Health. How does long-term Covid disrupt the menstrual cycle?

Long Covid, or post-Covid-19 illness, is characterized, according to the World Health Organization, by a series of symptoms that generally appear within three months of infection.

It lasts at least two months and causes various symptoms such as fatigue, muscle pain, dyspnea, headaches, concentration problems, etc.

While long Covid affects between 3 and 7% of the world's population , with a prevalence twice as high in women as in men , various studies have shown that the disease can cause menstrual cycle disorders, even if the link between these disorders and Covid-19 was until now poorly established.

Heavy periods and worsening symptoms

To understand the mechanisms at play, a team of Franco-British researchers took up the subject. The results were published Tuesday, September 16, in the journal Nature Communications . They combed through data from a British online survey of thousands of women conducted between March and May 2021.

More than 1,000 of them had long-term Covid, 1,700 had recovered from acute infection, and 9,000 had never been infected.

The former reported heavier and longer periods. They also had more frequent bleeding between periods. While women who had recovered from a standard-length Covid case reported significantly fewer menstrual disturbances.

In addition, the daily symptoms of long Covid were studied over 3 months in 54 women: these intensified in the premenstrual phase, but also during and just after menstruation, including fatigue, headaches, brain fog, breathing difficulties and muscle pain.

Hormone and inflammation levels were also measured in some of the participants, both with and without long Covid , using blood samples and tissue from the uterine lining. The results? The women with long Covid had elevated levels of 5α-dihydrotestosterone, a natural androgen but present at much lower levels under normal circumstances.

"Androgens promote the creation, migration, and survival of stromal cells—a type of tissue cell—within the uterine lining, which are shed during menstruation. According to experts, an increase in these hormones could explain heavier menstrual bleeding in women with long Covid," explains in a press release the University of Edinburgh (Scotland), which participated in the study with the University of Oxford (England) and the University of Montpellier (Hérault).

Progesterone and estradiol levels were identical in women with and without long Covid, suggesting that long Covid does not significantly affect ovarian function.

Towards treatments adapted to women?

Another piece of information: Blood inflammation levels were higher when women suffered from long-term Covid. "This could also contribute to problematic bleeding and influence the severity of symptoms during menstruation, the scientists suggest," the University of Edinburgh analyzes.

Heavy periods lead to iron deficiency, which itself causes fatigue, shortness of breath, headaches, dizziness, and more, in addition to the symptoms of long-term Covid. The study's authors believe it's essential to quickly identify menstrual disorders and offer treatment to affected women.

"It is important to consider the potentially bidirectional relationship between the disease and menstruation, where symptoms vary over the course of the menstrual cycle and the disease influences cycle parameters. We demonstrate here that this could be the case for long Covid, where it is associated with abnormal uterine bleeding and where symptoms appear as menstruation approaches," emphasizes Alexandra Alvergne, a researcher at the CNRS.

Dr. Jackie Maybin of the University of Edinburgh said, "This study is the first step toward specific treatments for menstrual disorders in women with long Covid and could also lead to new treatments for the symptoms of long Covid, tailored to women."