Disturbing Facts Associated With Your Birth Month
Scientists have spent years noticing something odd when they zoom out and look at birth data across entire populations: the time of year you’re born sometimes lines up with certain health trends later in life. When you track millions of births, those tiny differences start forming patterns that researchers still argue about today.
January
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Global schizophrenia data maps show more diagnoses among people born during the deepest winter months. January sits right in that window. One major theory focuses on late-pregnancy sunlight exposure, since vitamin D plays a role in brain development. Winter pregnancies also line up with peak cold and flu seasons, which researchers think may influence fetal immune development.
February
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February comes up in two completely different conversations. Some psychiatric studies place it near winter schizophrenia risk trends, while creativity research sometimes finds February birthdays overrepresented in artistic careers. Scientists are still trying to understand whether seasonal immune exposure, light cycles, or early timing of brain development could connect those dots.
March
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Extensive hospital record reviews first spotted the March pattern while tracking long-term heart admissions. March birthdays appeared slightly more often in certain heart rhythm and heart failure categories. The difference is small, but it is consistent across multiple population studies spanning different countries and healthcare systems.
April
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One of the largest UK suicide datasets ever compiled showed a noticeable birth-month clustering that repeatedly pointed toward April. The study tracked nearly 27,000 cases over the course of decades. The numbers do not apply to individuals, but the consistency across long-term data made the pattern statistically difficult to ignore.
May
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In several European and U.S. population studies tracking mood disorder diagnoses, May birthdays showed a small but noticeable peak compared to surrounding months. The pattern appears in large healthcare datasets. The difference is modest, but it has been observed across multiple long-term analyses of mental health records spanning different countries.
June
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When British public health teams reviewed decades of national death records, they expected a random distribution of births. Instead, June kept appearing slightly above average in long-term suicide data. The increase is small, but it repeated across multiple reporting periods, which is why June still shows up in population-level mental health discussions today.
July
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If you graph schizophrenia diagnoses across the calendar year, summer births usually sit lower than winter ones. July often lands near that dip. This pattern has appeared in multiple international datasets comparing millions of records, which is why researchers sometimes use midsummer births as a contrast point when studying seasonal trends in psychiatric risk.
August
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In some large national mental health registries, August births appear slightly less often in bipolar disorder diagnosis records compared with yearly averages. The difference has been repeated across multiple long-term population studies, including datasets tracking millions of patients across Europe and North America.
September
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National health registry comparisons in countries like Sweden and Denmark have shown slightly higher alcohol use disorder diagnosis rates among people born in early autumn, including September. In several of those national datasets, September consistently ranked among the top three birth months with the highest AUD diagnosis rates.
October
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A Columbia University medical data project linking birth month and disease risk found October births connected to higher rates across multiple conditions, including asthma, respiratory infections, and certain cardiovascular issues. In that dataset, October showed the highest number of individual disease correlations of any month.
November
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When seasonal birth trends are mapped against depression treatment data, late-year births sometimes stand out for what they don’t show. In several European national prescription and diagnosis registries, November consistently landed near the bottom of annual depression diagnosis rankings across multi-decade population tracking.
December
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One of the longest-running U.S. population health projects, the Nurses’ Health Study, tracked more than 100,000 women for decades while monitoring cardiovascular outcomes. Participants born in December showed the lowest heart-disease-related mortality rates. The difference was most noticeable when compared with participants born during late winter and early spring months.