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. 

The Pill, lean muscle development & fertility awareness: could contraception be impairing your gains?

Muscle mass growth and the Pill: could contraception be impairing your gains?

It’s no secret that hormonal contraception can impact the body in a variety of ways. While some women may experience positive impacts from birth control, others are left with less than desirable side effects.

If you’re on the pill or another form of hormonal birth control, did you know that it could be negatively impacting your muscle growth?

That’s right, your contraception could be impairing your gains!

The Pill and muscle gains

The Pill may affect your muscle gains by affecting fat metabolism. It’s been shown that the Pill can alter energy levels, and this can slow down fat-burning. An insulin-like growth factor (IGF-1) is known to help build muscle, but the Pill can lower its production, as well as lowering estrogen and testosterone production. What’s more, the Pill can also interfere with growth hormone release—one of its main functions is to stimulate muscle growth. All of these factors combined means that the Pill could potentially have a negative impact on your muscle mass development.

The Pill, training and fitness

The Pill is no stranger to controversy. For example, there’s the long-standing speculation that hormones in birth control could lead to weight gain (which we’ve debunked with science). But one of the most common complaints you’ll hear from women who use oral contraception is that they notice a dip in strength, muscle mass, and general fitness levels after starting the pill.

While it can be difficult to separate out the effects of birth control from all the other factors that influence your training—like diet, stress and sleep—we wanted to find out if there’s any truth to this particular claim. We looked at the evidence to find out what kind of impact hormonal contraceptives can have on your fitness levels and how you might be able to minimise them.

If you’re serious about building muscle, some forms of hormonal birth control could be holding you back.

If you’re a female athlete, training with weights can be a crucial part of your fitness routine. Strength training is essential for building muscle mass and optimising your metabolism. Women need to maintain muscle mass as they age to avoid osteoporosis, frailty, and sarcopenia (loss of muscle mass). The ability to build muscle also declines as we age.

Interestingly a study released last year demonstrated the impact of hormonal contraception on lean muscle mass might be more profound than we have previously realised. It compared two groups of women both on and off hormonal contraception over a 10 week strength building program. The women that were taking hormonal contraception had significantly lower lean muscle mass gains, and higher levels of cortisol (the stress hormone), as well as lower levels of IGF-1.

The reason for the impairment of muscle growth appears to be related to the Pill impairing the anabolic and catabolic hormones that regulate muscle development, and possibly the effects of synthetic progestin on androgen receptors.

“Oral contraceptive use impaired lean mass gains in young women after RET and was associated with lower DHEA, DHEAS, and IGF-1 and higher cortisol”

Reichmann & Lee, 2021

The pill or other hormonal contraceptives may not be suitable for all women who want to build lean body mass or get serious about their fitness. The first step is to evaluate your goals and what you are hoping to achieve with exercise and proper nutrition while taking oral contraception or other types of hormonal birth control. Some forms of contraception could affect gains if you have specific fitness or health goals.

Natural birth control

If you’re concerned with how your birth control may be affecting your muscle mass, it’s important to understand the benefits of non-hormonal contraception. These are methods of avoiding pregnancy that don’t require a prescription or implantation, and they can help you understand and embrace your cycle with no side effects. To begin with, there are two primary types of natural birth control: barrier methods, which prevent sperm from entering the woman’s body (such as condoms), and fertility awareness-based methods, which involve tracking fertile biomarkers and ovulation, so that you know when not to have sex, or to use a barrier method.

These options may seem less convenient than popping a pill or having an IUD implanted in your uterus, but for those who want more control over their hormonal health without any added chemicals like estrogen and progestin from synthetic HBCs, these options may be empowering.

To learn more about the Symptothermal Method of Fertility awareness for contraception, check out our free resources or our comprehensive course Contraception: Naturally.


  • Riechman SE, Lee CW. Oral Contraceptive Use Impairs Muscle Gains in Young Women. J Strength Cond Res. 2021 May 14. doi: 10.1519/JSC.0000000000004059. Epub ahead of print. PMID: 33993156.

Olaplex, infertility & what it really tells us about choosing beauty products

Unpacking the truth about lilial & the EU Scientific Committee for Consumer Safety…

After watching a broad spectrum of reporting (and TikTok videos) on the topic of infertility and Olaplex, I felt that I had to weigh in. Maybe you’ve seen the articles, TikToks and Instagram stories about Olaplex and infertility, with influencers throwing away costly product and swearing off it. 

What is the drama? What is the science? And should YOU be worried? 

Very simply, Olaplex No. 3, the at-home hair repair ‘miracle’ product, has been flagged for containing butylphenyl methylpropional – more commonly known as lilial in it. It was also present in their No. 1 & No. 2 products. Was? More on that in a moment.

First, let me explain what lilial is. It’s role in cosmetics and beauty products is as a sweet smelling fragrance – many describe it as “Lily of the Valley” in terms of smell. You would probably be surprised how many products contain it. For example, a simple search for butylphenyl methylpropional on Sephora’s offerings returns 143 results – but this is just the products that disclose this component within their ingredient list. Fragrance or parfum components in cosmetics, and other beauty products, are often considered to be trade secrets – by both the Australian Competition and Consumer Commission and the FDA in the US, which means that unless explicity requested, companies do not have to disclose the components of their fragrances on the label – they can simply label “fragrance” “parfum” or similar. 

“Fragrance and flavor formulas are complex mixtures of many different natural and synthetic chemical ingredients, and they are the kinds of cosmetic components that are most likely to be “trade secrets.””

FDA, Fragrance in Cosmetics, 2022

So why is the EU Scientific Comittee on Consumer Safety (SCCS) concerned? 

Back in 2019, the committee made a recommendation that lilial (by all its different names) be phased out of cosmetic and personal care products – due to its concerns about the potential for reprotoxic effects. 

Essentially, at certain concentrations, lilial was demonstrated to have negative effects on both the male and female reproductive systems – particularly on eggs and sperm – and also to have impacts on development during pregnancy. It also stated that the safety data around gene mutation and chromosomal damage was not conclusive. 

However, here are some things to remember: the safety data is based on:

  1. Animal studies *trigger warning*
  2. Using 15 beauty products containing lilial and still only getting 1/80th of the safety limit in a day

By comparison: the amount contained in a perfume is 70 times higher than in a hair product – and it is aerosolized, increasing your absorption through your lungs.

“On individual product basis, Butylphenyl methylpropional (p-BMHCA) (CAS 80-54-6) with alpha-tocopherol at 200 ppm, can be considered safe when used as fragrance ingredient in different cosmetic leave-on and rinse-off type products. However, considering the first-tier deterministic aggregate exposure, arising from the use of different product types together, Butylphenyl methylpropional at the proposed concentrations cannot be considered as safe.”

EU Scientific Committee on Consumer Safety, OPINION ON
the safety of Butylphenyl methylpropional (p-BMHCA) in cosmetic products
– Submission II –
, 2019.

So while there was the potential for toxic effects on reproduction – the decision of the committee was primarily put in place to prevent potential harm – there has been no documented cases of lilal causing human infertility. But this approach to phasing out ingredients with potential adverse effects is a positive step – because it is encouraging companies to be proactive in removing them from their manufacturing. 

The reason these findings are being focussed on now is because in the EU and Northern Ireland there was a 1 March deadline to remove this component from all personal care products – although they can continue to be used in household cleaners, detergents and laundry powders.

Wait, so why did you say WAS present?

The good news is that this finding MAY be the start of a cascade of change in the cosmetic industry. As I already mentioned, lilial is not the only product that has potential reprotoxic effects – a unknown number of them do. 

Olaplex has proactively removed this component from their products since the start of 2022 – ahead of the 1 March regulatory guideline – and has done it not just in the EU and Northern Ireland – but globally – even though there was no requirement for them to do so. Before you throw out your Olaplex product, or change hairdressers, just check the back of the ingredient list to determine whether this is the updated formulation excluding lilial. And the amounts that were contained in the original formulation were not at a level that was likely to cause harm to your fertility or unborn child – infertility is not likely to have been directly caused by Olaplex.

Another positive note about Olaplex is that while they did have products contained lilial – they have always excluded a variety of other significant endocrine disrupting chemicals including phthalates, parabens, formaldehyde and formaldehyde-releasing chemicals. So compared to many other products on the market, they have made mindful steps in their manufacturing to move away from many harmful chemicals that are common in the beauty industry. 

One of the biggest places that endocrine disrupting chemicals hide in the beauty industry is in the fragrance component – because they do not have to disclose these components under trade secret protections. So how can you avoid them? 

  1. By making a switch to a fragrance free product  or one with a  natural fragrance component (make sure they disclose their whole ingredient list for this).
  2. Request an ingredient disclosure for the fragrance component if you have a product you can’t live without – you can then research the components on the Environmental Working Group’s SkinDeep list.
  3. Lobby your favourite companies to make a change: for your health, our childrens’ health and the health of the environment. If they won’t – walk away with your dollars.

You don’t have to do this all at once, and you don’t have to do it at all! But if you want ONE place to start: you are better off switching or ditching your spray perfume, these are more likely to have impacts than your hair care products. 

We can contribute to change – by switching to products that do not include artificial fragrances, by mindfully supporting brands that are making manufacturing changes and by lobbying our favourite companies to make the transition to a hormone-healthy formulation and away from chemicals that are making negative impacts on our health and the health of future generations. 

Don’t cancel Olaplex: they are getting so many things right.

Say it with me: it’s all about informed choices.

You can read the full opinion from the EU Scientific Committee on Consumer Safety here *trigger warning* extensive reference to animal testing in this document

You can view Olaplex’s explanation and Q&A on lilial and the changes they’ve made here