Claim: The birth control pill increases the risk of blood clots

First requested: June 22, 2026 at 5:33 PM
87%

IsItCap Score

Truth Potential Meter

Very Credible

AI consensusWeak

Grader consensus is weak.
Range 80%–97% (spread Δ17).
The graders diverge. Treat the combined score as uncertain and read the sources carefully.
Read analysis summary

OpenAI Grade

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80%

Perplexity Grade

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80%
97%

Google Gemini Grade

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95%
Shareable summary
Verdict: Questionable
  • Risk varies by formulation; progestin-only pills may not raise it much.
  • Some sources emphasize the increase is small in absolute terms.
/r/birth-control-pill-blood-clot-risk

Analysis Summary

The claim that the birth control pill increases the risk of blood clots is mostly true. Mainstream medical sources, including the Cleveland Clinic and the American Society of Hematology, support this assertion, noting that hormonal contraceptives can elevate blood clot risk significantly. However, some sources emphasize that the absolute risk remains low and varies by formulation, with progestogen-only pills posing little risk. Critics argue that the risk is often overstated, particularly when compared to the risks associated with pregnancy. The graders agree on direction, but vary in strength. Perplexity comes in highest (97%), while OpenAI is lowest (80%). While the majority of evidence supports the claim that the birth control pill increases blood clot risk, some sources highlight that the risk is very small and contingent on specific formulations. For instance, progestogen-only pills are noted to have little to no increased risk. This nuance does not fundamentally alter the overall conclusion but suggests that the degree of risk can vary significantly among different types of contraceptives, which may lead to differing interpretations of the claim's implications.
Jump to source analysis

Source quality

Truth (from sources)8.00 / 10
Source reliability8.00 / 10
Source independence7.00 / 10

Claim checks

Fits established facts7.00 / 10
Logical consistency8.00 / 10
Expert consensus8.00 / 10
Related fact checks

Source Analysis

Common arguments
Supporting the claim
  • Estrogen-containing pills raise clot risk versus nonusers.
  • Absolute risk is still low, but not zero.
  • Risk drops after stopping hormonal contraceptives.
Against the claim
  • Risk varies by formulation; progestin-only pills may not raise it much.
  • Some sources emphasize the increase is small in absolute terms.
  • Pregnancy can pose a higher clot risk than the pill.

Mainstream Sources

Publication

health.clevelandclinic.org

Title

Does Birth Control Cause Blood Clots?

Summary

Cleveland Clinic explains that hormonal birth control containing estrogen can increase blood clot risk, though the absolute risk is small.

Source details

Type: Primary

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URL

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Publication

hematology.org

Title

Blood Clotting Risk Quickly Drops After Stopping Hormonal Contraceptives

Summary

The American Society of Hematology reports that combined hormonal contraceptives are known to elevate blood clot risk, roughly three-fold, and that the risk declines soon after stopping them.

Source details

Type: Primary
Published: 2023-11-08
Press Release

URL

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Publication

pmc.ncbi.nlm.nih.gov

Title

Risk of venous thromboembolism with oral contraceptives

Summary

This peer-reviewed article states that combined oral contraceptives increase venous thromboembolism risk, while absolute risk remains low for most users.

Source details

Type: Primary
Official DocOutdated

URL

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Alternative Sources

Publication

medsafe.govt.nz

Title

Oral Contraceptives and Blood Clots

Summary

This source does not contradict the claim; it qualifies it by emphasizing that the risk is very small and varies by formulation.

Source details

Type: Official
Official Doc

URL

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Publication

myhealth.alberta.ca

Title

Hormonal Birth Control: Risk of Blood Clots

Summary

This source also supports the claim but adds that some progestins may carry different levels of risk and that pregnancy risk is higher than pill-related risk.

Source details

Type: Official
Official Doc

URL

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Analysis Breakdown

True/False Spectrum (8.0)Source Credibility (8.0)Bias Assessment (7.0)Contextual Integrity (7.0)Content Coherence (8.0)Expert Consensus (8.0)77%

How to read the breakdown

Weakest areas
Independence7.0/10Context7.0/10
  • Truth: how well sources support the core claim.
  • Source reliability: whether the sources have a strong track record.
  • Independence: whether coverage looks one-sided or recycled.
  • Context: missing details (timeframe, definitions, scope) that change meaning.
  • Tip: if graders disagree, rely more on the summary + sources than the single number.

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Methodology