Having a baby after PCOS and endometriosis: A complex fertility journey

Caitríona O’Donnell has endometriosis and polycystic ovary syndrome and knew she would need help to get pregnant. A new treatment targeting an overactive immune system ultimately led to the birth of her baby

Caitriona O’Donnell and her daughter at home in  Limerick city. Picture: Brendan Gleeson

IT was a hard year in 2024 for Caitríona O’Donnell. She and her husband, Ruairí, began to lose hope that they would ever have a baby.

“We’d been childhood sweethearts since our Leaving Cert year,” says the 34-year-old occupational therapist from Limerick. “We got engaged in 2018 and started trying for a baby in 2019, when we were both 27. We never thought we’d have such a long journey ahead of us. After years of struggling to conceive and two IVF cycles that either failed or ended in miscarriage, by 2024, our hopes were fading.”

Yet, in October 2025, O’Donnell gave birth to a daughter. She credits immunology testing, an emerging branch of fertility treatment, for the happy outcome.

“My situation was so complicated,” O’Donnell says. “It started when I came off the contraceptive pill and immediately started gaining weight, getting acne, having mood swings, and feeling exhausted. Within months, my GP diagnosed polycystic ovary syndrome (PCOS). The pill had masked its symptoms.”

PCOS can affect fertility, and as time went by and the couple failed to conceive, tests were carried out to check their reproductive systems. “Everything looked normal, and I was ovulating regularly,” says O’Donnell. 

“All of Rory’s tests showed there were no problems on his side. So, in 2022, I had investigative surgery to find out if there were underlying issues with me, which found stage-four endometriosis. I’d been entirely asymptomatic.”

Endometriosis is a condition in which tissue similar to the lining of the uterus grows outside the uterus, causing inflammation, scar tissue, or adhesions. Like PCOS, it can also impact fertility.

The O’Donnells decided their best option was IVF. They did their first cycle in February 2023. It resulted in a positive pregnancy test, but ended in miscarriage. A second cycle, in October 2023, resulted in one failed implantation, followed by another miscarriage.

In June 2024, O’Donnell decided it was time for a different approach. She says she felt her situation was “so complicated that it didn’t fit the standard IVF treatment model. I needed more testing and support.”

Immune system

O’Donnell visited online fertility forums, where Dr Lyuda Shkrobot was often mentioned. “Dr Shkrobot is a gynaecologist and fertility specialist at UNQLife Clinic in Dublin,” she says. “I felt in my gut that the services she has to offer could be good for us.”

Shkrobot is scheduled to speak about those services at the Future Fertility Show in Dublin’s RDS on March 21 and 22. The main topic will be how women’s immune systems can resist their attempts to have a baby.

Shkrobot says that the human “immune system has evolved to destroy foreign bodies. It gets rid of bacteria, bugs, and viruses that don’t share our DNA”.

An embryo or foetus only shares 50% of its DNA with its mother. “The other 50% comes from the male side,” says Shkrobot. “In mothers with normally balanced immune systems, this is not a problem.

“Their bodies release protective antibodies that stop the immune system from rejecting the pregnancy and help maintain it until delivery.”

But the immune system of women who have endometriosis or conditions like Crohn’s disease, rheumatoid arthritis, or diabetes may not be balanced. Shkrobot says they can be “in inflammatory mode, which causes the body to release fewer antibodies and more natural killer cells. These are specialised white blood cells. In normal quantities, they help the immune system adapt to pregnancy. But when elevated, they can fight the pregnancy.”

O’Donnell’s IVF clinic suggested she do the Chicago blood test. Costing up to €1,100, it checks natural killer-cell levels in a woman’s blood, as well as her level of cytokines, which are proteins that trigger immune responses, such as inflammation.

“With the Chicago test results, we can see whether the immune system is pro- or anti-inflammatory and take steps to balance it,” says Shkrobot. “We can also take a uterine biopsy to check how many uterine natural killer cells are in the uterus and treat the patient accordingly.”

The science behind the Chicago blood test and the role of natural killer cells in recurrent miscarriage is still emerging, and some doctors remain sceptical.

However, a 2020 Spanish study suggested that natural killer cells were more active in women with recurrent miscarriages and also found that these women had a higher level of pro-inflammatory cytokines. 

An international study published last year found that abnormal uterine natural killer cells and cytokine production were linked to pregnancy loss.

Embryo transfer

When O’Donnell got the results of her Chicago blood test, they showed that both her natural killer-cell and cytokine levels were high.

“I wasn’t surprised, considering my diagnosis with PCOS, endometriosis, and a more recent autoimmune skin condition,” she says

Shkrobot used O’Donnell’s test results as a basis to prescribe a personalised protocol of immune-modulating medications and treatments to bring down her levels of natural killer cells and cytokines before her next embryo transfer.

That embryo transfer resulted in pregnancy, and O’Donnell decided to continue seeing Shkrobot during her first trimester. She availed of UNQLife’s Early Pregnancy Care Support programme, which involves taking twice-weekly blood tests and following a personalised course of treatment and medication based on the test results.

According to the HSE, one in six couples in Ireland experiences fertility issues, and 20% to 30% of those will be diagnosed with unexplained infertility. This means that no specific cause is found after standard testing.

Shkrobot believes immune issues could explain some of these cases.

“The patients who come to us have normally had failed cycles elsewhere and no answer as to why their embryos didn’t implant or their pregnancy was lost,” she says.

Often, they are told to come back for another IVF cycle, and little is done to investigate the reason for their previous failure.

Instead of simply trying again, Shkrobot urges “anyone who has experienced recurrent miscarriages”, particularly those with a family history of inflammatory conditions, to get their blood tested for markers of inflammation.

She says GPs can carry out CRP, ESR, and Il-6 blood tests to measure systemic inflammation and that further testing can be carried out if those tests detect a problem.

“If your pregnancy loss is related to inflammation or problems with your immune system, there are treatments like steroids that can help,” she says.

O’Donnell believes immunology testing and treatment are what allowed her and Ruairí to have their much-longed-for daughter.

“I would urge anyone with complex fertility problems to look into immune support,” she says.

“Ruairí and I are fortunate to have embryos in storage, and if we try for another baby, I’ll definitely be getting immune support again.”