Health
“Long-term birth control pill use, such as taking it for 10 years or more, increases a woman's risk of developing hypothyroidism by 283.7%, according to a study published in the British Medical Journal.”
Plain restatementA study in a BMJ-group journal reported an association between taking oral contraceptive pills for more than 10 years and higher odds of hypothyroidism, with an adjusted odds ratio of 3.837 (equivalent to a 283.7% increase in odds, not risk).
General information only - not medical advice.
The 283.7% figure comes from a real 2021 study, but the claim misrepresents what that study showed. The study was published in BMJ Open, which is a separate open-access journal, not the British Medical Journal. It reported an odds ratio of 3.837 for women who had used the pill for more than 10 years, and 3.837 is where "283.7%" comes from. But that is an increase in odds rather than risk, it rests on a subgroup of only 376 women, and the margin of error was enormous, meaning the true effect could be anywhere from very small to very large. The study's own authors wrote that their design could not show cause and effect. A larger 2024 study that followed more than 18,000 women over time found the opposite, with slightly fewer hormonal contraceptive users developing hypothyroidism than non-users. There is also a known technical issue where the pill changes thyroid blood test readings without actually changing thyroid function, which can make results look abnormal when they are not. Anyone with questions about their thyroid or their contraception should discuss them with their own clinician and should not stop a prescribed medication based on a social media post.
[drifted from the evidence:] Long-term birth control pill use, such as taking [drifted from the evidence:] it for 10 years [drifted from the evidence:] or more, increases a woman's risk of [drifted from the evidence:] developing hypothyroidism [drifted from the evidence:] by 283.7%, according to a [drifted from the evidence:] study published in [drifted from the evidence:] the British Medical Journal.
[added by the neutral restatement:] A study in a BMJ-group journal reported an association between taking [added by the neutral restatement:] oral contraceptive pills for [added by the neutral restatement:] more than 10 years [added by the neutral restatement:] and higher odds of hypothyroidism, [added by the neutral restatement:] with an adjusted odds ratio of 3.837 (equivalent to a [added by the neutral restatement:] 283.7% increase in [added by the neutral restatement:] odds, not risk).
Red-tinted words in the claim drifted from the evidence. Green-tinted words are what a neutral restatement needs.
The trace / claim to source
- A real peer-reviewed study reporting this figure exists. The number 283.7% is a faithful arithmetic translation of the published adjusted odds ratio of 3.837.
- The study did find a statistically significant association between more than 10 years of birth control pill use and hypothyroidism, after adjustment for several confounders.
- The study is published by the BMJ publishing group.
- The study did find that short-term use was not associated with hypothyroidism, consistent with the claim's emphasis on long-term use.
- Unsupported causal inference. The claim says pill use "increases a woman's risk." The study is cross-sectional and its authors state explicitly that the relationship was not necessarily causal. The post's caption goes further, asserting a "direct correlation" and framing birth control as a cause of the speaker's own hypothyroidism.
- Statistical misstatement. An odds ratio of 3.837 is a 283.7% increase in odds, not in risk. For a condition as common as hypothyroidism these are not interchangeable, and the conversion inflates the number presented to a lay audience.
- Omitted qualifier (precision). The 95% CI of 1.402 to 10.500 is not mentioned. Quoting "283.7%" to one decimal place implies a settled, precise finding from a result that is statistically fragile and rests on a subgroup of only 376 women.
- Source misattribution. "British Medical Journal" is not the journal that published this study. BMJ Open is a separate open-access title.
- Omitted contradicting evidence. A larger 2024 study using a longitudinal design and more than 18,000 women reported a decreased incidence of hypothyroidism among hormonal contraceptive users. Presenting one cross-sectional finding as settled science ("scientifically proven") ignores a directly conflicting body of evidence.
- Omitted methodological confound. Oral contraceptives are known to raise thyroid-binding globulin and alter total thyroid hormone measurements without changing free hormone levels, a recognised source of misclassification that the viral claim does not acknowledge.
- Marketing as evidence. The claim is attached to a call to action for a paid or gated "masterclass on how to heal your thyroid," which gives the speaker a commercial interest in the strength of the framing.
- Whether any genuine causal relationship exists between long-term oral contraceptive use and hypothyroidism. The published evidence is genuinely conflicting and no randomised trial addresses this question.
- The exact biochemical definition of hypothyroidism used by Qiu et al. and the number of hypothyroid cases within the 376-woman long-duration subgroup were not retrieved in full. This matters because a small case count would further explain the wide confidence interval.
- The secondary claim in the transcript, that birth control pills deplete B2, B6, folate, B12, zinc, magnesium, selenium, vitamin C and probiotics, was not investigated here. Some nutrient-level associations with oral contraceptive use do appear in the literature, but the claim that this has been "scientifically proven" across all nine listed items, and that it causes clinical deficiency, was not verified. Treat it as uninvestigated.
A real study with a figure matching the claim exists. Qiu et al. analysed NHANES 2007-2012 data and included 5116 adult women, 3034 with a history of taking birth control pills and 2082 without, and found a higher prevalence of hypothyroidism among those who had ever taken them. After adjustment for age, race, first menstrual age, pregnancy history, menopause status and history of hormone replacement use, the analysis showed a significant association between a history of taking birth control pills for more than 10 years and hypothyroidism, with an odds ratio of 3.837 and a 95% confidence interval of 1.402 to 10.500. An odds ratio of 3.837 is where "283.7%" comes from, since 3.837 minus 1 equals 2.837. The study's own framing is more restrained than the claim. The authors list as a limitation that the data were derived from cross-sectional studies and that the relationship was not necessarily identified as causal. They also state that specific birth control medications were not available in NHANES, which they call the main limitation of their study, and that the cross-sectional nature did not allow investigation of a causal relationship. The study also found that short-term use of birth control pills was not associated with hypothyroidism. The broader literature does not point in one direction. A larger study with a longitudinal design reached the opposite conclusion. In that study, 118 individuals (1.8%) in the control group and 165 individuals (1.4%) who received hormonal contraception developed hypothyroidism, across groups described as estrogen-progestin contraceptive use n=5849, progestin-only n=5052, IUD n=1000, and controls n=6677. The authors describe this study of more than 18,000 women as demonstrating a protective effect of hormonal contraception on the risk of developing hypothyroidism. A separate 2025 Qatar Biobank analysis of 1001 women also revealed no increased odds of hypothyroidism at the 90th percentile cutoff for SHBG levels (OR 1.00, 95% CI 0.29 to 3.50). There is a known measurement complication in this area. In women using oral contraceptives, levels of total T3 and T4 rise because of increased serum binding capacity of thyroxine-binding globulin, while increased serum binding reduces the free proportion, so free T3, free T4 and thyroid function may be unchanged during treatment. An increase in thyroid-binding globulin may raise total T4 and T3 while free T4 and TSH remain normal, without an increase in hormone activity in the body.
Complete reasoning
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Answers come only from the case file above; nothing is added.
Is the 283.7% figure made up?
No, it comes from a real 2021 study, which found an odds ratio of 3.837 for women who had used birth control pills for more than 10 years. Converting that odds ratio into a percentage gives 283.7%, but that describes an increase in odds, not an increase in risk.
Was this study really published in the British Medical Journal?
No. It was published in BMJ Open, which is a separate open-access journal from the British Medical Journal, even though both are part of the same publishing group.
Does this mean birth control pills cause hypothyroidism?
The study cannot show that. It used a cross-sectional design, and its own authors stated the relationship was not necessarily causal. A larger 2024 study following more than 18,000 women over time found the opposite result, with fewer hormonal contraceptive users developing hypothyroidism than non-users.
How reliable is the 283.7% number itself?
It rests on a small subgroup of only 376 women and has a very wide confidence interval, from 1.402 to 10.500, meaning the true effect could be much smaller or much larger than reported. Quoting it to one decimal place makes it look more precise and settled than the data actually support.
Could something else explain the higher thyroid test results in pill users?
Yes. Oral contraceptives are known to raise thyroid-binding globulin, which increases total T3 and T4 levels on blood tests without necessarily changing actual thyroid function, since free hormone levels often stay normal. This is a recognized source of misleading results that the original claim does not mention.