Blood clots

Data shows that contraceptive drugs increase the risk of blood clots. Proponents for hormonal birth control argue that the increased risk in young women was a small risk to start with (between 1 and 5 of every 10,000 women), and that the increase isn’t drastic (between 3 and 9 of every 10,000). Not all forms of hormonal birth control have been shown to increase the risk of blood clots—just those that contain estrogen or certain types of progestin, which happen to be among the most popular. They include the Pill, Beyaz, Yasmin, Yaz, NuvaRing, Xulane, and Nexplanon.

Some compare the risk of blood clots while on birth control to the risk of blood clots that a woman has while pregnant or postpartum. It’s noted that the natural increase in estrogen that occurs during pregnancy and the postpartum period is much greater than what one experiences on birth control, and thus the risk of blood clots is much more elevated while pregnant or postpartum (between 5 and 20 of every 10,000 pregnant women, and 40 to 65 of every 10,000 postpartum women). First, it’s odd to compare the risks of birth control to risks inherent in pregnancy, considering one is a natural physical process and the other is the side effect of a drug—a drug that can expose women to the increased risk for blood clots for as long as she uses birth control, which could be for many years in a row. Second, the estrogen contained within hormonal contraceptives is synthetic, and not the same as naturally occurring, endogenous estrogen.

By increasing the risk of blood clots, stroke, and heart attack, hormonal contraception leads to the death of 300-400 women every year. For perspective, 415 people died of meningitis in 2023. Most states mandate meningitis vaccination for college and university students. Would they consider the same kind of prevention campaigns for the deadly blood clots caused by hormonal birth control?


Click a subtopic below to view scientific references for each of the following and their connections to birth control use.

Bloemenkamp KWM, Rosendaal FR, Büller HR, Helmerhorst FM, Colly LP, and Vandenbroucke JP. Risk of venous thrombosis with use of current low-dose oral contraceptives is not explained by diagnostic suspicion and referral biasArch Intern Med 1999; 159:65–70.

Bloemenkamp KWM, Rosendaal FR, Helmerhorst FM, Büller HR, and Vandenbroucke JP. Enhancement by factor V Leiden mutation of risk of deep-vein thrombosis associated with oral contraceptives containing a third- generation progestagenLancet 1995; 346:1593–1596.

Dinger J, Assmann A, M€ohner S, and Minh TD. Risk of venous thromboembolism and the use of dienogestand drospirenone-containing oral contraceptives: results from a German case-control studyJ Fam Plann Reprod Health Care 2010; 36:123–129.

Dinger J, Bardenheuer K, and Heinemann K. Cardiovascular and general safety of a 24-day regimen of drospirenonecontaining combined oral contraceptives: final results from the International Active surveillance Study of Women Taking Oral ContraceptivesContraception 2014; 89(4):253–263.

Dinger JC, Heinemann LAJ, and Ku¨hl-Habich D. The safety of a drospirenone-containing oral contraceptive: final results from the European Active Surveillance study on oral contraceptives based on 142,475 women years of observationContraception 2007; 75:344–354.

Farmer RDT, Lawrenson RA, Thompson CR, Kennedy JG, and Hambleton IR. Population-based study of risk of venous thromboembolism associated with various oral contraceptivesLancet 1997; 349:83–88.

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Gomer K. Women, Birth Control Pills, and Thrombophilia: An Analysis of Risk Communication Kerry Gomer, Clemson University. 2009;

Gronich N, Lavi I, and Rennert G. Higher risk of venous thrombosis associated with drospirenone-containing oral contraceptives: a population-based cohort studyCMAJ 2011; 183(18):E1319-25.

Jick H, Jick SS, Gurewich V, Myers MW, and Vasilakis C. Risk of ideopathic cardiovascular death and nonfatal venous thromboembolism in women using oral contraceptives with differing progestagen componentsLancet 1995; 346:1589-1593.

Jick SS, and Hernandez RK. Risk of non-fatal venous thromboembolism in women using oral contraceptives containing drospirenone compared with women using oral contraceptives containing levonorgestrel: case-control study using United States claims dataBritish Medical Journal 2011; 340:d2151.

Keenan L, Kerr T, Duane M, and Van Gundy K. Systematic Review of Hormonal Contraception and Risk of Venous ThrombosisThe Linacre Quarterly 2018; 85(4):470–477.

Le Moigne E, Delluc A, Tromeur C, Nowak E, Mottier D, Lacut K, and Le Gal G. Risk of recurrent venous thromboembolism among young women after a first event while exposed to combined oral contraception versus not exposed to: a cohort studyThromb Res 2013; 132:51–55.

Lewis MA, MacRae KD, Kűhl-Habich D, Bruppacher R, Heinemann LA, and Spitzer WO. The differential risk of oral contraceptives: the impact of full exposure historyHum Re prod 1999; 14:1493–1499.

Lidegaard Ø, Edstr€om B, and Kreiner S. Oral contraceptives and venous thromboembolism. A five-year national case-control studyContraception 2002; 65:187–196.

Lidegaard Ø, Løkkegaard E, Svendsen AL, and Agger C. Hormonal contraception and risk of venous thromboembolism: national follow-up studyBritish Medical Journal 2009; 339:b2890.

Lidegaard Ø, Nielsen LH, Skovlund CW, and Løkkegaard E. Venous thrombosis in users of non-oral hormonal contraception: follow-up study, Denmark 2001–10British Medical Journal 2012; 344:e2990.

Lidegaard Ø,Nielsen LH, Skovlund CW, Skjeldestad FE, and Løkkegaard E. Risk of venous thromboembolism from use of oral contraceptives containing different progestogens and estrogen doses: Danish cohort study 2001–2009British Medical Journal 2011; 343:d6423.

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Parkin L, Sharples K, Hernandez RK, and Jick SS. Risk of venous thromboembolism in users of oral contraceptives containing drospirenone or levonorgestrel: nested case-control study based on UK General Practice Research DatabaseBritish Medical Journal 2011; 340:d2139.

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Yasmin Prescribing Information: Highlights of Yasmin Prescription Information,

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This article was last updated on March 21, 2024.

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