Doctors have noted that women experiencing long Covid may face longer, heavier menstrual periods, potentially increasing their risk of iron deficiency, which can worsen the symptoms often associated with the condition.

The conclusion comes from a UK study involving over 12,000 women, revealing that the severity of long Covid symptoms fluctuates with the menstrual cycle and intensifies during menstruation.

Early investigations showed hormonal changes and notable inflammation of the womb lining in women with long Covid, although further research is necessary to understand the broader implications. No evidence indicates that long Covid adversely affects ovarian function.

This suggests a mutual interaction where long Covid influences menstrual cycles, while hormonal variations during these cycles impact the severity of long Covid symptoms.

“We hope this research will enable us to create targeted treatments for women with long Covid experiencing menstrual issues,” stated Dr. Jacqueline Maybin, a gynaecologist at the University of Edinburgh. “It might also pave the way for treatments uniquely suited to women with long Covid, notably affecting those of reproductive age.”

Globally, an estimated 400 million people either live with or have recovered from long Covid, with nearly 2 million in England alone self-reporting symptoms lasting at least four weeks post-infection.

Doctors have recorded more than 200 long Covid symptoms, but the most common include fatigue, brain fog, difficulty breathing, digestive issues, headaches and changes to smell and taste. The ailments appear to be driven by an array of problems, from residual infection and ongoing inflammation to disruption of the immune system and mitochondria, the powerhouses of the cells.

Maybin and her colleagues analysed data from 12,187 UK women who completed an online survey between March and May 2021. More than 1,000 had long Covid, while more than 1,700 had recovered from the virus. More than 9,400 had never tested positive for Covid.

Women with long Covid had longer, heavier periods and more bleeding between their periods than other women, the researchers found. A follow-up survey with 54 women revealed that the severity of their symptoms fluctuated over the menstrual cycle and worsened in the two days before and during their periods.

The researchers went on to analyse blood from 10 women with long Covid. Tests revealed inflammation in the womb lining and higher-than-usual levels of the hormone dihydrotestosterone. Both could be drivers of heavier periods.

Importantly, according to the study in Nature Communications, the tests found no evidence that long Covid harmed the normal functioning of the ovaries.

Many women of child-bearing age are iron-deficient, and heavy periods often contribute to the issue. This leads to symptoms such as fatigue, shortness of breath and dizziness, all of which are common in long Covid. “If you have long Covid on top of iron deficiency, it’s unsurprising that these women are really debilitated and unable to function,” Maybin said.

Dr Viki Male, who studies reproductive immunology at Imperial College London, said inflammation in the uterus was associated with heavy menstrual bleeding, so this could be the link between long Covid and prolonged or heavy periods. “Anti-inflammatory drugs are already used to treat heavy periods, so these findings suggest they might also be helpful for people who experience heavy menstrual bleeding as a symptom of long Covid,” she said.