Forceps Delivery Procedures Technique

Updated: Apr 11, 2017
  • Author: Michael G Ross, MD, MPH; Chief Editor: Nicole W Karjane, MD  more...
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Technique

Approach Considerations

The most crucial point of forceps delivery is knowledge of the presentation and position of the fetus.

In the usual forceps application, the blades of the forceps are inserted so as to lie over the fetal cheeks, with the 2 blades placed symmetrically. 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 actual fetal position. Pelvic application is never to be used as a substitute for knowledge of the fetal position; inappropriate pelvic application may cause significant harm.

Once again, it is crucial to note that the success of forceps delivery is dependent on the skill and training of the operator. 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. Simulator experiences may be available to assist the student in achieving the necessary level of skill, [5, 6, 7, 8] and there is evidence suggesting that simulator use improves performance of the procedure. [9, 10]

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Forceps Delivery

Application technique for occiput anterior position

After proper anesthesia is achieved and an empty bladder ensured, the fetal position is checked again. [1] The presence of the sagittal suture in the anteroposterior diameter of the pelvic outlet is confirmed.

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 (see the images below). 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 left handle is held in the left hand (Simpson The left handle is held in the left hand (Simpson forceps).
The left blade is introduced into the left side of The left blade is introduced into the left side of the pelvis.

Next, the right blade is introduced into the right side of the pelvis in the same fashion (see the image below).

The left blade is in place and the right blade is The left blade is in place and the right blade is introduced by the right hand.

At all times, efforts should be made to avoid 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 primarily guide the blades and should apply minimal pressure on the fetal head.

Forceps application 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 with minimal pressure.

Generally, when the occiput is not directly anterior, the blade should be applied first to the lower half of the fetal head so as to avoid turning the head to a transverse position with the first blade application. Alternatively, it may be preferable to apply the blade first to the upper half of the head because of the reduced space between the head and the pubic bone. 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 occipitomeatal diameter. With the ends of the blades lying over the posterior cheeks the blades should lie symmetrically on either side of the head (see the image below).

An illustration of a forceps delivery technique. An illustration of a forceps delivery technique.

The sagittal suture of the fetal head is in the midline, and the blades are relatively equidistant from the sagittal suture. 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, depending on fetal station (see the image below).

The forceps have been locked. The inset shows a le The forceps have been locked. The inset shows a left occipitoanterior fetal position.

The appropriateness of forceps application should be confirmed before traction is applied.

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, though it is uncertain whether this measure is truly beneficial. In an emergency, it may be necessary to apply traction continuously until the fetal head delivers.

Once proper forceps application has been confirmed, traction is initiated parallel to the plane of horizon (depending on fetal station; see the first image below) and is then elevated to an almost vertical direction as the fetal head extends (see the second image below).

An illustration of horizontal traction with the op An illustration of horizontal traction with the operator seated.
An illustration of upward traction. An illustration of upward traction.

Traction should be limited to the minimum necessary to accomplish safe fetal head descent. Although biomechanical studies have suggested safe limits of 45 lb for primiparas and 30 lb for multiparas, no firm consensus on the amount of traction force has been reached. 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, in general, 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 (see the image below). With forceps delivery, less opportunity exists for the maternal tissues to stretch, and episiotomy may allow a more rapid delivery. The use of episiotomy to prevent short-term and long-term maternal injury is controversial. [11]

A median or mediolateral episiotomy may be perform A median or mediolateral episiotomy may be performed at this point. A left mediolateral episiotomy is shown here.

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.

An illustration of disarticulation of the branches An illustration of disarticulation of the branches of the forceps; beginning modified Ritgen maneuver.
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Complications

Maternal

Immediate maternal complications of forceps delivery include lacerations of the vagina and perineum. In the United States, the reported risk of third-degree and fourth-degree perineal tears after forceps delivery is 3-10% [12] ; this represents a substantial increase over the risk of such tears after spontaneous vaginal delivery. The risk of these tears appears to be rising, although the reasons for this rise are uncertain. [13, 14] The risk of perineal lacerations may be reduced by performing an episiotomy [15, 16] ; mediolateral episiotomy, [17, 18] but not median episiotomy, [19, 20] has been shown to be effective.

Vaginal lacerations are also associated with forceps deliveries; however, the level of risk is unclear, with reported incidences of vaginal laceration after forceps delivery ranging from 2% to 50%. [12] Finally, the risk of hemorrhage may be increased in forceps delivery, [12] though it is not known whether this effect is due more to confounding factors such as prolonged second stage and uterine atony.

Forceps delivery has been associated with an increased risk (7-13%) of incontinence of flatus and feces in the first year after delivery. [21, 22] Urinary incontinence has been reported in up to 24% of women within 6 months of a forceps delivery, [21] and the relative risk for urinary incontinence is reported to be 1.5 for forceps delivery as compared with spontaneous vaginal delivery. [23]

Six to 11 years after delivery, vaginal delivery is associated with a decrease in pelvic muscle strength as compared with cesarean delivery, and this decrease is more marked after forceps delivery. [24] Perhaps owing to this decrease in muscle strength, forceps delivery is associated with an increase in fecal incontinence [25] and in a general index of pelvic floor disorders (incontinence of urine and feces and pelvic organ prolapse) [26] 5-12 years after forceps delivery. A study by Volløyhaug et al that compared forceps to vacuum delivery 16-24 years after their first delivery found that forceps delivery was associated with more pelvic organ prolapse, levator avulsion and larger hiatal areas than were vacuum and normal vaginal deliveries. [27]  Despite these potential risks, it is unclear whether the outcomes are directly a result of forceps use or whether they are a result of the clinical labor conditions for which forceps were utilized.

Neonatal

When forceps delivery is appropriately employed, newborns delivered in this way have an acid-base status similar to that of infants delivered by cesarean section at full cervical dilatation. [28] No differences have been found in the rates of neonatal demise or neonatal encephalopathy after operative vaginal delivery. [29] Forceps deliveries may be associated with a variety of traumatic fetal injuries. Minor forceps marks and facial bruising are common, occurring in about 15% of patients. Facial nerve injury is relatively uncommon (0.5%) but is strongly associated with forceps delivery. [11]

Brachial plexus injuries are strongly associated with forceps deliveries. [30] They are typically a consequence of dystocia after head delivery rather than a direct result of forceps use. Permanent brachial plexus injuries are rare but are more highly associated with forceps deliveries, and the risk for permanent injury in a larger (>4000 g) fetus delivered with a forceps may approach 1/1000. [31]

Skull fracture is a rare complication of forceps delivery. [32] It may be a consequence of head compression by the bony pelvis rather than force applied by the forceps blade. Overall, the risk for serious morbidity with forceps delivery is 1.5% (compared to 0.5% for spontaneous vaginal delivery), [2] and the risk of fetal or neonatal death is 0.05% (compared with 0.02%). [2]

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