Operative Vaginal (Forceps) Delivery for Fetal Indication Case File

Operative Vaginal (Forceps) Delivery for Fetal Indication Case File

Eugene C. Toy, MD, Edward Yeomans, MD, Linda Fonseca, MD, Joseph M. Ernest, MD

Case 30

A 23-year-old Caucasian woman, G1P0, at 33 weeks’ gestation is undergoing induction of labor for severe preeclampsia. She has a functioning epidural catheter in place and has been pushing for 20 minutes. The fetal heart rate (FHR) tracing has been normal (category I) throughout the labor but you are called to the bedside for a prolonged deceleration to 60 beats per minute (bpm) lasting 3 minutes. You perform a sterile vaginal examination that rules out a prolapsed umbilical cord, and confirms complete dilation of the cervix with the fetal head at +2 station. Now at 7 minutes the FHR remains in the 60s.

➤ What is the most likely diagnosis?

➤ What is your next step?

➤ What complications are associated with your method of management?

ANSWER TO CASE 30:

Operative Vaginal (Forceps) Delivery for Fetal Indication

Summary: A nulliparous woman with severe preeclampsia at 33 weeks’ gestation is being induced with oxytocin. She has reached the second stage of labor and now manifests a fetal indication for expeditious delivery.

➤ Most likely diagnosis: Prolonged deceleration of the FHR in the second stage of labor.

➤ Next step: Forceps-assisted delivery.

➤ Complications: Maternal complications include hemorrhage from genital tract lacerations and possible damage to the anal sphincter with future risk of fetal incontinence. Newborn complications include birth trauma and hypoxia.

ANALYSIS

Objectives

1. Select a method of management appropriate to the clinical circumstances of this case.
2. Identify the prerequisites for operative vaginal delivery.
3. Be aware of possible complications that may arise.

Considerations

The etiology of the FHR deceleration in this case is uncertain. The differential diagnosis includes abruption of the placenta (made more likely by the woman having severe preeclampsia), an umbilical cord complication (occult compression, tight nuchal cord, true knot in the cord), or often unexplained, even in retrospect. Management depends heavily on the training and experience of the accoucheur, but the best option in this setting is forceps delivery.

APPROACH TO

Operative Vaginal Delivery for Fetal Indication

DEFINITIONS

ENGAGEMENT: The biparietal diameter of the fetal head has passed through the pelvic inlet (inferred clinically when the leading bony edge is at or below zero station).

PROLONGED DECELERATION: A visually apparent decrease in FHR from baseline that is ≥ 15 bpm, lasting ≥ 2 minutes, but < 10 minutes.

LOW FORCEPS DELIVERY: A forceps delivery performed when the leading point of the fetal skull is at station ≥ +2 cm and not on the pelvic floor. Subsets include rotation ≤ 45 degrees (usually straightforward) or > 45 degrees (can be more difficult).

CLINICAL APPROACH

The first task confronting the caregiver is to select a method of management. When the woman is first seen at 3 minutes, conservative measures like turning off the oxytocin, repositioning, and administering oxygen should be tried. However, when the heart rate is still down at 7 minutes, active intervention is warranted. Prematurity is a relative contraindication to vacuum extraction. Midwives and most family physicians are not trained in the use of forceps. Depending on the facility, it may take time to set up for an emergency cesarean delivery and it cannot be known with certainty when or if the FHR will improve. Thus, if the operator has adequate training and experience, forceps delivery is the best option.

Prior to applying the forceps, a quick check should be made to ensure that the prerequisites for forceps delivery (Table 30–1) are satisfied.1 The operator must accurately diagnose the position of the fetal head and apply the forceps accordingly. The application should be checked to ensure that the sagittal

Table 30–1 PREREQUISITES FOR OPERATIVE VAGINAL DELIVERY

Ruptured membranes Complete cervical dilation Engagement of fetal head Known position of fetal head Experienced operator Adequate fetopelvic relationship Informed consent—risks, benefits, alternatives Adequate anesthesia Empty bladder/rectum Appropriate instrument Satisfactory maternal position

suture bisects the plane of the shanks, that the posterior fontanel is one fingerbreadth above the plane of the shanks and that, if a fenestrated blade is used, the operator’s finger cannot be inserted into the posterior aspect of the fenestra (Figures 30–1 and 30–2). Next, any necessary rotation of the head should be accomplished. After rechecking the application, traction can be applied manually using a Pajot-Saxtorph maneuver or a Bill axis traction handle. Given that this case involves a 33-week fetus, descent of the head should be observed on the first traction attempt. Some operators prefer to remove the forceps prior to delivering the head. An episiotomy may or may not be performed according to the judgment of the operator.

For those with training and experience the preceding may seem almost trivial. However, many contemporary training programs do not adequately prepare trainees to confidently and competently perform these procedures. If, instead of the case described, there was a term fetus with a deep transverse

Figure 30–1. Sagittal view of the first blade application. The fetus is presenting as

vertex and with occiput anterior.The application of the left blade Simpson forceps is

shown. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al.

Williams Obstetrics. 23rd ed.New York,NY: McGraw-Hill; 2010.)

Figure 30–2. After the right blade is inserted, and forceps are symmetrically

placed and articulated. (Reproduced, with permission,from Cunningham FG,Leveno KJ,

Bloom SL, et al. Williams Obstetrics. 23rd ed.New York,NY: McGraw-Hill; 2010.)

arrest following a prolonged second stage of labor, the requirement for skill, judgment, and careful assessment of fetopelvic relationships is much more stringent and difficult to achieve. With a forceps delivery rate in the United States of only 1%,2 compared to a cesarean delivery rate of 32%, relatively few individuals acquire and maintain these technical skills.

Once a woman begins the second stage of labor, all types of deliveries have risks. Therefore, it is appropriate to consider the risks and benefits of each possible method of delivery: forceps, vacuum extraction, cesarean, or awaiting spontaneous delivery. For one specific complication of the newborn, intracranial hemorrhage, the risks for forceps, vacuum, and cesarean in the second stage of labor were found to be comparable.3

Maternal risks of operative vaginal delivery include hemorrhage from genital tract lacerations and anal sphincter injury with a future risk of fecal incontinence. These injuries are attributable not only to the instrument itself, but also to the use of the instrument. A case in point would be a laceration of the external anal sphincter caused by prolonged downward traction on the fetal head with forceps. The operator must be cognizant of the fact that the axis of traction must change continuously as the fetal head descends in the pelvis. The same principle applies to vacuum extraction.

Neonatal morbidity associated with operative vaginal delivery can be reduced by employing good judgment and proper technique. Fractures of clavicle and skull, the latter uncommonly, facial nerve and brachial plexus palsies, and the previously cited intracranial hemorrhage all have been associated with instrumental delivery. Subgaleal hemorrhage occurs more often with vacuum extraction than with forceps.4

Faced with a decision between operative vaginal delivery and cesarean delivery, the operator should be reminded that there is more at stake than the current case. If a first delivery is by cesarean, the next is highly likely to be by cesarean as well.5 The incidence of placenta previa, placenta accreta, uterine rupture, and various maternal complications all increase with each successive cesarean. In contrast, if the first delivery is vaginal, the next one is also likely to be vaginal.6

Lastly, even though the case presented would not be appropriate for vacuum extraction (VE), it is evident that VE is on the rise in the United States. When VE is selected for an appropriate case, the operator is advised to pay particular attention to cup position, which should be symmetric and centered approximately 3 cm anterior (toward the fetal face) to the posterior fontanel. VE should not be used for gestations less than 34 weeks. The incidence of shoulder dystocia may be greater with VE than with forceps. As with forceps, good judgment and good technique are essential.

For many reasons, operative vaginal delivery is on the decline in the United States and several other parts of the world. It is being replaced by cesarean delivery despite the lack of evidence that shows an advantage of cesareans to either mothers or babies. Unless physicians receive adequate training in either forceps delivery, vacuum extraction, or both, operative vaginal delivery will no longer be a viable alternate to abdominal delivery.

Comprehension Questions

30.1 What is the range in minutes of prolonged deceleration?

A. 1 to 3

B. 2 to 5

C. 2 to 10

D. 10 to 15

30.2 In the case scenario, which of the following missing pieces of information is most important before proceeding with forceps delivery?

A. Whether there was meconium in the amniotic fluid.

B. The estimated fetal weight.

C. The bispinous diameter of the maternal pelvis.

D. The position of the fetal head.

30.3 When the biparietal diameter of the fetal head has passed through the pelvic inlet, at what station is the leading bony edge usually palpated?

A. −2

B. 0

C. +2

D. +5

30.4 Which of the following statements regarding episiotomy is most accurate when forceps are used?

A. It should be performed routinely.

B. It is seldom indicated.

C. It should be left up to the judgment of the operator.

D. Mediolateral is preferred over midline.

ANSWERS

30.1 C. 2 to 10 minutes: This answer is found in “Definitions” section of the chapter.

30.2 D. An accurate diagnosis of position is most important, although attention should be paid to the other choices also. This answer is found in the second paragraph of “Clinical Approach” and also in Table 30–1.

30.3 B. Zero station. Answer is found in “Definitions” section.

30.4 C. Answer is found in the second paragraph of “Clinical Approach.”

Clinical Pearls

See US Preventive Services Task Force Study Quality levels of evidence in Case 1

➤ Lacerations of the external anal sphincter at forceps delivery are techniquedependent, not simply an inherent risk of the instrument (Level III).

➤ Forceps delivery has some specific indications where VE is not possible, for example, the premature infant (Level III).

➤ Training in forceps techniques is a very important element of all obstetric residency programs (Level III).

➤ All forceps applications should be checked by the most experienced person in the room prior to initiating traction (Level III).

REFERENCES

1. Dennen EH. Forceps Deliveries. Philadelphia, PA: F.A. Davis Company; 1955. 

2. Martin JA, Hamilton BE, Sutton PD et al. Births: Final data for 2005. National Vital Statistics Reports. Hyattsville, MD: NCHS; 2007:56. 

3. Towner D, Castro MA, Eby-Wilkens E, Gilbert WM. Effect of mode on delivery in nulliparous women on neonatal intracranial injury. NEJM. 1999;341(23):1709-1714. 

4. Clinical management guidelines for obstetrician-gynecologists. Operative vaginal delivery. ACOG Practice Bulletin No. 17. Washington, DC: American College of Obstetricians and Gynecologists; June 2000. 

5. Yeomans ER. Operative vaginal delivery. Clinical Obstetrics—The Fetus and Mother. 3rd ed. Malden, MA: Blackwell Publishing; 2007:1077-1084. 

6. Patel RR, Murphy DJ. Forceps delivery in modern obstetric practice. BMJ. 2004;1302-1305.

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