Genetic Predisposition for Blood Clots and Birth Control Are Linked

A recent study from Uppsala University found that women who have a strong genetic tendency for blood clots are six times more likely to get a blood clot during the first two years of taking contraceptive tablets.

An increased risk of blood clots has already been associated with the usage of combination hormonal contraceptive tablets. For instance, the World Health Organization has issued a warning that women who have known mutations associated with inherited thrombophilia — a disorder in which the blood coagulates too readily — may not want to use the contraceptive pill due to the unacceptable health risk.

Blood clots are gel-like or semi-solid lumps that develop in your veins and arteries. Blood clots aid in the management of bleeding, but they can also result in dangerous medical conditions like heart attack, pulmonary embolism, and deep vein thrombosis.

One of the study's authors, Valeria Lo Faro, claims that the research is crucial for understanding women's health and may be useful in advising on contraception.

In addition to the known mutations, several more genes have been found to impact blood clot risk; taken together, these genes raise an individual's overall risk.

Simple, low-cost techniques may be used to assess an individual's genetic risk, which can then be summarized as a genetic risk score. A lower genetic risk score indicates a reduced genetic risk, whereas a larger genetic risk score suggests the presence of numerous genetic risk factors.

Lo Faro notes that they looked at data from 244,420 British women from the UK Biobank to explore the relationship between a person's hereditary risk of blood clots and their usage of contraceptive tablets.

According to the research, women with high genetic risk scores had a six-fold higher risk of blood clots over the first two years of using birth control pills than did women with low genetic risk scores.

Using this information, women who have a high risk of blood clots might be identified. They can then receive advice on non-hazardous alternate methods of contraception.

Genetic risk profiles for many common diseases can now be determined all at the same time, for example, from blood tests taken at birth. We predict that this type of genetic risk projection will play an important role in counseling and risk predictions in the future.

- Åsa Johansson, study co-author

According to the study, assessing polygenic risk can reveal new risk factors for venous thromboembolism that are not included in the genes for hereditary thrombophilia that are frequently studied.

The findings suggest that using oral contraceptives raises the risk of venous thromboembolism, especially in women with a high genetic predisposition. The risk increases significantly shortly after starting oral contraceptive use and then declines with continued use.