Do Cesareans Cause Endometriosis? The Data Accumulate

 Today on Science & Sensibility, regular contributor Henci Goer takes a look at a new retrospective study looking at the potential relationship between cesarean birth and endometriosis development in the mother in the years after her surgery.  Did you know that research indicates an increase in endometriosis for those women who have undergone a cesarean delivery?  Henci shares this new study and asks us to continue to look further. – Sharon Muza, Community Manager, Science & Sensibility.


© Patti Ramos Photography

My very first post in Science & Sensibility back in 2009 was a round-up of case studies and series reporting on the formation of endometriosis—also called “endometrioma” because the cells formed a solid mass—in the cesarean wound. I commented that case studies could serve to draw attention to possible serious complications worthy of further investigation and ended the post with the hope that researchers would take a closer look at this one. Now I have run across a study that does exactly that.  I wanted to share it with you today.

Swedish investigators, Andolf, Thorsell, and Kallen (2010), used a national in-patient data registry linked to a birth registry to identify all women giving birth to their first child between 1986 and 2004. After excluding women who had a diagnosis of endometriosis before their first birth, 709,090 women remained, of whom 3110 were diagnosed with endometriosis and treated in hospitals after their first birth. Investigators tracked women from the date they gave birth to their first child to either the date of the first diagnosis of endometriosis, the date of their 55th birthday, or December 31, 2004, the date on which investigators retrieved the dataset, whichever came first.

Investigators looked both at cesarean-scar endometrioma and general pelvic endometriosis. They postulated that since endometriosis results from uterine lining cells taking hold and growing outside of the uterus, cesarean surgery could disperse these cells throughout the pelvis, not just seed them into the uterine wound.

After accounting for factors that were associated both with endometriosis and cesarean delivery (maternal age at first delivery; BMI; smoking; and years of involuntary childlessness before first delivery), none of which had any appreciable effect, they found that having at least one cesarean nearly doubled the risk of developing endometriosis (hazard ratio: 1.8). This calculated to 1 additional case of endometriosis within 10 years for every 325 women undergoing cesarean surgery. Having multiple cesareans didn’t appear to further increase the risk. Both women with only vaginal births and women with cesareans had new diagnoses of endometriosis, but a graph of the cumulative incidence rates showed that the line angled upward much more steeply as time passed in women with cesareans compared with women with only vaginal births.

The incidence rate of cesarean-scar endometrioma specifically was 1 per 1000 among women having cesareans. This may be considered a minimum since the data registry would not capture women who had cesarean-scar endometrioma but who either never received the correct diagnosis or were never admitted to a hospital for treatment.

The Swedish analysis has added to our knowledge of the relationship between cesarean surgery and endometriosis. It gave us an incidence rate for cesarean-scar endometrioma and showed that cesarean surgery also is associated with increased likelihood of developing generalized pelvic endometriosis of sufficient severity to require in-hospital treatment.  Preventing that primary cesarean can play a critical role in reducing the number of women who will deal with the pain, complications and need for treatment of endometriosis that resulted from their cesarean surgery.  When considering cesarean surgery, women should be told of the excess risk of developing generalized pelvic endometriosis and cesarean-scar endometrioma and their consequent complications (pain, irregular bleeding, infertility) as part of the informed decision-making process.


Did you know that an increase in endometriosis rates is a possible consequence of cesarean section? Are the women you are teaching and  working with aware of this potential development and what it might mean?  Do you consider this something that you would share in your role as Doula? Childbirth Educator? Midwife? OB?  Let us know in the comments. – SM


Andolf, E., Thorsell, M., & Kallen, K. (2013). Caesarean section and risk for endometriosis: a prospective cohort study of Swedish registries. BJOG. doi: 10.1111/1471-0528.12236


Cesarean Birth, Childbirth Education, Guest Posts, informed Consent, Maternity Care, Medical Interventions, New Research, Research, Uncategorized , , , , , , ,

  1. avatar
    | #1

    I had a 2×3 cm scar endometrioma removed 6 days ago and am home recovering. The pain began 11 months ago. Initially my PCP denied being able to feel the lump and diagnosed me with constipation. After 2 months of laxatives (no fun) I went back and he sent me for a pelvic ultrasound. They used intravaginal ultrasound and although I could clearly feel the mass myself, they said there was nothing there. After another month with no relief, doc sent me for a CT scan which apparently didn’t scan at the appropriate level to see the mass which was right under the skin or the radiologist missed it. After another month with more pain, went for another vaginal ultrasound which was again apparently “normal”. At this point the doc said he was stumped and sent me to my OBGYN. She was able to palate the mass and she believed the likely reason was incisional hernia but mentioned endometrioma as a small and unlikely possibility. So, off to the general surgeon! He thought hernia was possible but as I had been having some bowel irregularities he wanted a CT scan as well as a colonoscopy. After both lovely tests, my colon was apparently “normal” (although I’m not sure I trust that result in general anymore) and my CT scan showed a 4.5 cm cyst on my ovary as well as a 2×2 cm “soft tissue mass” which the radiologist hypothesized could be suture granuloma. OBGYN wasn’t worried about the cyst and I have a history of cysts so that had been left alone for now. The general surgeon decided to remove the mass and run pathology. I did have two more surface ultrasounds on the area and this ultrasound technician found it no problem twice. A month before surgery I felt another lump on the right side which the surgeon couldn’t palpate but he did find it when operating and removed it as well. Pathogy results came back yesterday and the original mass was an endometrioma and the smaller one was a lipoma. I have three inch incisions on each side of my pelvis and a bruise the size of a hot dog bun on my lower abdomen from where the endometrioma was removed. I’m 29, have a history of csection 6 years and 4 years ago. No intrapelvic endometriosis detected. Needless to say, yes, one “little” endometrioma has caused me nearly a year of pain, several missed days of work for doctors visits and now surgical recovery, exposure to 2 CT scans, 4 ultrasounds, one
    X-ray, and a colonoscopy followed finally by surgical intervention. So, although endometriomas may seem “rare” and insignificant, I assure you that they are not insignificant to those who have them occur. Pain and anxiety from an “unknown abdominal mass” is highly unpleasant. Thank goodness I have good insurance, a forgiving work schedule, a supportive spouse, and available medical care. I could not imagine going through the last 11 months as a single mom with no insurance. And, no, endometrioma was never discussed as a possible side effect of a csection. In fact, my first OBGYN encouraged me to have a csection 9 days before my due date because “the baby is going to be 9 pounds and its your first baby and you will probably have to have one anyway”. Being 23, hot and miserable in July in the south, and trusting my doctor, I had a csection as advised without any attempt to induce labor. I never had one contraction. Oh, and my baby was 7lbs. Hope this helps raise awareness of this unpleasant possible complication of csections, especially potentially unnecessary csections.

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    Jenny, this is a heartbreaking story! best wishes to you as you recover. Thank you for sharing.

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    I am sorry for your nightmare experience. I sympathize with your frustration and hope that you have now made a speedy and complete recovery. Personally, I think there are far more cases of cesarean-scar endometrioma and cesarean-related general endometriosis than the research literature suggests because the only cases we know about are the ones in women admitted to the hospital for treatment. I suspect these cases may be the tip of the iceberg and that many more women either never seek treatment for their symptoms or give up when they are told there is nothing wrong with them or decide they would rather live with their symptoms than undergo surgery.

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    | #4

    I have had three csections and a lumbar lamnectomy and disectomy. The pain before my period is debilitating to the point I cry every time I stand up and move any certain way other than laying on my side it is verry similar to my bulging disk pain but worse…i have radiating all the way down my legs and pressure that wraps all the way around my pelvis..lower back spasms and a burning tingling and numb like feeling in my hips and down my legs. I cant poop and pee only hapens if Im standing up. Doctors dont see any thing other than my back injuries and cant explain to me why i have these episides before my periods and why they go away after..sex is allways painful internally like something has hit me in my uterus. My csection scar will swell up on one spot and become verry sensitive ..exausted !! Any one have thoughts on what this might be please respond. I want my life back -k-

  5. avatar
    | #5

    I had almost a year of pain until I knew what it was. I started noticing a burning pain on one side of my c section scar December of 2013. My son was 2 years and 4 months old. I would push in on my scar and sometimes feel a large lump. Primary doctor said it was a hernia, went to see a hernia surgeon and got a cat scan , no hernia’s was seen just a lot of scar tissue on that side. My OB Gyn thought i had a muscle injury and I was sent to Physical therapy and massage therapy , the second time the massage therapist deeply massaged my scar the next day I was in horrible pain it lasted for 6 days , even standing and walking was sore and i was crying to everyone and yelling at the medical staff. I was upset at not getting a straight up answer. I told the doctors I was not getting any more massages and demanded another cat scan which they would’nt do. The surgeon felt sorry for me with my strange pain and two boys age 3 and age 8 and offered to do surgery to remove the built up scar tissue whenever i could do it. After learning that he does lots of more complicated surgeries on hernias and stomachs etc I agreed to do it my lump was felt under the skin so I figured 5-7 days recovery and I would be fine. Last month I did it, I was sore for about 48 hours , got 4 staples on my same C section scar , felt immediate relief no burning or pinching. It turned out to be 2 inches of endometrial tissue growing in my incision. I was shocked, never heard of this happening. I really hop it does not grow back and I would’nt wish that pain on anyone who had a c section.

  6. avatar
    | #6

    The Swedish study has one important weakness that they should have mentioned in the full study’s discussion: the entire study is based on the retrograde theory, i.e. “the uterine lining cells taking hold and growing outside of the uterus” which then would cause endometriosis. However, we know today that this is most likely not true: the cells in the uterus are not identical to the endometriosis cells, and they most probably do not travel to the pelvic cavity in such a way that they would develop into endometriosis. Even men can have endometriosis and they obviously do not have a uterus and those cells. The cells of endometriosis are different and the mechanism of the illness is likely caused by something else (e.g. one plausible theory suggests it possibly starts at the embryonic stage when cells divide and specialise). While other aspects of the Swedish study are interesting and mind stimulating, the authors should have acknowledge this fundamental weakness in their paper.

  7. avatar
    | #7

    I too had a c-section and a few years later I felt a bump in that area in the c- section. The only way for me to describe the pain is a lot of cramping but oddly you can feel the symptoms in that area. I can always tell when I’m getting my period as I can feel it in that area. I did have surgery to have it removed and it has gotten better but I know it is not gone. That surgery was about 10 years ago. If seems like it is not completely gone as I can still feel that weirdness in that general area. I never had issues before and I know it was from my emergency c- section.

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