PREVENTING PERINEAL LACERATIONS

Preventing perineal lacerations during labor

By Jay Goldberg, MD, and Carmen Sultana, MD

Using a technique called super crowning, avoiding episiotomy, and reaching for a vacuum device rather than forceps during operative vaginal deliveries are among the strategies that can help reduce the number of third- and fourth-degree lacerations.

Although damage to the vaginal and perineal tissues and anal sphincter often occurs during vaginal delivery, many clinicians don't think of them as significant risks to a woman's health, at least not compared to labor complications like postpartum hemorrhage, pulmonary embolism, and infection. But the truth is such tissue damage can have profound long-term effects.

The process of vaginal delivery, especially when accompanied by episiotomy or operative vaginal delivery, can tear vaginal attachments, rupture the anal sphincter, and cause pudendal nerve damage, which in turn can lead to incontinence and pelvic floor prolapse. And third- or fourth-degree lacerations, those involving the anal sphincter, have been independently linked to bowel incontinence.¹ Risk factors for these severe lacerations include race, first delivery, fetal macrosomia, operative vaginal delivery, long duration of second stage, occiput posterior position, and episiotomy.^2-4

Of course, some of these risk factors can't be modified, but others can. Our purpose here is to review the connection between pregnancy, delivery, and pelvic floor damage, specifically damage to the perineum and anal sphincter. We'll discuss obstetric risk factors for pelvic trauma, preventative strategies, and review the evidence guiding clinical labor management.

Try to avoid episiotomy

In the early 20th century, as deliveries moved from the home to the hospital, episiotomies became a standard part of most vaginal deliveries. Midline episiotomy, the focus of this review, continues to be the predominant type used in the United States. In the past, experts believed that the procedure minimized the risk of pelvic lacerations, infection, neonatal brain injury, and postdelivery pain. Additionally, by shortening the second stage of labor, they theorized that an episiotomy prevented pelvic floor damage, reducing the threat of incontinence and pelvic organ prolapse.

However, Thacker and Banta's landmark paper in 1983, which comprehensively reviewed the literature on episiotomy, found scant evidence to support its usage.⁵ In fact, they offered data to suggest that the procedure may actually do more harm than good. Numerous studies over the last 20 years, including several randomized trials, have shown that episiotomy is usually unnecessary, potentially harmful, and best avoided, when possible. Rather than decreasing pelvic lacerations, midline episiotomy significantly increases the rate of severe (third- or fourth-degree) lacerations, and the potential sequelae of rectovaginal fistula and anal incontinence four- to tenfold. In one audit of medical procedures done at Thomas Jefferson University Hospital, for instance, we found that among 13,759 white women, 15.1% of those who had had an episiotomy developed severe perineal tears, compared to only 4.3% among women who did not have the procedure. We reported similar disparities among blacks, Asians, and Hispanics.³

Additionally, women experience greater rates of infection, delayed healing, increased pelvic pain, and delayed time until resuming sexual relations after an episiotomy. Similarly, studies that looked at the effects of episiotomy on the neonate and on the pelvic floor have found no benefit.^3-5

Of course, there are times when episiotomy is the right choice. Often, operative vaginal delivery requires an episiotomy if crowning has not yet caused vaginal and perineal tissue to become more pliable. Likewise, in the presence of a nonreassuring fetal heart rate (FHR) tracing, episiotomy helps shorten the second stage of labor. Likewise, maneuvers to relieve shoulder dystocia may be easier to perform once an episiotomy has been performed. But since a shoulder dystocia is usually attributable to the bony pelvis rather than soft tissues, episiotomy is usually unnecessary.

Overall, episiotomy rates seem to be decreasing in the US. Between 1983 and 2000, the rates at Thomas Jefferson University Hospital in Philadelphia dropped from 70% to 19%. The rate in 2004 is less than 5%. Similarly, the national rate of episiotomy decreased between 1979 and 1997, from 65.3% to 38.6% for vaginal deliveries. The decrease is probably attributable in large part to incorporation of evidence-based practice, as well as patient preference.^2,6

Making clinicians accountable

One of the most commonly performed surgical procedures, episiotomy is probably the only one done without first obtaining the patient's consent. While obstetrical procedures like amniocentesis, cesarean section, forceps, and vacuum assistance require documentation of an indication, this is currently not required for episiotomy. A recent investigation suggests a way to change this.

During the Philadelphia Episiotomy Intervention Study, researchers inserted an Episiotomy Indication Template in the delivery database at community hospitals. The template asks clinicians to document the reason for each episiotomy they did. In the end, this approach resulted in a significant reduction in episiotomy rates over 1 year. For spontaneous vaginal deliveries, a 33% decrease was observed as episiotomy rates decreased from 39% to 26% (95% CI —18.6 to —7.6%, P <0.001). Forcing the delivering obstetricians to think about, document, and potentially justify why they were actually performing this nonrecommended, potentially morbid procedure immediately lowered episiotomy rates.⁷

Try super crowning

We've found that a technique we call super crowning can decrease vaginal lacerations at the time of delivery (Figure 2). At the time of normal crowning, instead of either allowing the head to spontaneously deliver or pushing back the stretched vaginal tissues to more rapidly deliver the fetal head, super crowning slightly prolongs the crowning portion of the second stage of labor for one or two additional contractions by gently applying counter pressure to the crowning head.

By allowing collagen and other connective tissues more time to naturally and slowly stretch, vaginal lacerations—and especially third- and fourth-degree tears—are significantly reduced. We do not recommend super crowning, however, if a nonreassuring FHR tracing is present or there is some other obstetric situation that requires expedited delivery. No randomized trials have been performed to date on this technique.

Tips for a safer operative vaginal delivery

According to the National Hospital Discharge Summary, of the 602,000 operative vaginal deliveries performed in 2000, 112,000 (19%) were done with forceps and 490,000 (81%) were vacuum-assisted deliveries. It's likely that the vacuum device is replacing forceps for several reasons, including a lack of forceps training in many residency programs and medicolegal considerations. It may also be the result of the emerging research suggesting forceps cause more pelvic floor damage.

Despite its benefits, operative vaginal delivery is associated with greater vaginal and anal sphincter trauma than spontaneous vaginal delivery. In a large retrospective study of over 34,000 vaginal deliveries at Thomas Jefferson University Hospital, we found third- and fourth-degree lacerations following 6.9%, 15.8%, and 31.7% of spontaneous vaginal, vacuum, and forceps deliveries, respectively.³ A randomized trial of obstetric forceps and vacuum deliveries found significantly higher rates of severe vaginal lacerations in the forceps group (29%) compared to the vacuum group (12%).⁸ Another study found higher rates of anal sphincter defects and defecatory symptoms following forceps (81% and 38%) delivery compared to vacuum delivery (21% and 12%).⁹ A significant contributor to the tears associated with operative vaginal deliveries may be midline episiotomy, which accompanies the majority of them. Mediolateral episiotomy may be preferable to midline in this setting, perhaps protecting against tears involving the anal sphincter.

There are several reasons why forceps may cause more pelvic floor damage than a vacuum device. There may be more potential for damage with inappropriate technique, and the widened, rigid diameter of a metallic forceps cradling the fetal head as it descends through the pelvic outlet may also do some damage. The vacuum occupies no additional space when placed on the flexion point of the fetal head, often allowing it to naturally rotate during descent toward the position of least resistance.

To decrease forceps-associated pelvic trauma, we gently disarticulate the forceps blades prior to full crowning, but at a station when delivery can be easily completed using a modified Ritgen maneuver, if necessary. Disengagement should not be done at too high a station; that might require reapplication of the forceps or vacuum. In the absence of a nonreassuring FHR tracing or other obstetric situations in which expediting delivery is necessary, we then use super crowning to give the vaginal and perineal tissues additional time to slowly stretch.

The same technique can also be used with vacuum-assisted delivery, by disengaging the vacuum after bringing the fetal head down to a similar station, then using super crowning. The other benefit of such an approach is that it reduces the need for episiotomy. Rates of severe lacerations are therefore decreased with early disengagement of the forceps and vacuum at the proper station without decreasing the primary goal of delivering vaginally.

Be flexible when choosing a birthing position

The literature contradicts itself on whether maternal position affects perineal lacerations. The supine or semi-recumbent position in labor is most common in hospital-based obstetrics, mainly because it makes electronic fetal monitoring easier. Experts have theorized, however, that several other positions can offer benefits during delivery, including lateral recumbent, kneeling, standing, squatting, and positions using equipment such as chairs, stools, and large balls.

While individual studies on positions—including squatting and lateral recumbent positions—have reported reductions in perineal tears, a Cochrane Library review concluded that the maternal birthing position did not affect perineal trauma, recommending that women be allowed to labor in the position most comfortable to them.^10-12

Perineal massage and delayed pushing

Perineal massage has been studied during pregnancy and during labor to determine if the anecdotes suggesting it reduces pelvic trauma can be supported by more rigorous evidence. To date, randomized controlled trials of daily antenatal perineal self-massage have yielded mixed findings. One study found a nonsignificant 6% decrease in birth-related pelvic tears (75% vs. 69%, P <0.07) in nulliparous women.¹³ Another study that evaluated the effects of a 10-minute perineal massage daily from the 34th or 35th week until delivery found it increased the chances of delivering with an intact perineum (15.1% vs. 24.3%) in the first vaginal birth, but had no effect on later births.¹⁴

A randomized controlled trial of massage and stretching the perineum during the second stage of labor with a water-soluble lubricant produced fewer third-degree tears in the intervention group (1.7% vs. 3.6%, RR 0.45), but concluded that the intervention does not increase the likelihood of maintaining an intact perineum or reduce the risk of pain, dyspareunia, or urinary and fecal problems.¹⁵ The other concern is that the technique can cause abrasions, bleeding, and discomfort by itself, especially in the primipara who has developed edematous vaginal tissues.

With delayed pushing, second stage pushing is put off either until there is an irresistible urge to push or when the presenting part has descended to the perineum. Several studies have examined whether this strategy decreases the rate of severe lacerations. Although delayed pushing may have other benefits, these studies agree that it has no effect on the rate of third- and fourth-degree tears.^16-18

In the final analysis

Protecting the pelvic floor and anal sphincter is an important and often overlooked component of labor management. Delivery-associated maternal trauma to the vagina and anal sphincter may have serious long-term consequences, including rectovaginal fistula and anal incontinence. Obstetric procedures that can cause iatrogenic injury, including episiotomy, and forceps and vacuum delivery, are major contributors to this damage, with significantly increased rates of third- and fourth-degree lacerations.

We don't recommend episiotomy, except when expedited delivery is immediately necessary or when it is needed to facilitate operative vaginal delivery. The risk of severe lacerations is much greater when using forceps compared to vacuum. When forceps are used, they should be disarticulated prior to delivery of the fetal head.

Super crowning—slightly prolonging the crowning portion of the second stage of labor for one or two additional contractions by gently applying counter pressure to the crowning head—may decrease the risk of severe tears. Birthing position does not have a significant impact on perineal lacerations and should be left up to the patient and practitioner. Perineal massage, both antenatal and during the second stage of labor, may offer some protection for the perineum. Incorporating some of these techniques into labor management will likely decrease the risk of perineal lacerations.

REFERENCES

1. Fenner DE, Genberg B, Brahma P, Marek L, et al. Fecal and urinary incontinence after vaginal delivery with anal sphincter disruption in an obstetrics unit in the United States. Am J Obstet Gynecol. 2003;189:1543-1549; discussion 1549-1550.

2. Goldberg J, Holtz D, Hyslop T, et al. Has the use of routine episiotomy decreased? Examination of episiotomy rates from 1983 to 2000. Obstet Gynecol. 2002;99:395-400.

3. Goldberg J, Hyslop T, Tolosa JE, et al. Racial differences in severe perineal lacerations following vaginal delivery. Am J Obstet Gynecol. 2003;188:1063-1067.

4. Sultan AH, Kamm MA, Hudson CN, et al. Third degree obstetric anal sphincter tears: Risk factors and outcome of primary repair. BMJ. 1994:308:887-891.

5. Thacker SB, Banta HD. Benefits and risks of episiotomy: an interpretive view of the English language literature, 1860-1980. Obstet Gynecol Survey. 1983;38: 322-338.

6. Weber AM, Meyn L. Episiotomy use in the United States, 1979-1997. Obstet Gynecol. 2002;100:1177-1182.

7. Goldberg J, Fagan M, Roberts N, et al. Reducing episiotomies in Philadelphia through physician education and documentation of indication. International Federation of Gynecology and Obstetrics, XVII FIGO World Congress of Gynecology and Obstetrics; Santiago, Chile; November 3-7, 2003.

8. Bofill JA, Rust OA, Schorr SJ, et al. A randomized prospective trial of the obstetric forceps versus the M-cup vacuum extractor. Am J Obstet Gynecol. 1996;175:1325-1330.

9. Sultan AH, Kamm MA, Bartram CI, et al. Anal sphincter trauma during instrumental delivery. Int J Gynecol Obstet. 1993;43:263-270.

10. Shorten A, Donsante J, Shorten B. Birth position, accoucheur, and perineal outcomes: informing women about choices for vaginal birth. Birth. 2002;29:18-27.

11. Golay J, Vedam S, Sorger L. The squatting position for the second stage of labor: effects on labor and on maternal and fetal well-being. Birth. 1993:20:73-78.

12. Gupta J, Hofmeyr G. Position for women during second stage of labor. Cochrane Database Syst Rev 2004;1: CD002006.

13. Shipman MK, Boniface DR, Telft ME, et al. Antenatal perineal massage and subsequent perineal outcomes: a randomised controlled trial. Br J Obstet Gynaecol. 1997; 104:787-791.

14. Labrecque M, Eason E, Marcoux S, et al. Randomized controlled trial of prevention of perineal trauma by perineal massage during pregnancy. Am J Obstet Gynecol. 1999;180:593-600.

15. Stamp G, Kruzins G, Crowther C. Perineal massage in labour and prevention of perineal trauma: randomised controlled trial. BMJ. 2001;322:1277-1280.

16. Fraser WD, Marcoux S, Krauss I, et al. Multicenter, randomized, controlled trial of delayed pushing for nulliparous women in the second stage of labor with continuous epidural analgesia. The PEOPLE (Pushing Early or Pushing Late with Epidural) Study Group. Am J Obstet Gynecol. 2000;182:1165-1172.

17. Plunkett BA, Lin A, Wong CA, et al. Management of the second stage of labor in nulliparas with continuous epidural analgesia. Obstet Gynecol. 2003;102:109-114.

18. Fitzpatrick M, Harkin R, McQuillan K, et al. A randomised clinical trial comparing the effects of delayed versus immediate pushing with epidural analgesia on mode of delivery and faecal continence. Br J Obstet Gynaecol. 2002;109:1359-1365.

DR. GOLDBERG is a Clinical Assistant Professor and Associate Division Director, Division of General Obstetrics and Gynecology, and DR. SULTANA is an Associate Professor and Residency Director, Department of Obstetrics and Gynecology, Jefferson Medical College, Philadelphia, Pa.

Take-home messages

• Several randomized trials have shown that episiotomy is usually unnecessary, potentially harmful, and best avoided, when possible.

• There are times, of course, when episiotomy is the right choice. Often, operative vaginal delivery requires an episiotomy if crowning has not yet caused vaginal and perineal tissue to become more pliable.

• The vacuum device is probably replacing forceps because of a lack of forceps training in many residency programs and for medicolegal considerations; emerging research also suggests that forceps cause more pelvic floor damage.

• A Cochrane Library review has concluded that the maternal birthing position doesn't affect perineal trauma, recommending that women be allowed to labor in the position most comfortable to them.

Jay Goldberg, Carmen Sultana. Preventing perineal lacerations during labor.

Contemporary Ob/Gyn

Sep. 1, 2004;49:50-58.