Women who experience frequent miscarriages or stillbirths are at a higher risk of future stroke, according to pooled analysis of eight studies published in the BMJ.1

In this study, researchers examined data from 618,851 women aged 32-73 years from eight prospective cohort studies from seven countries namely Japan, Australia, China, Sweden, UK, Netherlands and the US who were a part of the InterLACE (International Collaboration for a Life Course Approach to Reproductive Health and Chronic Disease Events) consortium. They aimed to investigate a possible link between infertility, recurrent miscarriages/stillbirths with the risk of first non-fatal and fatal stroke. The selected study subjects had experienced non-fatal or fatal stroke and had data for infertility, miscarriage, or stillbirth. Self-reported questionnaires were used to identify non-fatal strokes, while data obtained from the death registry aided identification of fatal strokes. The hazard ratios were adjusted for race/ethnicity, body mass index, smoking status, education level and hypertension.

Pooled analysis of data showed that 9265 (2.8%) women experienced a first non-fatal stroke, while less than one percent i.e., 4003 women suffered a fatal stroke. Among the study subjects, 17.2% experienced infertility, 16.6% reported miscarriage/s, while 4.6% had a stillbirth.

The risk of non-fatal stroke was higher in women with infertility with a hazard ratio of 1.14. The risk of stroke was also found to be higher in women with history of minimum of three abortions with hazard ratio of 1.35 for non-fatal stroke and 1.82 for fatal stroke. Similarly, stillbirths also correlated with stroke risk. The risk of non-fatal stroke was 31% higher (HR (1.31), while the risk of fatal stroke was increased by 26% (HR (1.26).

The non-fatal stroke type in women with infertility or stillbirths was mainly ischemic stroke (HR 1.15), whereas both ischemic and hemorrhagic stroke subtypes were prevalent among women with recurrent miscarriages (HR 1.37 and HR 1.41, respectively). Ischemic and hemorrhagic subtypes of fatal stroke were common in the participants with history of recurrent abortions (HR 1.83 and HR 1.84, respectively). Among women with multiple stillbirths, hemorrhagic stroke was more prevalent (HR 1.44).

Based on these findings, the authors suggest history of recurrent stillbirths or abortions as a risk factor for stroke and highlight the need to carefully monitor such women to preempt a stroke, which can be potentially life-threatening.

Reference

1. Liang C, et al. Infertility, recurrent pregnancy loss, and risk of stroke: pooled analysis of individual patient data of 618 851 women. BMJ. 2022 Jun 22;377:e070603. doi: 10.1136/bmj-2022-070603.