Heavy periods can be an early sign of a hereditary bleeding disorder, but this link is still frequently overlooked. As a result, women suffer from symptoms for an unnecessarily long time and face an increased risk of severe bleeding, for example during childbirth. Doctor and researcher Anne de Vaan investigated how care for girls and women with a hereditary clotting disorder can be improved. She was awarded her PhD on 20 May 2026 at UMC Utrecht.
Hereditary bleeding disorders are often seen as conditions that mainly affect men. Yet women also experience many symptoms. This is partly because menstruation, childbirth and other forms of vaginal bleeding place a significant strain on the blood clotting system. “For many women, heavy menstrual bleeding is the first symptom of a bleeding disorder,” says Anne de Vaan. “But young girls often don’t recognise this as abnormal, because their mother or grandmother had the same thing.”
In a blood clotting disorder, part of the natural clotting system does not work as well as it should. Normally, platelets and clotting factors work together to form a strong blood clot. If one of these factors is missing or does not function properly, bleeding occurs more quickly and lasts longer. As a result, people may suffer from heavy periods, post-operative bleeding, bleeding gums and anemia caused by chronic blood loss.
In her PhD research, Anne de Vaan focused, among other things, on adolescents with heavy menstrual bleeding. More than 30 per cent of young people report heavy periods. This is often due to an immature hormonal cycle, but sometimes it is caused by an inherited bleeding disorder.
To gain a better understanding of the severity of menstrual symptoms, Anne de Vaan used the Pictorial Bleeding Assessment Chart (PBAC), a menstrual calendar designed to track blood loss. An app and social media were used to investigate how common heavy menstrual bleeding is among young people. According to the PBAC, 22 per cent of participants experienced heavy menstrual bleeding.
She also investigated how often young people with these symptoms visit their GP and what care they subsequently receive. The study shows that relatively few adolescents visit their GP for this reason. Those who do visit are often prescribed hormonal contraception, whilst additional blood tests are rarely carried out. “This creates a risk that an underlying bleeding disorder may go unrecognised,” says Anne de Vaan.
She also looked at the optimal timing for diagnosis. The levels of key clotting factors, such as von Willebrand factor and factor VIII, were found not to vary across the different phases of the menstrual cycle. This means that blood tests for the diagnosis of a bleeding disorder can be carried out at any time.
The second part of the study focused on women with von Willebrand disease and carriers of haemophilia during pregnancy and childbirth. These women are at increased risk of severe bleeding after childbirth, also known as postpartum haemorrhage or fluxus.
To reduce this risk, women with low clotting factor levels are given additional clotting factors during pregnancy. Since 2018, the Dutch guideline has recommended treating more women preventively and maintaining higher target levels.
Anne de Vaan investigated whether this more intensive treatment led to fewer severe bleeds. This turned out not to be the case. Despite more treatment, the risk of severe postpartum haemorrhage remained the same. However, the risk of complications, such as thrombosis, did not increase. She also investigated the impact on quality of life and the experience surrounding childbirth. Women with a blood clotting disorder recovered more slowly six weeks after giving birth than women without a clotting disorder, but at the same time were remarkably satisfied with their childbirth experience and the care they received.
According to Anne de Vaan, her research shows that greater attention needs to be paid to women-specific symptoms within haemophilia care. Early detection of bleeding disorders can help prevent unnecessary symptoms, emba
rrassment and medical complications.
Anne de Vaan’s research was carried out at the Van Creveld Clinic Haemophilia Centre of Expertise at UMC Utrecht. Here, specialists work on the diagnosis, treatment and research of inherited bleeding disorders in children and adults.
