Combined pills do raise clot risk, and that risk rises with age, but the absolute numbers stay fairly low for most healthy women without added risk factors.

To put the numbers in context, pregnancy itself carries a considerably higher clot risk than any pill formulation. Direct comparison data in women over 50 found combined pill users had a substantially higher clot risk than users of standard menopausal hormone therapy taken by mouth, and non-oral (transdermal) hormone therapy showed no increased clot risk at all in that same study. This is one of the more evidence-backed reasons clinicians favor switching off combined pills around age 50.

What to know about this answer

There is no real dispute that combined pill clot risk rises with age; the open question flagged in the source material is what to do about it, since the guideline body itself names the safety of combined pills specifically in women over 50 as a gap with no dedicated evidence on either side.

What the research shows, and which source each finding rests on

Per 10,000 healthy women over one year, clot risk is about 2 with no combined pill use and not pregnant, 29 during pregnancy, 5 to 7 with pills containing levonorgestrel, norgestimate or norethisterone, and 6 to 12 with pills containing other progestins such as etonogestrel, gestodene, desogestrel, or drospirenone.

A[1]

In a large Danish cohort, clot incidence among combined pill users rose from 8.7 per 10,000 woman-years at ages 30-34 to 20.8 per 10,000 woman-years at ages 45-49.

A[1]

In a case-control study of women over 50, combined pill users had a 6.3-fold increased clot risk compared with non-users, oral menopausal hormone therapy carried about a 4-fold increased risk, and non-oral (transdermal) hormone therapy carried no increased risk at all.

C[2]

Guidelines recommend combined pills containing levonorgestrel or norethisterone, and containing 30 micrograms or less of estrogen, as first-line choices for women over 40 because of their comparatively lower clot risk.

A[1]

Where the real disagreement is

Each position is shown with its own sources. A position listed here is not necessarily the accepted view.

the age-related rise in risk argues for switching off the pill by 50

the guideline default and clinicians who favor an earlier switch

Because clot risk rises with age on combined pills, and because the strongest direct comparison study found a much lower risk with non-oral hormone therapy in women over 50, guidelines default to switching women off combined pills at 50.

A[1]C[2]

the safety of continuing past 50 is genuinely unknown, not proven unsafe

the guideline's own stated research gap

Safety of combined pills in women over 50 is named directly as a missing piece of research; there is no dedicated trial showing continuation past 50 is dangerous, only that it has not been specifically studied, which means any advice on either side of this specific question is expert judgment operating without direct evidence.

A[1]

What would settle it: Dedicated safety research on combined pill use specifically in women over 50 would settle this. The guideline body names this as a needed area of future research; it does not yet exist.

What is really going on here

  1. Absolute risk numbers, clot events per 10,000 women per year, are more useful for personal decision-making than relative-risk multipliers, and pregnancy itself carries a higher absolute clot risk than any listed pill formulation.
  2. The strongest single piece of evidence in this area is a case-control study, not a randomized trial, so it shows association, not proof of cause, though it remains the best available direct comparison.

Questions for your doctor

  1. What is my personal, absolute clot-risk estimate on my current pill, given my age and health history?
  2. Would switching to a different progestin or a lower estrogen dose meaningfully lower my risk?
  3. At what point would you recommend I move to a non-oral option instead?
  4. Do I have any risk factors, like smoking or migraine with aura, that change this calculation for me?

Questions with no answer yet

Is combined pill use actually unsafe for women continuing it past age 50, or has this simply never been directly studied on either side?

Not directly studied yet

No research does not mean it does not work, and it does not mean it works. It means nobody has tested it yet.

What is known: Safety of combined pills in women over 50 is named directly as a missing piece of research by the guideline body; there is no dedicated trial showing continuation past 50 is dangerous, only that it has not been specifically studied, meaning advice on either side of this question is expert judgment operating without direct evidence.

What would test it: Dedicated safety research on combined pill use specifically in women over 50; the guideline body names this as a needed area of future research and it does not yet exist.

Would switching a woman from a higher-VTE-risk progestin to a lower-VTE-risk progestin meaningfully lower her personal clot risk, or does age and other risk factors dominate the calculation regardless of progestin choice?

Partly studied

What is known: Per 10,000 healthy women per year, clot risk is 5 to 7 with levonorgestrel, norgestimate, or norethisterone-containing pills, versus 6 to 12 with pills containing other progestins; the difference at the population level is documented, but the source material does not report a study isolating how much an individual woman's personal risk would change from switching progestins specifically, as opposed to other risk factors she carries.

What would test it: A study tracking individual women who switch progestin type, measuring change in clot incidence relative to women who continue their original progestin, controlling for other risk factors.

Sources

  1. 1.FSRH. Contraception for Women Aged Over 40 Years. Guideline, August 2017 (amended September 2019, further amended July 2023).Systematic review or guideline
  2. 2.The risk of venous thrombosis in women over 50 years old using oral contraception or postmenopausal hormone therapy.Roach REJ, Lijfering WM, Helmerhorst FM, Cannegieter SC, Rosendaal FR, van Hylckama Vlieg A. The risk of venous thrombosis in women over 50 years old using oral contraception or postmenopausal hormone therapy. J Thromb Haemost 2013;11(1):124-31. · Observational study

The letter grades the type of study behind a claim, not the answer itself.

This page is general information based on published research and public sources. It is not medical advice and not a personal assessment, and it does not replace a conversation with your doctor. Peritale is a wellness product, not a medical device, and is not intended to diagnose, treat, cure or prevent any disease. For any medical question, speak with a licensed clinician.

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