Postpartum stroke risk increased after fertility treatment

The risk of having a stroke in the first year after giving birth is higher in people who had fertility treatment compared to those who conceived naturally.

Researchers at Rutgers Medical School in New Jersey found that compared to individuals who conceived naturally, patients who had IVF, ICSI, intrauterine insemination, or used frozen gametes were at a 66 percent increased risk of being hospitalised with a non-fatal stroke.

'Strikingly, the increase in risk was evident even as early as the first 30 days post-delivery,' wrote the authors of the study, which was published in JAMA Network. 'Which highlights the need for early and continued follow-up in this population.'

The study looked at records from 31 million pregnancies in people aged between 15-54 years, who gave birth between 2010 and 2018, and were hospitalised within 12 months of delivery.

They found that the risk of haemorrhagic stroke (bleeding in the brain) was more than doubled, whereas risk of ischemic stroke (loss of blood supply to the brain) increased by roughly 50 percent. They found that the postpartum stroke risk increased over time.

The study authors proposed three theories explaining the observed association between increased risk of stroke hospitalisation and fertility treatment. First: some complications known to be associated with fertility treatment, such as pre-eclampsia, raise blood pressure, which in turn could increase stroke risk. Second, that infertility treatment itself may also also increase risk:

'Patients often receive large amounts of oestrogen, for example, which can lead to increased blood clotting, a strong risk factor for stroke,' senior author Dr Cande Ananth, chief of epidemiology and biostatistics at Rutgers Medical School, told the New York Times.

Third, the authors accept that people with infertility (especially unexplained infertility) may already have certain predisposing health factors including obesity or diabetes.

This study, which used data from the US Nationwide Readmissions Database, is believed to be the largest study to date assessing postpartum risk of stroke hospitalisation.

Although stroke accounts for around seven percent of pregnancy-related deaths in the USA, absolute risk of hospitalisation for stroke after pregnancy remains low.

'In general, fertility treatments are very safe, and most patients tolerate it well,' said reproductive endocrinologist Dr Alex Robles from Columbia University in New York, who was not involved with the study. 'However, it is important to get a thorough consultation … to evaluate your risk and candidacy to undergo such treatments.'