Infertility and pregnancy loss may increase stroke risk in women later in life

Infertility and pregnancy loss are associated with an increased risk of nonfatal and fatal stroke later in life, according to an analysis of observational studies, published in The BMJ.

Early follow-up of women who have experienced miscarriage or stillbirth, along with healthy lifestyle changes, may reduce the risk of stroke, the researchers suggest.

Globally, strokes are one of the leading causes of death and disability among women. In 2019, approximately 3 million women died from stroke. Additionally, women lost a total of 10 million years of healthy life due to disability following stroke, 44% more years than men.

Known stroke risks such as obesity, high blood pressure and diabetes do not fully explain the higher risk of stroke in women. Previous studies on the link between infertility, miscarriage, and stillbirth with long-term stroke risk have been inconclusive.

To fill in the gaps, this study aimed to assess the link between infertility, miscarriage and stillbirth with risk of fatal and non-fatal injury.fatal strokeand specific type of stroke.

The researchers analyzed Data from the InterLACE consortium, which brings together data on reproductive health and chronic diseases, out of a total of 27 studies. Data from eight studies from seven countries (Australia, China, Japan, Netherlands, Sweden, UK and USA) were included in the analysis.

Questionnaires were used to find information on infertility, miscarriages and stillbirths. Data on nonfatal strokes were also found using self-reported questionnaires or hospital records. Hospital data were used to identify fatal stroke cases and stroke subtypes (haemorrhagic or ischemic).

In total, approximately 620,000 women were included in the study, aged 32 to 73 at baseline.

Of these, 275,863 women had data on nonfatal and fatal strokes, 54,716 women only had data on nonfatal strokes, and 288,272 had data only on fatal strokes. Of these, 9,265 (2.8%) women had a first non-fatal stroke at a median age of 62 years, and 4,003 (0.7%) had a fatal stroke at a median age of 71 years. .

Women with a non-fatal stroke before age 40 were excluded, as they may have had a stroke before a history of infertility, pregnancy loss or stillbirth could be established. Several factors that could have influenced the results were also taken into account, such as ethnicity, weight, lifestyle and underlying conditions.

Infertility, miscarriages and stillbirths were all associated with an increased risk of stroke, especially recurrent (three or more) miscarriages and stillbirths, according to the study.

Women with a history of infertility had a 14% higher risk of non-fatal stroke than women without infertility.

Miscarriage was also associated with an 11% higher risk of non-fatal stroke compared to women who had not had a miscarriage. The risk increased with the number of miscarriages a woman had: one, two and three miscarriages led to a 7%, 12% and 35% increase in stroke risk, respectively.

For women who had three or more miscarriages, the increased risk of non-fatal ischemic and hemorrhagic stroke was 37% and 41% respectively. Similarly, for fatal ischemic and hemorrhagic strokes, three or more miscarriages were associated with an increased risk of 83% and 84% respectively.

A history of stillbirth was associated with a 30% higher risk of nonfatal stroke, and women who had multiple stillbirths (two or more) were almost 80% more likely to have a nonfatal ischemic stroke.

The study also found that recurrent stillbirth was associated with a more than 40% higher risk of fatal stroke.

Researchers say the link between infertility and increased risk of stroke may be due to conditions such as polycystic ovary syndrome (PCOS) and premature ovarian failure (POI), while endothelial dysfunction (narrowing of the heart’s blood vessels) may explain the increased risk of stroke in women with a history of stillbirth or recurrent miscarriage.

But they also suggest that unhealthy lifestyles (such as smoking or obesity) are also associated with pregnancy loss, as well as infertility, which could also contribute to an elevated risk of stroke. cerebral.

This is an observational study and as such cannot establish causation. The study has other limitations, for example, the information was collected from questionnaires; the effects of other treatments have not been explored due to limited data; and definitions of infertility, stillbirthand miscarriages may differ from study to study.

Nevertheless, this was a large, well-designed study and the results remained largely unchanged after further analyses, suggesting that the results are robust.

According to the researchers, “having a history of recurrent pregnancy loss may be considered a female-specific risk factor for stroke.”

And they suggest early monitoring of women with a story of pregnancy loss Where infertility while promoting healthy habits can help reduce their risk of stroke later in life.