Research and Evidence
NOTE: For guiding care, Childbirth Connection gives priority to systematic reviews. These rigorous summaries of best available evidence are the most trustworthy way to know the benefits and harms of specific practices.
"Evidence-based maternity care" means using results from the best research about the safety and effectiveness of specific tests, treatments and other interventions to help guide maternity care decisions. The information on this page is based on systematic reviews of the best available research that have been published since 2005. We strongly encourage you to read the Maternity Care section for more information about maternity care decision-making and the importance of best evidence.
A number of labor practices can affect your pelvic floor. The information in this section addresses the relationship between pelvic floor and a number of labor practices, including electronic fetal monitoring, episiotomy, labor pain treatment, vaginal and cesarean birth, pushing and positioning, fundal pressure, and the use of vacuum extraction or forceps.
What is electronic fetal monitoring (EFM)?
An electronic monitor is used to track and show the baby's heart rate as you have contractions, to make sure the baby is doing well. Monitoring can be external, where the heart rate is tracked through an ultrasound device that is fixed to your belly with a belt or band. Internal monitoring may also be used and involves inserting a spiral electrode needle through the vagina and cervix and under the baby's scalp.
What are other ways to monitor the baby's heart rate in labor?
The baby's heart rate can be monitored for a short period at regular intervals (intermittently) by using either the EFM machine, a hand-held device (Doppler) or a special stethoscope. This type of monitoring allows you much more freedom of movement to walk, use the toilet, use a shower or tub and get into more comfortable positions.
How can continuous EFM affect my pelvic floor?
With continuous EFM, a woman is connected to a monitor throughout labor. The theory behind continuous EFM was that it would help the health care team know if something is going wrong with the baby so they could intervene right away, but many studies have shown that babies are not born in better condition with continuous EFM compared with babies who are monitored intermittently. And, a systematic review found that women with continuous EFM were more likely than women with intermittent monitoring to experience assisted vaginal birth with forceps or vacuum extraction. (Cesarean birth was also more likely.)Alfirevic Z., Devane, D., & Gyte, G.M. (2013). Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour. Cochrane Database of Systematic Reviews, 5 (CD006066).
Sometimes electronic fetal monitoring is used for a short period of time as a test just after hospital admission to check on the baby’s well-being. A systematic review found that women with admission EFM were more likely than women with intermittent monitoring to experience assisted vaginal birth with forceps or vacuum extraction. (Cesarean birth was also more likely.)Gourounti, K. & Sandall, J. (2007). Admission cardiotocography versus intermittent auscultation of fetal heart rate: effects on neonatal Apgar score, on the rate of caesarean sections and on the rate of instrumental delivery–a systematic review. International Journal of Nursing Studies, 44(6),1029-35.
These practices have implications for the health of your pelvic floor because assisted vaginal birth increases the chance of a serious tear into or through the anal muscle. Further, assisted vaginal birth has often been combined with midline episiotomy, which increases risk for such tears. Anal muscle tears can lead to leaking gas and, more rarely, feces, or feeling like you urgently have to go to the bathroom. It can also increase the likelihood of pain during sexual intercourse.
When is continuous EFM generally recommended?
Continuous EFM is standard practice with some situations that increase the likelihood that a baby will have certain problems, including when:
- Synthetic oxytocin (Pitocin or "Pit") is given by intravenous (IV) drip to start or strengthen labor.
- Epidural analgesia is used for pain relief.
- A woman labors with the aim of vaginal birth after cesarean (VBAC) – this involves EFM because a sudden drop in the baby's heart rate is the most reliable sign that the scar from a previous C-section has opened and is causing the baby problems.
In some settings, women have access to “telemetry,” which allows them to both move about and be continuously monitored via signals sent to a base location in the labor unit. Some telemetry monitors are waterproof for use in tubs or showers. You can ask if telemetry is available if you plan to experience or are experiencing these situations.
If these situations do not apply, talk to your doctor or midwife and the nursing staff at your place of birth – in advance and again during labor – about monitoring the baby intermittently whenever possible.
What is an episiotomy?
An episiotomy (uh-pee-zee-ot-uh-mee) is a cut made in the back of the opening of the vagina to enlarge it for birth just as the baby’s head is ready to be born. With midline or median episiotomy, the most common type in the United States and Canada, the cut is made from the back of the vaginal opening straight toward the anus. With mediolateral episiotomy (most common in the rest of the world), the cut is made off to one side. The two illustrations below show the anatomy of the pelvic floor (left drawing--coming soon!) and the two episiotomy cutting types (right drawing--coming soon!).
In the past, many care providers believed that episiotomies improved birth outcomes. In response to best evidence and professional recommendations, the percentage of women with episiotomies among women who give birth vaginally has fallen steadily in recent decades in the United States. However, the rate is still too high. Currently, about 1 in 10 women with a vaginal birth has an episiotomy. Episiotomy rates vary widely across care providers and across birth settings; studies show that half or more of current episiotomies could be safely avoided.
How does having an episiotomy affect my pelvic floor?
A large body of consistent research has shown that routine use of episiotomy actually promotes rather than prevents pelvic floor problems. Episiotomy offers no advantages over the spontaneous tissue tears that may occur during birth.
Midline episiotomy, most common in the United States, actually increases the risk for tears into or through the anal muscle. Many anal muscle tears that occur during birth are extensions of midline episiotomies.
With mediolateral episiotomy, muscle fibers are more vulnerable (see the Pelvic Floor Anatomy illustration above). This type of cut (primarily used outside the United States and Canada) can involve a longer, more painful healing period, scarring and sometimes a scar with uneven healing that pulls to one side.
What are the effects of episiotomy?
Both types of episiotomy can injure your perineum (the tissue between the vagina and the anus). Episiotomy increases risk for several problems:
- A systematic review found that midline episiotomy increased risk for perineal tear.Villot, A., Deffieux, X., Demoulin, G., Rivain, A.L., Trichot, C., & Thubert, T. (2015). Management of third and fourth degree perineal tears: A systematic review [Article in French]. Journal de Gynécologie Obstétrique et Biologie de la Reproduction, 44(9), 802-11.
- A systematic review of both types of episiotomy found more liberal versus more restrictive use resulted in more severe perineal trauma; stitching and healing complications; and no difference in pain with intercourse, urine leakage or several pain measures. The authors report that results for midline episiotomies are similar to overall results.Carroli, G. & Mignini, L. (2009). Episiotomy for vaginal birth. Cochrane Database of Systematic Reviews, 1 (CD000081).
- A systematic review combining studies with both types of episiotomy found this procedure increased risk for serious tears that extend into or through the anal muscle.LaCross, A., Groff, M., & Smaldone, A. (2015). Obstetric anal sphincter injury and anal incontinence following vaginal birth: a systematic review and meta-analysis. Journal of Midwifery & Women's Health, 60(1), 37-47.
- A systematic review of both types of episiotomy found that common versus more limited use of episiotomy offered no benefit, including for injury, pain, incontinence, sexual function or pelvic floor relaxation.Hartmann, K., Viswanathan, M., Palmieri, R., Gartlehner, G., Thorp, J., & Lohr, K.N. (2005). Outcomes of Routine Episiotomy: A Systematic Review. JAMA, 293(17), 2141-2148.
Episiotomy is often used with assisted vaginal birth (use of forceps or vacuum extractor to help the baby out at the time of birth). However, current research does not support this: A systematic review found greatly increased risk of severe tears into the anal muscle when the standard United States midline episiotomy was used with vacuum-assisted birth.Sagi-Dain, L. & Sagi, S. (2015). Morbidity associated with episiotomy in vacuum delivery: a systematic review and meta-analysis. BJOG, 122(8), 1073-81.
What are the effects of anal muscle tears?
Anal muscle tears involve more severe injury than shorter tears. The healing process is generally longer than with shorter tears or stretching of tissue with no tear. Two systematic reviews have found that tears into or through the anal muscle increase a woman’s likelihood of experiencing anal incontinence (unintended loss of stool or gas).Bols, E.M., Hendriks, E.J., Berghmans, B.C., Baeten, C.G., Nijhuis, J.G., & de Bie, R.A. (2010). A systematic review of etiological factors for postpartum fecal incontinence. Acta Obstetricia et Gynecologica Scandinavica, 89(3), 302-14;LaCross, A., Groff, M., & Smaldone, A. (2015). Obstetric anal sphincter injury and anal incontinence following vaginal birth: a systematic review and meta-analysis. Journal of Midwifery & Women's Health, 60(1), 37-47.
When might episiotomy be recommended?
About the only reason most providers would agree that an episiotomy is appropriate is when the baby is close to being born and an urgent problem develops.
When examined in individual scientific studies, none of the following reasons that are often given for episiotomy have sufficient evidence behind them. If your care provider offers one of these reasons, you may want to question him or her and push back.
- You’re a first-time mother. Studies that attempt to restrict episiotomy do not find that having a first baby is, in and of itself, a reason for episiotomy.
- Your provider believes a tear is about to occur. Performing an episiotomy for this reason has not been shown to have a protective effect.
- You are having a vacuum extraction or forceps delivery. Women are much less likely to have anal muscle injuries if they don't have a midline episiotomy with an assisted vaginal birth.(Mediolateral episiotomy neither prevents nor causes anal injury compared with no episiotomy.)
- You or your provider believes that episiotomy prevents pelvic floor weakness. Women are just as likely to have weak pelvic floors or urinary incontinence in the early months after childbirth with or without an episiotomy. In fact, women who don’t get an episiotomy and have no or only a tiny tear at birth have the strongest pelvic floors, while women with tears into the anal muscle have the weakest pelvic floors. Women with spontaneous tears do just as well as, or better than, women with episiotomies.
- Your provider believes that episiotomy is easier to repair (to stitch closed) than a tear. No research supports this claim. With optimal care, many women will need no more than a few stitches or no stitches at all.
- You or your provider believes that episiotomy heals better. An episiotomy of either type is more likely to have delayed healing or to become infected in comparison with no episiotomy. A mediolateral episiotomy is more likely to scar and heal pulled to one side compared with the tears that may occur with no episiotomy.
How can I reduce my risk of having an episiotomy?
To avoid an unneeded episiotomy, it is important to understand the practice style of those who might attend your birth.
- Talk with your care provider about limiting episiotomy to medically urgent situations. Research does not support cutting an episiotomy to:
- Prevent tears into the anal muscle
- Prevent pelvic floor problems
- Enable easier repair (stitching) than a tear
- Promote better healing than a tear
- Avoid problems in first-time mothers
- Avoid problems if your baby seems to be large
- Avoid problems if your care provider thinks that a tear in the perineum is about to occur
- Talk with your caregiver about not using an episiotomy, should an assisted vaginal birth become necessary. Not having an episiotomy with a vacuum extraction or forceps delivery greatly reduces the likelihood that you will have a tear into the anal muscle.
- Designate someone on your support team to remind you to remind your birth attendant when it comes time for the birth that you don't want an episiotomy, and clearly express your wishes at that time.
What happens after getting a tear or an episiotomy?
Smaller tears (“first degree”) heal best on their own without any stitching. After the birth, care providers will numb the area with an analgesic drug and stitch a larger tear or an episiotomy for best healing. Your care provider will advise you about ways to promote comfort and healing.
Serious tears (into or through the anal muscle — known as third- and fourth-degree tears) happen in about 5 percent of vaginal births. These take longer to heal and may involve much discomfort. They also increase risk of developing anal incontinence, the unintended release of gas or stool. Avoiding such practices as episiotomy, assisted birth and fundal pressure reduces this risk for serious tears.
How can having an epidural affect my pelvic floor?
Having epidural analgesia to relieve labor pain can lead to pelvic floor harm because it increases the likelihood of vacuum extraction or forceps birth (assisted vaginal birth).
Epidurals may have this effect because they numb women from the belly down, making it more difficult both to push effectively and to get into upright positions that can help move the baby out. A systematic review found that epidural analgesia increased the likelihood that a woman would experience assisted vaginal birth.Anim-Somuah, M., Smyth, R.M., & Jones, L. (2011). Epidural versus non-epidural or no analgesia in labour. Cochrane Database of Systematic Reviews, 12 (CD000331).
Assisted birth, which is often used with midline episiotomy (cutting straight toward the anus to enlarge the vaginal opening at the time of birth), increases the chance of a tear into or through the anal muscle. Anal muscle tears can lead to bowel incontinence (leaking gas or feces or a sense of urgency about elimination) as well as increased likelihood of pain during sexual intercourse.
We encourage you to visit the Labor Pain section of this website for much more information on possible harms and benefits of epidural and other labor pain relief options.
Is there a difference in incontinence between women who have had vaginal and cesarean births?
The best available evidence has found no difference in anal incontinence (leakage of stool or gas), in urge urinary incontinence (leakage of urine with a sense of “got to go”), and in any severe urine leakage.
In the short and long term, women with vaginal birth have been found to be more likely to experience stress urinary incontinence (leakage with exertion). Current studies cannot clarify whether this difference is related to vaginal birth itself or to practices that are common with vaginal birth. Examples of concerning practices include assisted vaginal birth (with vacuum extraction or forceps) and common interventions that make these more likely (e.g., epidural analgesia, continuous electronic fetal monitoring), staff pushing on your upper belly to move the baby out and episiotomy (a cut just before birth to enlarge the opening of the vagina). Here is best current evidence about this topic:
- A systematic review found that, in the short term, there was no difference in urine leakage with a sense of urgency or any severe urine leakage between women with cesarean and vaginal births. However, in the short term, women with cesarean births were less likely to experience urine leakage with exertion.Press, J.Z., Klein, M.C., Kaczorowski, J., Liston, R.M., & von Dadelszen, P. (2007). Does cesarean section reduce postpartum urinary incontinence? A systematic review. Birth, 34(3), 228-37.
- A systematic review found that a year or more after birth, about eight percent more women with a vaginal birth experienced urine leakage with exertion, and about three percent more women with vaginal birth experienced urine leakage with a sense of urgency, compared to women with cesarean birth.Tähtinen, R.M., Cartwright, R., Tsui, J.F., . . . & Tikkinen, K.A. (2016). Long-term Impact of Mode of Delivery on Stress Urinary Incontinence and Urgency Urinary Incontinence: A Systematic Review and Meta-analysis. European Urology, February, S0302-2838(16)00156-1.
- A systematic review did not find a difference in anal incontinence, either loss of stool or gas, between women with vaginal and cesarean births.Nelson, R.L., Furner, S.E., Westercamp, M., & Farquhar, C. (2010). Cesarean delivery for the prevention of anal incontinence. Cochrane Database of Systematic Reviews, 2 (CD006756).
Does cesarean or vaginal birth impact my likelihood of experiencing pelvic organ prolapse?
At this time, we do not know whether vaginal and cesarean births differ in the likelihood that your uterus and other inner organs will sag into your vagina (prolapse). Limited studies in one systematic review suggest that women with vaginal birth may be more likely to experience prolapse than women with cesarean birth.Vergeldt, T.F., Weemhoff, M., IntHout, J., & Kluivers, K.B. (2015). Risk factors for pelvic organ prolapse and its recurrence: a systematic review. International Urogynecology Journal, 26(11), 1559-73. However, this body of evidence is small and does not lead to a clear conclusion, and these researchers have not evaluated the role of healthy versus commonly concerning vaginal birth practices such as staff directing you to push forcefully, staff pushing on your upper belly to move the baby out, and episiotomy.
Is there a difference in sexual dissatisfaction or pain with intercourse between women with vaginal and cesarean births?
We did not find any systematic reviews that address these questions.
I had an anal muscle tear at my last birth. What should I think about this time?
Because serious tears into the anal muscle are painful and can lead to bowel incontinence, it is important to avoid them. A systematic review found that risks for another tear into the anal muscle are increased with assisted vaginal birth (with forceps or vacuum extraction) and when the previous tear was “fourth-degree” (all the way through the anal muscle).Jha, S. & Parker, V. (2015). Risk factors for recurrent obstetric anal sphincter injury (rOASI): a systematic review and meta-analysis. International Urogynecology Journal, December, 1-9. Episiotomy is also associated with increased risk for tears into the anal muscle.LaCross, A., Groff, M., & Smaldone, A. (2015). Obstetric anal sphincter injury and anal incontinence following vaginal birth: a systematic review and meta-analysis. Journal of Midwifery & Women's Health, 60(1), 37-47;Villot, A., Deffieux, X., Demoulin, G., Rivain, A.L., Trichot, C., & Thubert, T. (2015). Management of third and fourth degree perineal tears: A systematic review [Article in French]. Journal de Gynécologie Obstétrique et Biologie de la Reproduction, 44(9), 802-11.
Are there any circumstances when I should consider elective C-section?
>p>A difficult vacuum extraction or forceps delivery would increase your risk for pelvic floor injury, so if you are facing this situation near the end of labor, you may prefer to assume the risks of a C-section.
How does pushing position affect my pelvic floor?
As discussed in the Labor Pain section, using epidural analgesia for pain relief has a big impact on the experience of labor. When the cervix is fully open and it is time for the baby to be born, epidurals reduce sensation and a woman’s ability to push well. In this context, varying the position for giving birth has not been shown to make a difference in pelvic floor health. A systematic review of women with epidurals found no evidence that upright versus lying down positioning affected pelvic floor outcomes.Kemp, E., Kingswood, C.J., Kibuka, M., & Thornton, J.G. (2013). Position in the second stage of labour for women with epidural anaesthesia. Cochrane Database of Systematic Reviews, 1 (CD008070).
By contrast, women who do not use epidurals are better able to feel their babies coming down and to push more effectively. Without the limits of epidurals, positioning at the time of pushing can make a difference in your birth outcome. Being upright (e.g., sitting, squatting, kneeling or using a birth stool or chair) offers advantages for your pelvic floor and baby in comparison with lying down (on your back and possibly with your feet in stirrups). A systematic review of women without epidurals found that upright positions reduced the likelihood of having assisted vaginal birth (with vacuum extraction or forceps), episiotomy, and abnormal fetal heart rate patterns. Being upright had the trade-off of involving more “second-degree” tears (not extending into anal muscle) and more excess blood loss greater than 500 centimeters.Gupta, J.K., Hofmeyr, G.J., & Shehmar, M. (2012). Position in the second stage of labour for women without epidural anaesthesia. Cochrane Database of Systematic Reviews, 5 (CD002006).
How does pushing timing affect my pelvic floor?
For many decades, a common practice has been to coach women to push as soon as the opening of the uterus (cervix) is fully stretched (dilated). This is because people used to believe that it was better for the baby if the pushing stage were as short as possible. More recently, studies have begun to look at when women should push (when the cervix is fully opened vs. when a woman experiences her own urge to push).
The pressure of the baby's head deep against your pelvic floor stimulates an innate pushing reflex ("urge to push"). When women follow their own inner sensations, they often don't begin pushing until sometime after the cervix is fully opened. When they do bear down, pushes tend to last only a few seconds, and many women grunt or groan while they push. These differences may explain why you would be less likely to be injured or need stitches. Pushing in this manner allows the vaginal tissues to gently spread out around the baby's descending head. Pushing this way may also avoid overstretching pelvic floor ligaments and muscles. We cover this issue in more detail in the Planning Ahead page within this section.
At this time, a systematic review has only examined whether timing of pushing makes a difference in women with epidurals. A systematic review of women with epidurals found that there was no difference in early or delayed pushing with respect to perineal tears and episiotomy. Women with delayed pushing were more likely to have a “spontaneous” vaginal birth (without use of vacuum extraction or forceps).Lemos, A., Amorim, M.M., Dornelas de Andrade, A., de Souza, A.I., Cabral Filho, J.E., & Correia, J.B. (2015). Pushing/bearing down methods for the second stage of labour. Cochrane Database of Systematic Reviews, 10 (CD009124).
Pushing position can impact favorable outcomes when epidural analgesia is not used, but whether timing of pushing can similarly impact favorable outcomes when women do not use epidural analgesia cannot be answered at this time.
How does pushing method affect my pelvic floor?
The common practice has been to tell women to bear down and push long and hard during contractions (sometimes called “Valsalva” or "purple pushing"). This is because people used to believe that it was better for the baby if the pushing stage was as short as possible (and perhaps also because women were heavily drugged during labor). More recently, studies have begun to examine how to push (staff-directed vs. according to a woman’s innate rhythmic pushing reflexes and preferences).
Two systematic reviews have examined how staff- and women-directed pushing differs:
- A systematic review combined studies of women with and without epidurals and found no difference in impact of staff- versus woman-directed pushing on perineal tears, episiotomy or the well-being of the baby.Lemos, A., Amorim, M.M., Dornelas de Andrade, A., de Souza, A.I., Cabral Filho, J.E., & Correia, J.B. (2015). Pushing/bearing down methods for the second stage of labour. Cochrane Database of Systematic Reviews, 10 (CD009124).
- Another systematic review was limited to several smaller studies of women without epidural analgesia. The review found no differences in women with staff- or self-directed pushing for assisted vaginal birth, stitching of tears or episiotomy or newborn outcome. While staff-directed pushing offered no benefit to the woman or her baby, signs of longer-term damage to the pelvic floor warrant more research. The authors recommend supporting women’s own spontaneous pushing efforts and preferences.Prins, M., Boxem, J., Lucas, C., & Hutton, E. (2011). Effect of spontaneous pushing versus Valsalva pushing in the second stage of labour on mother and fetus: a systematic review of randomised trials. BJOG, 118(6), 662-70.
When might a specific pushing position or technique be recommended?
Women who have epidurals will usually be more limited in what positions they can use. If you have an epidural, you may need caregiver-directed coaching during pushing because you’ll be numb.
Your doctor or midwife might recommend a specific position if there are any special concerns about you or your baby. For example, squatting may be problematic for women with varicose veins because it can constrict blood flow from her legs. If there is a medical reason to deliver the baby quickly, you might be told to push forcefully.
What's the connection between assisted vaginal birth and pelvic floor problems?
In an assisted vaginal birth, the provider uses vacuum extraction or forceps to help bring the baby out. The vacuum extraction device uses suction to hold a cap onto the baby's head. The cap is attached to a handle, which the care provider pulls while the mother pushes. In a forceps-assisted birth, the doctor inserts curved blades on either side of the baby's head, locks them together, and pulls.
Vacuum extraction is much less likely to result in deep tears and other tissue injuries than forceps delivery. For this reason, most assisted vaginal births in the United States use vacuum extraction. Assisted vaginal birth increases the likelihood of having a tear into or through the anal muscle. Additionally, a systematic review found that use of midline episiotomy with vacuum-assisted vaginal birth greatly increases the likelihood of serious tears into the anal muscle.Sagi-Dain, L. & Sagi, S. (2015). Morbidity associated with episiotomy in vacuum delivery: a systematic review and meta-analysis. BJOG, 122(8), 1073-81.
In individual studies, having an assisted vaginal birth (with vacuum extraction or forceps) rather than a spontaneous vaginal birth (with neither procedure) increases risk for various types of problems in women. Few systematic reviews have investigated these problems:
- A systematic review found that forceps were associated with increased likelihood of having a perineal tear.Villot, A., Deffieux, X., Demoulin, G., Rivain, A.L., Trichot, C., & Thubert, T. (2015). Management of third and fourth degree perineal tears: A systematic review [Article in French]. Journal de Gynécologie Obstétrique et Biologie de la Reproduction, 44(9), 802-11.
- A systematic review of women with an anal tear in previous birth found that both forceps and vacuum extraction increased the likelihood of again having such an injury.Jha, S. & Parker, V. (2015). Risk factors for recurrent obstetric anal sphincter injury (rOASI): a systematic review and meta-analysis. International Urogynecology Journal, December, 1-9.
What's the connection between fundal pressure and pelvic floor problems?
Fundal pressure is when someone on the health care team presses on a woman's abdomen to help move the baby out. This practice has not been adequately studied. What we did find is:
- A systematic review that found that fundal pressure is associated with increased risk for perineal tear;Villot, A., Deffieux, X., Demoulin, G., Rivain, A.L., Trichot, C., & Thubert, T. (2015). Management of third and fourth degree perineal tears: A systematic review [Article in French]. Journal de Gynécologie Obstétrique et Biologie de la Reproduction, 44(9), 802-11. and
- A systematic review with a single study of fundal pressure applied through an inflatable belt that found it was associated with increased risk of tears into the anal muscle.Verheijen, E.C., Raven, J.H., & Hofmeyr, G.J. (2009). Fundal pressure during the second stage of labour. Cochrane Database of Systematic Reviews, 4 (CD006067).
When might an assisted vaginal birth be recommended?
Your doctor or midwife might recommend assisted vaginal birth if the pushing phase of giving birth has gone on for a very long time and progress in getting the baby to come out is stalling. (Keep in mind that many first-time mothers take about two hours to birth the baby once they begin pushing, and women who have had a vaginal birth before take about an hour. With use of epidural analgesia, the time may be much longer than these norms.)
Another reason assisted vaginal birth may be recommended is if the baby is close to being born and an urgent problem develops, or the head needs to be shifted into a better position for birth.
If you will be having an assisted vaginal birth, ask your care provider to avoid an episiotomy; this will make tears into the anal muscle less likely to occur. When a difficult assisted vaginal birth is expected, you are at greater risk for pelvic floor injury. In this case, you may wish to weigh the pros and cons of assisted vaginal birth vs. having a C-section.
What increases the likelihood of having assisted vaginal birth?
Some widely used labor practices increase your risk for assisted vaginal birth:
- A systematic review found that epidural analgesia for labor pain relief increased the likelihood that a woman will have assisted vaginal birth.Anim-Somuah, M., Smyth, R.M., & Jones, L. (2011). Epidural versus non-epidural or no analgesia in labour. Cochrane Database of Systematic Reviews, 12 (CD000331).
- A systematic review found that continuous electronic fetal monitoring increased the likelihood of vaginal birth with forceps or vacuum extraction.Alfirevic Z., Devane, D., & Gyte, G.M. (2013). Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour. Cochrane Database of Systematic Reviews, 5 (CD006066). Similarly, assisted vaginal birth is more likely in women who experience a short trial period of electronic fetal monitoring just after hospital admission.Gourounti, K. & Sandall, J. (2007). Admission cardiotocography versus intermittent auscultation of fetal heart rate: effects on neonatal Apgar score, on the rate of caesarean sections and on the rate of instrumental delivery–a systematic review. International Journal of Nursing Studies, 44(6),1029-35.
How do vacuum extraction and forceps compare?
There are some clear differences in possible benefits and harms of the two approaches. A systematic review found that forceps are more likely to result in vaginal birth than vacuum extraction. However, forceps are also more likely to involve trauma in women (serious tears into or through the anal muscle, with and without episiotomy), and injury to the baby’s face. Vacuum extraction with metal cup is more likely to result in vaginal birth and more likely to injure the baby’s head than vacuum extraction with a soft cup.O'Mahony, F., Hofmeyr, G.J., & Menon, V. Choice of instruments for assisted vaginal delivery. Cochrane Database of Systematic Reviews, 11 (CD005455).
Why are professional societies recommending greater use of assisted vaginal birth?
Since the mid-1990s, the U.S. cesarean section rate rose as the rate of vaginal births with either vacuum extraction or forceps steadily fell. With increasing recognition of the shorter- and longer-term harms of cesarean birth to both a woman and her baby (or babies in future pregnancies) and overuse of these procedures, there is broad agreement that the cesarean rate can and should be safely reduced. Professional societies have begun to call for increased, cautious use of vacuum extraction and forceps as a way to help some women avoid cesarean birth.