Stool Leakage
Stool Leakage

Stool Leakage

Stool leakage, aka fecal incontinence, is one of the most distressing problems that a person who births a child can experience in my opinion. More than urine leakage, it can lead to increased embarrassment, shame, and even isolation as people are fearful to go out in the community. So, read on to see why this typically occurs, and what you can do about it.

By, Stephanie Dillon, PT, DPT, WCS

What is fecal incontinence (FI)?

Similar to urinary incontinence, fecal incontinence is ANY unwanted passage of stool. This can be as small as a tiny bit of smearing in your underwear, to losing fully-formed stool. You can also be incontinent of gas (sometimes called flatal incontinence), where you lose gas when not expecting it. Just a note about terminology here; sometimes FI is also referred to as AI (anal incontinence), or even ABL (accidental bowel leakage). While there can be very small differences in the medical literature on what these terms mean exactly, for the purposes of this article I'm just placing everything into one category—FI.

Why does FI happen?

There can be many reasons why someone may develop FI. It does happen in elderly people for a variety of reasons, but for the purposes of this article we'll be focusing on postpartum FI.

Postpartum FI almost always occurs from what is known as "obstetric anal sphincter injury," which is a mouthful! This is frequently referred to as OASI or sometimes OASIS (for injurieS). Basically all this means is that you had a birth-related tear in your anal sphincter, which is a series of concentric circular muscles that control the opening of the anus. As you can imagine, this tear creates weakness in the anal sphincter, and affects the ability of your sphincter to keep your rectum closed. So, stool and gas can then leak out when you don't want it to. FI affects anywhere from 4-40% of people who give birth, but if you have an OASI, this more than doubles your risk of FI (increases risk by 2.66x).

Why does OASI occur?

There are many reasons why someone may tear through their anal sphincter during a vaginal childbirth.  Typically it is either from natural tearing, or due to further tearing after an episiotomy. There are different grades of tearing as you may or may not be familiar with, so let's do a quick review.

  • Grade 1: Tearing into the perineal skin but not into the perineal muscles. The perineum is the area between the vagina and anus.

  • Grade 2: Tearing into the perineal muscles (halfway from vagina to anus), but not into the anal sphincter.

  • Grade 3: Tearing INTO but not fully THROUGH the anal sphincter. These can also be divided into 3a, 3b, and 3c depending upon whether or not the internal anal sphincter is torn, in addition to the external anal sphincter.

  • Grade 4: Tearing through the anal sphincter into the rectum (the internal and external anal sphincters are fully torn)

So of course as you can imagine, people with grade 3 and 4 tears, or an OASI, are at the greatest risk for fecal incontinence.

How common is OASI?

This is where the data gets a little sticky. The average rate reported of OASI is pretty low, around 3.5% of all vaginal childbirths. However, some studies put the rate as high as 11%. And as you might imagine, the rates vary based on how much training the physician has had to recognize these types of injuries. Plus, really the bigger problem here is that many times OASI is not diagnosed at the time of birth (or under-diagnosed, meaning a grade 3 tear is actually a grade 4). As a result, estimates on the actual rate of OASI can be as high as 26%. This is something we'll talk about a bit later: how to diagnose this type of birth injury, and why it can be difficult to do at the time of delivery. And, of course this rate can vary based on where you live. In the UK for example, there was a threefold increase in the incidence of OASI between 2000 and 2011. This meant 1 in 16 of first-time birthing persons were getting diagnosed with an OASI. Of course that was unacceptable, and so the UK did implement a nationwide strategy to decrease the risk of OASI, which we will talk about later.

What are risk factors for OASI?

There are many pretty well-established risk factors, including:

  • Vaginal delivery using forceps or vacuum --> this is clearly the strongest risk factor across many studies over many years

  • First pregnancy

  • Larger birthweight baby (over 8lbs has a slightly increased risk, over 9lbs a definite risk) & babies with larger heads

  • Episiotomy, especially midline (straight down towards the anus) as opposed to mediolateral (on an angle more towards the thigh)

  • Slight trend towards older age at delivery, especially 34-39 years

  • Vaginal delivery after cesarean birth (VBAC)

  • Procedures used to start/speed-up labor, such as amniotomy (breaking of water), and the use of oxytocin

  • Longer duration of first stage of labor (contractions) and second stage of labor (pushing) 

How is OASI diagnosed after labor?

Most of the time, this is accomplished through careful inspection of the perineum, vagina, and anus after delivery. In order for a thorough examination to take place, you need adequate lighting, exposure of the area, and pain relief for the birthing person. If there is any suspicion of an OASI (grade 3 or 4 tear), then a rectal examination should be performed to rule this in or out. However, there is now some evidence to show that adding an ultrasound to this assessment can show an incidence of missed OASI by anywhere from 12-35%.  Most commonly this type of ultrasound is either done essentially "through" (as in, on top of) the labia, called translabial ultrasound, or inside the vagina—transvaginal. However, the gold standard for diagnosing a grade 3 or 4 tear is something called an endoanal ultrasound, where the probe is placed inside the anus. Despite sounding a little scary or uncomfortable (I'm sure it is uncomfortable to some extent!), this is usually well-tolerated, and gives us the best picture of what is going on with the anal sphincter. However, a recent 2023 study of 680 subjects who received an endoanal ultrasound immediately after birth in the delivery ward shows that it did NOT improve the ability to diagnose an OASI. The study's authors guessed this was mostly due to staff inexperience with using this type of ultrasound, as they were all performed by midwives. So, this may not be useful in maternity wards, but as I said after the fact it is the gold standard to diagnose OASI.

What can we do to prevent OASI during labor?

This is a little less-researched than the diagnosis of and risk factors for OASI. But, a summary of the American College of Obstetricians and Gynecologists (ACOG), plus the Society of Obstetricians and Gynecologists of Canada (SOGC), recommendations on preventing OASI are below:

  • Place a warm compress on the perineum during the pushing phase of labor

  • Slow down the delivery of the baby's head, and instruct the birthing person not to "push" during the delivery of the head (relying upon uterine contractions alone)

  • Perineal massage during the pushing phase of labor

  • Avoid the routine use of episiotomy (hopefully no OBGYNs are doing this anymore!)

  • If episiotomy is needed, then use a mediolateral incision instead of midline

  • If assistance for delivery is needed (i.e. baby is in distress), choose vacuum over forceps

There is limited evidence to show that upright birthing positions (e.g. squatting, kneeling, hands-and-knees) vs. supine birthing positions (laying on your back) has a reduced risk of severe tearing. However, this evidence wasn't sufficient enough to make it into the American or Canadian guidelines for labor. In the UK, as I referenced earlier, a nationwide program was implemented to reduce the rates of OASI. They were able to drop their OASI rates by 20% in just a 2-year period by implementing some of these techniques. They had a four-step program that included:

  • Counseling all prenatal birthing people on OASI risks starting at 32 weeks

  • Manual perineal protection with the doctor or midwife's hand directly on the baby's head and birthing person's perineum during delivery

  • Restricted use of episiotomy (and if needed a 60-degree mediolateral episiotomy was completed)

  • A vaginal AND rectal examination immediately after delivery to assess the extent of any tearing

If I end up an OASI, how is it best treated?

OASI injuries require a surgical repair. Most commonly, this is done by the OBGYN in the delivery ward. However, there has been more scrutiny of this in recent years, identifying that some surgeons are better-suited to repair these types of tears than others. A recent (small) 2023 study that specifically examined the skill of the surgeon found that only 4% of OASI repairs done by a skilled surgeon reported pelvic floor dysfunction after surgery, while a whopping 82% of those who had a less-skilled surgeon reported pelvic floor dysfunction post-operatively.

Minimally, you need good lighting and someone skilled in repairing the anal sphincter. A delivery ward is not the same as an operating theater, and yet most of the time these repairs are done in the delivery room, likely due to cost and accessibility of operating rooms at the time of birth. In many larger hospitals, a more-skilled GYN will be called in to repair the OASI, or they may even delay the repair until a urogynecologist or colorectal surgeon is available. You can delay these surgeries for 8-12 hours after birth without any negative consequences. Many international governing bodies of women's health are now recognizing the repair of an OASI does really require extra training of whomever is repairing it. In my opinion they absolutely should not be done by GYN residents, plus they are definitely out of the scope of practice for midwives. Most of the guidance provided by these organizations are calling for more training in the surgeons who are performing OASI repairs, but stop short of recommending they are all done by a urogynecologist or colorectal surgeon. But if you have that option, definitely take it! And/or at least request a highly-trained GYN who has done many of these repairs to fix your OASI.

Yikes, if I had a 3rd or 4th-degree tear repaired by my GYN, should I be concerned?

Not necessarily. It really depends upon the skill of your GYN, and then whether or not you are having symptoms after surgery. And please don't misunderstand me—I am not trying to throw your (or any!) GYN under the bus here! It's just that GYNs have to wear so many hats, from well-woman care, to abdominal surgeries for things like endometriosis, to caring for a pregnancy and knowing how to delivery a baby vaginally or via C-section, to hormone replacement and care into menopause, etc. It makes sense that something as delicate as the anal sphincter may require more training & skill that some GYNs may possess. So, basically, if you had a 3rd or 4th-degree tear (an OASI), and you are still struggling with stool leakage after 6 weeks postpartum, I would highly recommend you see a colorectal surgeon. They can do an endoanal ultrasound to determine the severity of your tear and the quality of the repair, and then see if a revision is warranted (basically if another surgery is needed).

If I had an OASI should I go to pelvic floor PT?  Even if I am not having FI?

In a word, YES!! Pelvic floor PT can be incredibly effective for recovery from OASI in MANY areas of life, not just FI. I haven't discussed it much here, but OASI is also associated with issues like painful sex and even urinary incontinence too. Not to mention pelvic floor weakness since so much of the pelvic floor is torn with 3rd and 4th-degree tears. And, studies are showing that earlier referral to pelvic floor PT is better than later, even as early as 2.5 weeks postpartum. Once your wound has healed and you no longer have stitches, also please perform perineal scar massage. It can go a long way in restoring both the strength of your pelvic floor, and in healing issues like painful sex.So, if you had a 3rd or 4th-degree tear, or your friend did, PLEASE consider pelvic floor PT. It can spare you so much distress and additional symptoms as you age!

What if I am experiencing fecal incontinence that started after a vaginal childbirth, but I didn't have an OASI?  

I would still recommend you see a colorectal surgeon, just to have the specialized endoanal ultrasound to rule out any undiagnosed tears. One small 2019 study found that you are more likely to have a missed OASI if you had a delivery with forceps or vacuum, an episiotomy, and an epidural. And that these people with missed OASI had both fecal and urinary symptoms, some that didn't show up until YEARS after delivery. These ranged from fecal incontinence (remember this can be anything from the loss of solid stool, to liquid stool, to just staining in your underwear), flatal incontinence (unable to control the passage of gas), fecal urgency (you know you need to have a BM and have to go RIGHT NOW), and even urinary incontinence.

What if I have fecal incontinence that is unrelated to childbirth?

If you have ever delivered a child vaginally, then I would still recommend you see a colorectal surgeon first before we assume that your anatomy is intact. Otherwise you may be chasing symptoms and treatments that won't help, since your anal sphincter may not be working properly!If you only had C-sections or have not had children, then it's best to start with your PCP and/or a gastroentereologist (GI specialist). Of course, there are many non-pelvic floor reasons for FI! And some of these are something as "simple" as a GI bug that will resolve with antibiotics, or testing for food allergies. Or sometimes diseases such as Crohn's and ulcerative colitis can cause both fecal urgency and FI, so it can be good to see a GI specialist to rule these things out. If you've had all of the above ruled out, then definitely get yourself to a pelvic floor PT! Pelvic floor weakness can contribute to FI as well as anal sphincter weakness. A pelvic floor PT can also help you examine your bathroom habits, diet, and lots of other things that may be contributing to FI. Pelvic floor PTs can also help you figure out your diet, including increasing fiber to help bulk your stool, but seeing a dietitian can also help with diet-related FI.

If I had a vaginal delivery and ended up with an OASI, should I opt for a C-section next time?

This is a tricky subject, and definitely worth a detailed discussion with your OBGYN. The risk of a repeat OASIS with a subsequent vaginal delivery ranges from 3-10%, depending upon which studies you read. Whereas the risk of an OASI in a second delivery when there was not a OASI during the first delivery is only about 0.6-3.2%. So your risk is elevated, BUT, you also have to consider the risks of having a C-section. These include things like surgical injury to your uterus, bowels, and bladder; uterine infection; blood clots; and increased blood loss. ACOG recommends you consider a C-section in subsequent pregnancies if you: 

  • Experienced fecal incontinence after your OASI repair

  • Had complications such as wound infection, or a need for a repeat surgical repair

  • Experienced psychological trauma as a result of the tear & repair, and would prefer a C-section the second time around

References (many are open access!):

André, K., Stuart, A., & Källén, K. (2022). Obstetric anal sphincter injuries-Maternal, fetal and sociodemographic risk factors: A retrospective register-based study. Acta obstetricia et gynecologica Scandinavica, 101(11), 1262–1268.

Committee on Practice Bulletins-Obstetrics (2018). ACOG Practice Bulletin No. 198: Prevention and Management of Obstetric Lacerations at Vaginal Delivery. Obstetrics and gynecology, 132(3), e87–e102.

Harvey, M. A., Pierce, M., Alter, J. E., Chou, Q., Diamond, P., Epp, A., Geoffrion, R., Harvey, M. A., Larochelle, A., Maslow, K., Neustaedter, G., Pascali, D., Pierce, M., Schulz, J., Wilkie, D., Sultan, A., Thakar, R., & Society of Obstetricians and Gynaecologists of Canada (2015). Obstetrical Anal Sphincter Injuries (OASIS): Prevention, Recognition, and Repair. Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC, 37(12), 1131–1148.

Huber, M., Larsson, C., Harrysson, M., Strigård, K., Lehmann, J. P., Nordin, P., & Tunón, K. (2023). Use of endoanal ultrasound in detecting obstetric anal sphincter injury immediately after birth. Acta obstetricia et gynecologica Scandinavica, 102(3), 389–395.

Jordan, P. A., Naidu, M., Thakar, R., & Sultan, A. H. (2018). Effect of subsequent vaginal delivery on bowel symptoms and anorectal function in women who sustained a previous obstetric anal sphincter injury. International urogynecology journal, 29(11), 1579–1588.

Jurczuk, M., Bidwell, P., Gurol-Urganci, I., van der Meulen, J., Sevdalis, N., Silverton, L., & Thakar, R. (2021). The OASI care bundle quality improvement project: lessons learned and future direction. International urogynecology journal, 32(7), 1989–1995.

Klokk, R., Bakken, K. S., Markestad, T., & Holten-Andersen, M. N. (2022). Modifiable and non-modifiable risk factors for obstetric anal sphincter injury in a Norwegian Region: a case-control study. BMC pregnancy and childbirth, 22(1), 277.

Lua-Mailland, L. L., Yao, M., Wallace, S. L., & Propst, K. (2023). The Impact of Pelvic Floor Physical Therapy on Bladder and Bowel Function After Obstetric Anal Sphincter Injury. Urogynecology (Philadelphia, Pa.), 29(2), 234–243.

Marcellier, G., Dupont, A., Bourgeois-Moine, A., Le Tohic, A., De Carne-Carnavalet, C., Poujade, O., Girard, G., Benbara, A., Mandelbrot, L., & Abramowitz, L. (2023). Risk Factors for Anal Continence Impairment Following a Second Delivery after a First Traumatic Delivery: A Prospective Cohort Study. Journal of clinical medicine, 12(4), 1531.

Serati, M., Ruffolo, A. F., Scancarello, C., Braga, A., Salvatore, S., & Ghezzi, F. (2023). When does oasis cause de novo pelvic floor dysfunction? role of the surgeon's skills. International urogynecology journal, 34(2), 493–498.

Photo by Carlos Santiago: