Caesarean Scar Isthmocele and Secondary Infertility – are we talking about this enough? 

April is Caesarean-Section Awareness Month. In 2020, 1 in 3 babies globally was delivered by C-section, and for many a C-section delivery is a life saving procedure for mother, child, or both [1]. 

I wanted to take this opportunity to discuss one increasing trend that we have seen emerge around secondary subfertility and Caesarean-scar isthmocele – if you have had a C-section in the past, and are struggling to conceive now, or are suffering from unexplained pelvic pain or abnormal uterine bleeding, C-section isthmocele might be a condition to ask about.

Unfortunately, Caesarean section isthmocele is a condition that not many women are aware of, so it can take a prolonged amount of time to identify this as the cause of their symptoms.

What is Caesarean Section Isthmocele?

Uterine isthmocele was first described in 1995, however our awareness of its relevance in fertility and future pregnancy has only come into its own over the past few years – with much more extensive research necessary and indicated. 

Diagnosis of Caesarean section isthmocele, starts with the symptoms that a woman is experiencing – after excluding other causes of abnormal uterine bleeding, a transvaginal ultrasound and hysterosonography may be undertaken. Hysteroscopy may also be implemented, as it allows a clear view of the pouch itself, and may allow its correction [2]. 

An isthmocele is a reservoir-like pouch that has formed in the front wall of the uterus at the site of the Caesarean section scar. They are bigger than 1-2mm and are usually triangular in shape, although some will be semicircular [3]. 

These pouches may contain fluid or blood, sometimes small volumes of a few ml, up to >30ml. 

Usually, a woman with a Caesarean scar isthmocele will experience no symptoms, and these require no further treatment, even if incidentally noticed on ultrasound. Unless they are causing symptoms they do not require intervention [3]. 

The most common symptoms associated with Caesarean scar isthmocele are: 

1. Abnormal uterine bleeding – particularly dark post-menstrual spotting (in the absence of other causes),

2. Pelvic pain,

3. Secondary infertility [3].

Yes, you read that right. Secondary infertility on its own is a SYMPTOM of a underlying condition.

Secondary infertility is difficulty in conceiving following previous successful pregnancy and birth – whilst the specific rates of secondary infertility are difficult to pinpoint, it is beginning to be evident in Western countries that secondary infertility can be as high as 1 in 6, the same is primarily infertility.

Sub-fertility represents one of the serious, potential long-term impacts of Caesarean section [4]. Rising numbers of C-sections may lead to rising trends in secondary infertility, if we don’t push more research and comprehensive support in this area. Despite rising numbers of C-sections, there has been little progress in raising awareness around the effects that isthmocele may have on future fertility, or the importance of its investigation in presentations of secondary infertility.

Secondary infertility may be caused as the collected blood/fluid in the pouch may affect the quality of cervical mucus, making it inhospitable to sperm [5].

Persistence of menstrual blood in the much may also obstruct sperm transport through the cervical canal, interfere with embryo implantation and lead to secondary infertility [6]. 

The post-menstural spotting is usually due to the accumulation of blood in the pouch during menstruation, then being discharged subsequently [3]. 

Risk factors and prevention of caesarean section isthmocele

Whilst the complication is more common in women that have a retroverted uterus and in women with multiple C-sections, the exact mechanism is not completely understood. It is thought that the tissue may have reduced healing due to poor blood circulation in that area, however other factors such as the stage of labour of the C-section, the suturing technique and a few other surgical wound closure factors, may also play a role [7]. 

Other risk factors include: premature rupture of membranes, short operation time for the C-section and the extent of cervical dilatation at time of C-Section. The short operation time was taken to indicate that more time should be taken to ensure a careful and thorough approach to uterine closure post C-section [7].

Pregnancy complications in future pregnancies may include higher rates of ectopic pregnancy and lower implantation rates [7].

Caesarean Scar Isthmocele & ART/IVF

Even within the context of IVF, women with history of an existing isthmocele from previous c-section have increased risk of developing intracavity fluid during ovarian stimulation – in fact, this may happen in 40% of cases. Presence of this endometrial fluid has an adverse effect on implantation, reducing pregnancy success rates.  However, in cases where women with isthmocele did not develop intracavity fluid, success rates were comparable to women without isthmocele [8].


In women experiencing symptoms, including secondary infertility, treatment of the isthmocele may be necessary. 

Medical and expectant “let’s wait and see” treatment are not reflected to be effective in current research. For women wishing to conceive, or planning a future pregnancy, minimally invasive surgical correction of the isthmocele generally gives the best outcome. 

Many isthmoceles can be corrected via hysteroscopic or laparoscopic repair, with a hybrid of the two options beneficial in many cases [9]. Patient outcomes appear similar across both surgical options, with improvement of pelvic pain, abnormal bleeding and secondary infertility in significant numbers after the surgical revision [10]. 

Surgical removal of the local inflammed tissue and correction of the pouch through a minimally-invasive method can improve pelvic pain, abnormal bleeding symptoms and has been demonstrated to restore fertility in many cases [6]. 

In one very small study of hysteroscopic correction of symptomatic isthmoceles:

  • 42.8% of the participants became pregnant within 6-8 months post-surgery [2]. 
  • In another small study, 91.7% of the participants who wished to conceive did so, including 60% of those with secondary infertility. 45% of these pregnancies carried to term and had successful deliveries both via C-section and VBAC [10].  

With so many births happening via C-section, having full and frank discussion about the possibility of Caesarean Isthmocele in cases of unexplained secondary infertility can be a fruitful and viable option for many women, with minimally invasive revision a helpful option.

Charting and understanding your cycle will provide valuable additional insight into the potential for caesarean scar isthmocele, with correlation between unusual post-menstrual spotting and cyclical pelvic pain becoming clear through cycle tracking. Insight from a qualified fertility awareness educator will also help to identify and rule out any other potential barriers to conception and help you to optimise your fertility and reproductive health, irrespective of caesarean scar isthmocele. We signpost to minimally invasive surgeons in these cases also.

You can learn more about our fertility course and personalised support here: Conceiving: Naturally.

Have questions regarding this article? Or seeking personalised clinical support in this area? Please reach out to us via our contact page! We’d love to hear from you.

Reference List 

  1. Cesarean Section Awareness Month,

2. Carrillo de Albornoz, A.V., Carrasco, I.L., Pastor, N.M., Blanco, C.M., Matos, M.M., Pacheco, L.A., Bartolome, E.M. (2019). Outcomes after hysteroscopic treatment of symptomatic isthmoceles in patients with abnormal uterine bleeding and pelvic pain: a prospective case series. International Journal of Fertility and Sterility, 13(2), 108-112. 

3. Park, IY., Kim, MR., Lee, HN., Gen, Y. (2018). Risk factors for Korean women to develop an isthmocele after a cesarean section. BMC Pregnancy & Childbirth, 18(1).

4. Sandall J, Tribe RM, Avery L, Mola G, Visser GH, Homer CS, Gibbons D, Kelly NM, Kennedy HP, Kidanto H et al. (2018) Short-term and long-term effects of caesarean section on the health of women and children. The Lancet, 392:1349–1357.

5. Van der Voet, L,F., Bij de Vaste, A.M., Veersema, S., Brolmann, H.A., Huirne, J.A. (2014) Long-term complications of caesarean section. The niche in the scar: a prospective cohort study on niche prevalence and its relation to abnormal uterine bleeding. British Journal Of Gynaecology, 121 (2), 236-244. 

6. Florio, P., Filippeschi, M., Moncini, I., Marra, E., Franchini, M., Gubini, G. (2012). Hysteroscopic treatment of the cesarean-induced isthmocele in restoring infertility. Current Opinion in Obstetrics & Gynecology, 24(3), 180-186.

7. Setubal, A., Alves, J., Osorio, F., Guerra, A., Fernandes, R., Albornoz, J., Sidiroupoulou, Z. (2018) Treatment of uterine isthmocele, a pouchlike defect at the site of a cesarean section scar. Journal of Minimally Invasive Gynecology, 25(1), 38-46.

8. Lawrenz, B., Melado, L., Garrido, N, Coughlan, C., Markova, D., Fatemi, Hm. (2020). Isthmocele and ovarian stimulation for IVF: considerations for a reproductive medicine specialist. Human Reproduction, 35(1), 89-99.

9. Vervoot, A., Vissers, J., Hehenkamp, W., Brolmann, H., Huirne, J. (2018). The effect of laparoscopic resection of large niches in the uterine caesarean scar on symptoms, ultrasound findings and quality of life: a prospective cohort study. British Journal of Gynaecology, 125(3), 317-325.

10. Enderle, I.,Dion, L., Bauville, E., Moquet, PY., Leveque, J., Lavoue, V., Lous, ML., Nyangoh-Timoh, K. (2020). Surgical management of isthmocele symptom relief and fertility. European Journal of Obstetrics & Gynaecology & Reproductive Biology, 245. 

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