The integrated balance between bleeding and clotting in girls' and women's health
Throughout their lives, women and girls navigate a delicate balance between bleeding and blood clotting, one shaped by natural hormonal changes and reproductive events from childhood through pregnancy, postpartum and menopause.
Each life stage presents distinct challenges where bleeding and clotting risks intersect, yet the signs are often missed or dismissed. Symptoms can include frequent nosebleeds, easy bruising, very heavy periods or blood clots during pregnancy or after childbirth. In fact, about 1 in 3 women experience heavy menstrual bleeding, which may be a sign of an underlying bleeding disorder.
During pregnancy and after delivery, serious bleeding and dangerous blood clots can become life-threatening if not recognized and treated quickly. Understanding this balance and knowing when to seek medical care can help women and families get the support and treatment they need earlier.
Every stage of life:
Why women’s blood health matters
Women's blood health matters at every life stage because bleeding and clotting risks shift with each major hormonal transition, from a girl's first period through the reproductive years, pregnancy, postpartum recovery and perimenopause and beyond. Each stage brings its own warning signs, and knowing what to watch for helps women and girls advocate for their health and seek care sooner. Discover how these risks change across the lifespan below.
Puberty and menstruation
At menarche, a girl's system must establish normal menstrual hemostasis. Coagulation factor deficiency is not the most common cause of excessive menstrual or peripartum bleeding, but subjects with inherited disorders of coagulation experience excessive (sometimes fatal) uterine bleeding related to menstruation.
Many bleeding disorders, particularly von Willebrand disease, are first diagnosed because of heavy menstrual bleeding at this stage.
The challenge: Clinicians must distinguish between a normal heavy period and a pathologic bleeding disorder when hormone-driven menstrual cycles are still establishing themselves.
Reproductive years and pregnancy
This is where the balance becomes precarious. Exogenous hormonal contraception may increase thromboembolism risk, with using the lowest effective dose critical for prevention. More specifically, modern 'low dose' oral contraceptives are associated with a 3-6 time increased relative risk of venous thromboembolism. But the clinical picture is complex: women with undiagnosed bleeding disorders need safe contraception, yet hormonal contraceptives carry thrombotic risk.
For women with thrombophilia who require hormonal contraception, the least thrombogenic formulations like the levonorgestrel IUD or implant are recommended, though in some situations, the benefits of estrogen-containing contraceptives may outweigh the VTE risk.
Pregnancy: The most critical shift
Pregnancy fundamentally alters the hemostatic balance in both directions simultaneously, creating the highest-risk period for both bleeding and thrombosis.
The prothrombotic state: Thrombosis risk begins early in the first trimester of pregnancy and is strongly correlated with increasing estradiol and progesterone levels. The numbers are striking: the baseline risk for thrombosis in nonusers of contraception was 4.4 per 10,000 person-years, which increased to 29.1 per 10,000 person-years during pregnancy. Additionally, the risk of venous thromboembolism in pregnant women is increased 4-5 times compared to non-pregnant women and then increases to 20 times during the postpartum period.
Pregnancy naturally shifts the body's clotting system into high gear. Levels of von Willebrand factor, factor VIII, fibrinogen, and other clotting factors all rise, while the natural anticoagulant protein S and fibrinolytic (clot-dissolving) activity decrease. Platelet counts may drop slightly, but platelets become more active and reactive. This hypercoagulable (increased clotting) state is the body's way of preparing for childbirth, but it can also mask underlying bleeding disorders, making them harder to detect. For this reason, a definitive diagnosis of a bleeding disorder should only be made when clotting levels have returned to baseline outside of pregnancy. If a bleeding disorder is suspected, your doctor may refer you to a hemophilia treatment center or a hematologist with expertise in bleeding disorders for specialized evaluation and care.
Perimenopause and beyond
Hormonal substitution treatment increases the risk of venous thromboembolism, in particular in the first year of use. As women transition out of reproductive years, hormone replacement therapy (HRT) can recalibrate the hemostatic balance again, increasing thrombotic risk in women who may have underlying, undetected bleeding disorders.
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