It is a process as old as humanity itself, yet there is still much we do not know about women’s menstrual cycle and the impact it has on the entire body. Now, a team of researchers from the Department of Clinical Medicine at Aarhus University has, for the first time, demonstrated that the cycle affects a wide range of proteins in the female body, explains Associate Professor Jonas Ghouse, one of the researchers behind the study.
“The study shows that the body’s building blocks – proteins, change to a far greater extent during the menstrual cycle than previously recognised,” he says.
This is the first time that protein variation in the blood has been mapped on such a large scale across the menstrual cycle. In total, the researchers identified nearly 200 proteins that change systematically throughout the cycle. This provides an entirely new, comprehensive picture of the biological changes that occur in the body over a full cycle, says Dr Iben Riishede from the Department of Gynaecology and Obstetrics at Aarhus University Hospital, a co-author of the study:
“Previous studies have typically been small or focused on individual hormones. Our study shows that the cycle affects many biological systems, including the immune system, and that these changes are also linked to specific diseases,” she says.
Among the nearly 200 proteins identified by the researchers, several can be linked to conditions such as endometriosis, uterine fibroids and bleeding disorders – and this may have implications for how we understand and measure these diseases in women in the future, says Jonas Ghouse.
“We can see that several of the proteins are associated with these conditions, which many women suffer from. This suggests that the biological changes throughout the cycle may play a role in why some women develop diseases such as endometriosis, which can be severely debilitating.”
The study significantly expands our understanding of the menstrual cycle and how it affects the body. Jonas Ghouse and Iben Riishede therefore hope to continue their research in order to explore the cycle’s effects in even greater depth.
“It is important that we gain a deeper understanding of how the female body works in step with the menstrual cycle – this is relevant both for researchers and for clinicians working with women’s health, fertility and conditions such as endometriosis. For example, it would be valuable to investigate further whether these proteins could be used as biomarkers for specific diseases,” says Jonas Ghouse.
Nature Medicine
Plasma proteomic signature of the human menstrual cycle
13-Apr-2026