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Vaginal birth has long-term impact on pelvic muscle strength

Robin Wulffson MD's picture
pelvic muscle damage, prolapse, stress incontinence, Kegel exercises

According to a new study, undergoing cesarean births can prevent long-term damage to pelvic muscles. Researchers affiliated with Johns Hopkins School of Medicine published their findings in the November Issue of the journal Obstetrics & Gynecology. Undergoing a cesarean section with its associated risks is not warranted for reducing the risk of pelvic muscle damage; however, a simple exercise is available that can strengthen pelvic muscles.

Pelvic muscle function is a potentially important outcome of childbirth, because muscle weakness is associated with pelvic floor disorders. For example, pelvic muscle strengthening is recommended to reduce urinary incontinence in the postpartum period and later in life. The researchers noted that pelvic muscle strength decreases after childbirth; furthermore, several small studies of postpartum women have shown that pelvic muscle strength is lower after vaginal than after cesarean delivery. They note that the impact on pelvic muscles due to other aspects of childbirth has not been investigated; furthermore, the influence of childbirth on pelvic muscle function has not been studied beyond the immediate postpartum period.

The aim of the study was to estimate the effect of vaginal childbirth and other obstetric exposures on pelvic muscle strength 6 to 11 years after delivery and to investigate the relationship between pelvic muscle strength and pelvic floor disorders.

The study group comprised 666 women who had delivered one or more children. Pelvic muscle strength was measured with a perineometer 6 to 11 years after delivery. (The perineometer is an instrument for measuring the strength of voluntary contractions of the pelvic floor muscles.) Obstetric exposures were classified by review of hospital records. Pelvic floor outcomes, including stress incontinence (loss of urine when coughing, sneezing, or laughing), overactive bladder, anal incontinence, and prolapse symptoms (pelvic organs protruding downward into the vagina), were assessed with a validated questionnaire. Pelvic organ support was assessed using the Pelvic Organ Prolapse Quantification system.

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The researchers found that in comparison with women who delivered all of their children by cesarean, peak muscle strength and duration of contraction were reduced among women with a history of vaginal delivery (39 cm water vs. 29 cm water). Pelvic muscle strength was further reduced with a history of forceps delivery (17 cm water). After vaginal delivery, reduced pelvic muscle strength was associated with symptoms of anal incontinence and pelvic organ prolapse on examination; these associations were not observed among those who had delivered exclusively by cesarean.

These authors concluded that pelvic muscle strength almost a decade after childbirth is affected by vaginal delivery and by forceps delivery. They added that their findings were statistically significant; however, some of the differences observed were small in magnitude.

Take home message:
The perineometer was invented by Dr. Arnold Kegel, an assistant Professor of Gynecology at the University of Southern California School of Medicine. He also invented the Kegel exercises to strengthen the pelvic floor. He first published his ideas in 1948. Kegel exercises are currently recommended by many obstetrician gynecologists. The exercises can improve the strength of pelvic muscles; however, for woman with significant pelvic floor damage, the best option is pelvic surgery. Another option for women with a high surgical risk is a pessary: a device inserted into the vagina to push pelvic organs upward.

How to do Kegel exercises:

  • Find the right muscles. It takes some practice to identify your pelvic floor muscles and learn how to contract and relax them. To identify your pelvic floor muscles, stop urination in midstream. If you succeed, you've found the right muscles.
  • Perfect your technique. Once you've identified your pelvic floor muscles, empty your bladder and lie on your back. Tighten your pelvic floor muscles, hold the contraction for five seconds, and then relax for five seconds. Try it four or five times in a row. Work up to keeping the muscles contracted for 10 seconds at a time, relaxing for 10 seconds between contractions.
  • Maintain your focus. For best results, focus on tightening only your pelvic floor muscles. Be careful not to flex the muscles in your abdomen, thighs or buttocks. Avoid holding your breath. Instead, breathe freely during the exercises.
  • Repeat three times a day. Aim for at least three sets of 10 repetitions a day.
  • Do not make a habit of using Kegel exercises to start and stop your urine stream. Doing Kegel exercises while emptying your bladder can actually weaken the muscles, as well as lead to incomplete emptying of the bladder, which can increase the risk of a urinary tract infection.

Reference: Obstetrics & Gynecology



Elective cesarean can be advantageous especially after an already traumatic vaginal birth. Someone who had a third or fourth degree tear, or an anal fissure or anal fistula repair should consider an elective cesarean to avoid further damage.
Unfortunately, the damage has already been done. The obstetrician needs to determine whether a second vaginal birth would result in more damage. The risk of an elective cesarean at term has less risk than one performed after a long, hard, labor. A long, hard labor followed by a vaginal birth has increased risk. In my opinion, if a woman prefers a cesarean and is apprised of the pros and cons, she should be allowed to have one.