladder output in preeclamptic patients.) The fetal head must be engaged, and the position and station of the presenting part must be known both before and after application of forceps. Medical staff with expertise in neonatal resuscitation should be on hand, and immediate access to cesarean section should be available unless the delivery is an outlet procedure.

Pay attention to anesthesia. Make sure that the patient receives or has available adequate anesthesia. When forceps delivery is an outlet procedure, options include a regional anesthetic and a pudendal block. Although I prefer epidurals, they have been associated with a prolonged second stage of labor. Thus, institutions that rely heavily on epidurals generally have higher operative vaginal delivery rates. While women usually are accepting of forceps delivery when it is indicated by unforeseen complications of labor, they may be less tolerant when the indication is simply weakness and numbness caused by the anesthetic. For this reason, it is important to counsel patients about all their anesthetic options prior to labor and delivery, and to discuss the possibility that operative delivery may be necessary.

Choose your forceps. Since I prefer fenestrated blades, I generally rely on classic forceps, primarily the Simpson or Elliot forceps. On occasion, I will teach the use of the nonfenestrated Tucker McLean forceps. In rare instances, specialized forceps may be necessary, such as the Kielland forceps, useful when rotation of the fetal head is required.

When rotation is necessary. Rotations of less than 45 degrees rarely increase the level of risk in forceps deliveries.⁷ When the rotation exceeds 45 degrees, however, the data are unclear. I believe there is a greater chance of laceration to the mother, injury to the baby, and acidemia in the infant any time rotation is required.

In selected cases, I perform rotations using forceps. At present, however, most are more easily accomplished using the vacuum. Special cups now are available that can be applied in difficult positions of the fetal head—e.g., occiput posterior or occiput transverse—with a significant amount of success.

Rotations also can be done manually. In fact, I like to teach residents this skill. I start by asking them to compare their hands with mine, pointing out that we all have different “tools.” What works well using my hands may not be as successful for them. Although I demonstrate how I perform a manual rotation, I let each resident know the necessity of developing his or her own technique. Typically, I will identify the posterior portion of the fetal ear. When the mother pushes, I rotate the fetal head by placing my index or middle finger behind the fetal ear and applying pressure so that the fetal head will rotate toward the occiput anterior position. I’ve done this hundreds of times and have yet to see a single fetal injury. Some physicians are able to place rotational pressure on the sutures, while others are able to place their entire hand in the vagina and turn the fetal head with their fingers and thumb.

Proper placement is key. When placing the left branch of the Simpson forceps, I put the fingers of my right hand between the fetal head and the maternal vaginal sidewall, with my thumb on the heel of the forceps blade (Figure 1). My left hand exerts no pressure on the forceps, and I place only 3 fingers on the handle, making sure to avoid placing my palm against it. When introducing the right branch of forceps into the vagina, my right hand simply guides the handle, while my left hand protects the vaginal sidewall (Figure 2).

Once forceps are placed and loosely articulated, I perform a series of checks to ensure appropriate application. These checks include confirming that the sagittal suture is the same distance from each of the forceps blades and is perpendicular to the shanks. In addition, the posterior fontanelle should be 1 cm above the plane of the shanks, and no more than a fingertip should be able to fit between the fenestrated blade and the fetal cheek.

Excessive pressure is the culprit in most complications involving forceps. Thus, I emphasize the importance of guiding the handle using fingers only—rather than the palm. Another way to minimize the amount of pressure exerted is to sit on a stool while using forceps.

Skip the episiotomy. At my institution, as in many others across the country, we have made a conscious decision to perform fewer episiotomies. Since 1995, the number of episiotomies has declined dramatically. In fact, most of our forceps deliveries are accomplished without an incision. Only if the perineum looks as though it is about to rupture do I stop and perform one.

The Saxtorph-Pajot maneuver. With this maneuver, I am able to follow the curve of the pelvis—sometimes called the “curve of Carus.” It allows me to approximate the correct vector to guide the baby through the pelvic outlet. When the baby is occiput anterior, I use the maneuver in all forceps deliveries to guide the fetal occiput underneath the maternal symphysis pubis. The physician’s right hand pulls outward while the left hand presses downward (Figure 3).

When learning this maneuver, residents often ask, “How do I know when to stop applying pressure?” I teach them to insert a finger of their non-dominant hand between the fetal occiput and the symphysis pubis. That is the easiest way to determine whether the fetal occiput has cleared the underside of the symphysis. If it has, it is time to gently raise the handle of forceps, which extends the fetal head as in spontaneous delivery.

Complete delivery. As the handles of forceps are raised, I support the perineum (Figure 4). If the fetal chin can be easily palpated, forceps may be disarticulated and the delivery completed using the modified Ritgen maneuver. For this maneuver, upward pressure is applied to the baby’s chin, inferior to the mother’s anus, to help the head emerge in the desired direction. The maneuver also helps prevent excessive stretching of the perineum.

If the chin is not easily palpable, the fetal head should be extended using forceps, which are removed only after the head is entirely delivered from the vagina.

Be alert to possible complications. Despite their safety in the hands of experienced obstetricians, forceps are associated with vaginal and cervical lacerations, postpartum hemorrhage, and maternal infection. Potential fetal complications include cephalohematoma, facial nerve palsy, and depressed skull fracture. While forceps deliveries also have been associated with brain hemorrhage and significant acidemia, these complications tend to occur in severely premature, low-birth-weight, and other high-risk infants. Brain hemorrhage and significant acidemia also occur more often when the delivery involves the use of high or mid-cavity rotational forceps—i.e., when forceps are applied when the infant is still relatively high in the pelvis. However, high forceps deliveries are now “banned,” and deliveries from the midpelvis are very infrequent. Today, most forceps births are outlet deliveries.

Properly manage periurethral lacerations. When the mother sustains periurethral lacerations, I insert a Foley catheter after delivery and leave it in place overnight to facilitate proper drainage and healing. Otherwise, the postoperative management of forceps patients is the same as for other types of vaginal delivery.

Keep teaching the skill. When used judiciously and skillfully, forceps are a safe instrument for operative vaginal delivery. In my institution, residency training and practice in the proper use of forceps is considered an important part of graduate medical education. While residents are taught how to use the vacuum extractor, approximately 80% of operative vaginal deliveries are performed via forceps. I even use that statistic to entice future residents, saying, “If you believe that learning the use of forceps is important, you should strongly consider our program.” I also point out that a “vacuum-only” strategy is not viable, since vacuum extraction cannot be used safely at gestational ages less than 34 weeks. Moreover, in many different venues—particularly in rural areas, where the operative team must be assembled—a simple forceps delivery can be accomplished much more quickly than a cesarean section.

Editor’s note: The criteria for the different types of forceps delivery are listed in ACOG Practice Bulletin #17: Operative Vaginal Delivery.

The author reports no financial relationship with any companies whose products are mentioned in this article.

OBG Management ©2002 Quadrant HealthCom Inc.