Gynecologist's Research Documents Menstrual Changes Post-COVID and Vaccination

Dr. Miriam Al Adib is not another voice in the anti-vaccine noise. She just defended a doctoral thesis containing three studies published in top-tier scientific journals, based on research involving 17,512 women—one of the largest datasets assembled to date on a question that has haunted thousands: why did their periods change after COVID or vaccination?

Al Adib, a gynecologist and obstetrician born in Almendralejo on January 1, 1977, spent years pursuing an answer to a problem she kept hearing about in her practice. Women arrived with stories of altered cycle lengths, unexpected bleeding between periods, shifts in flow intensity. Some had menstruations that never returned to normal. "There are women whose periods never went back to how they were before COVID," she says. "Nobody is talking about them." She decided to adapt methodology from a pioneering study at the University of Illinois and test whether the findings held true in Spain.

The research is observational rather than prospective—Al Adib analyzed a large sample retrospectively to detect patterns rather than following women forward in time after vaccination. This means the work can establish associations but not definitive causation. What emerged was a portrait of vulnerability: the vaccine appeared to affect women with specific profiles more severely—those with a tendency toward elevated estrogen, systemic inflammation, obesity, rheumatic diseases, or histories of allergies. COVID itself produced menstrual changes in a different group: women in perimenopause who had always experienced heavy bleeding. For many women, the alterations were temporary. But a subset never recovered their normal cycles even after more than a year had passed. Some developed symptoms resembling long COVID or what researchers call acute post-vaccine syndrome—a condition marked by neurological, vascular, and immune dysfunction that can become chronic and disabling. "Their quality of life is lamentable," Al Adib says.

The three studies that form her thesis examined distinct populations: women without menstruation who contracted COVID, women who received the vaccine, and menstruating women after vaccination. The first study to be published broke new ground simply by including women without periods—until then, no one had thought to include them in this kind of research. They too reported bleeding alterations. What weighs most heavily on Al Adib is the silence that surrounded these experiences. "Thousands of women lived through these changes feeling alone, convinced it had only happened to them, while doctors kept telling them there was no scientific evidence for it," she says. "How much work does it take to include menstruation as a variable in a clinical trial?"

The problem, she insists, is structural. Without sex-differentiated data, women's symptoms dissolve into the general sample and become invisible. "What you don't see, you don't treat," she argues. The three studies were published in Q1 and Q2 journals—those with the highest impact and most rigorous standards—and are indexed in PubMed. But getting there required persistence. Al Adib discovered that gender bias does not stop at the clinic or the trial design; it lives in scientific publishing itself. "The three studies were rejected for years without any methodological arguments. Just silence, or a brief note saying it wasn't a topic of interest." For her, publication is not the destination but the beginning.

Her deeper demand is more urgent: that female health variables, including menstruation—a process that shapes half the population for decades—be systematically incorporated into research. Nausea appears on medication inserts. Why not menstruation? The exclusion of women from clinical trials is not new; in the 1990s, advocacy groups raised the alarm and women were added to studies. But inclusion without sex-differentiated data collection is only a partial solution. "The problem starts even before we get to people," Al Adib notes. "Animal studies choose male rats." The justification for excluding women, she observes with irony, is always the same: female hormonal variability makes conclusions difficult to draw. "In other words, they exclude us precisely for what defines us. And then they don't know how to treat us."

Bringing this critique into academic space has been a personal battle. She has spent years discussing women's health in public writing, but the doctorate was the credential she lacked. "Women have to prove everything three times over," she says. "In 2016 I was writing on my blog about the connection between gut microbiota and endometriosis and it was looked down on. Now everyone talks about it." Credibility, she concludes, should not depend on the gender of the researcher. The consequences of this exclusion are concrete. The female immune system, modulated by hormones, functions differently—it protects more but also attacks more, which explains the higher prevalence of autoimmune disease in women. "Men die earlier, yes, but by a smaller margin than people think," she says. "What doesn't get said is that many women reach an age where their quality of life has deteriorated so much they end up medicated with psychiatric drugs. It's always the same pattern." Even heart attacks take longer to diagnose in women because their symptoms don't match the male model described in medical textbooks. "What doesn't kill you gets ignored." The problem extends to pharmacology: if female metabolism varies across the menstrual cycle, women may be over- or under-medicated with drugs designed and tested on male bodies. Without studies that account for this, no one will ever know.