Hormonal birth control carries real health risks, though most are small in absolute terms. The most well-established concerns include a higher chance of blood clots, a modest increase in breast cancer risk, and a measurable effect on mood, particularly in younger users. The type of birth control matters: combined pills (containing both estrogen and a progestin) carry different risks than progestin-only methods or non-hormonal devices like the copper IUD.
Blood Clots: The Most Serious Short-Term Risk
Combined oral contraceptives increase the risk of venous thromboembolism, which includes deep vein thrombosis and pulmonary embolism. For women not using any hormonal contraception, the baseline rate is about 2 blood clots per 10,000 women per year. Older, more common pill formulations raise that to 5 to 7 per 10,000. Newer formulations push it higher, to 9 to 12 per 10,000.
To put that in perspective, pregnancy itself carries a much higher clot risk: roughly 20 per 10,000 women per year. So while the pill does increase your risk compared to taking nothing, the absolute numbers remain low for most healthy women. The risk is highest in the first year of use, in smokers, and in women over 35. If you have a personal or family history of clotting disorders, this risk becomes more significant.
Stroke Risk Rises With Age
A large Danish registry study found that the extra stroke risk from combined hormonal contraceptives is tiny for younger women: roughly 1 additional ischemic stroke per 100,000 women per year among 18- to 24-year-olds. That number climbs with age. By 40 to 44, it reaches about 16 extra strokes per 100,000, and by 45 to 49, about 24 extra per 100,000. The increase only became statistically significant in women over 40, which is one reason many providers recommend switching to other methods by that age.
Breast and Cervical Cancer
Women currently using oral contraceptives have roughly a 20 to 24% higher risk of breast cancer compared to women who have never used them, based on a National Cancer Institute analysis of more than 150,000 women across 54 studies. That sounds alarming, but the absolute risk depends on your baseline. For a 30-year-old woman, breast cancer is already uncommon, so a 20% increase on a small number is still a small number. Importantly, this elevated risk does not grow with longer use, and it fades after stopping. By 10 years after discontinuation, no increased risk is detectable.
On the other hand, the pill has protective effects against ovarian and endometrial cancer, reducing those risks substantially. The cancer picture is mixed rather than purely negative.
Depression and Mood Changes
The link between hormonal birth control and depression has been debated for years, but large population studies have strengthened the evidence. A cohort study published in Epidemiology and Psychiatric Sciences found that women in the first two years of oral contraceptive use had a 71% higher rate of depression diagnoses compared to women who never used the pill. The effect was even stronger for depressive symptoms broadly: a doubling in rate during those first two years.
Teenagers appear especially vulnerable. Adolescents who started oral contraceptives had a 95% higher rate of depression in the first two years, compared to 74% higher for adults. A separate Swedish study of 900,000 women found increased antidepressant use among adolescent users of various hormonal contraceptives. Even after the initial period, ever having used oral contraceptives was associated with a small but persistent lifetime increase in depression risk (about 5%).
Not everyone will experience mood changes, but if you notice a shift in your mental health after starting hormonal birth control, the data suggests it’s not just in your head.
Bone Density Loss With Injections
The injectable contraceptive (the shot given every three months) stands apart from other methods when it comes to bone health. In a 24-month study of adolescent girls, those receiving the injection lost 1.5% of spine bone density and 5.2% of hip bone density. Meanwhile, girls not on any hormonal method gained bone density during the same period, as you’d expect during adolescence. This is particularly concerning for teens and young adults who are still building peak bone mass. The pill does not appear to have the same effect; in the same study, pill users gained bone density at rates similar to untreated participants.
Gallbladder Problems
Estrogen increases cholesterol concentration in bile, which can promote gallstone formation. A large comparative study found that certain pill formulations raised the risk of gallbladder disease by 10 to 20% compared to older formulations. Pills containing drospirenone showed the highest relative increase. The absolute risk is still modest for most women, but if you already have risk factors for gallstones (such as obesity, rapid weight loss, or a family history), hormonal birth control may add to that risk.
Liver Tumors: Rare but Real
Long-term oral contraceptive use is linked to a rare benign liver tumor called hepatocellular adenoma. The annual incidence among pill users is 30 to 40 cases per million, compared to 1 per million in non-users. Risk climbs with duration: women who used the pill for more than nine years had a 25-fold higher risk compared to those who used it for less than a year. These tumors are not cancer, but they can cause complications if they grow large or rupture, sometimes requiring surgical removal.
Nutrient Depletion
Oral contraceptives have been shown to deplete several key nutrients, including folate, vitamins B2, B6, and B12, vitamins C and E, and the minerals magnesium, selenium, and zinc. For most women eating a varied diet, these shifts may not cause noticeable problems. But for women planning a pregnancy soon after stopping the pill, low folate levels are particularly concerning since folate is critical for preventing neural tube defects in early pregnancy. If you’ve been on the pill for a long time, it’s worth paying attention to these nutrients through diet or supplementation.
Changes in Blood Sugar Regulation
Many hormonal contraceptives cause subtle shifts in how your body handles sugar, including decreased glucose tolerance and increased insulin resistance. These are the same metabolic changes that, over time, raise the risk of type 2 diabetes and cardiovascular disease. The effects vary by formulation and tend to be small in clinical studies, with inconsistent differences between specific progestin types. Progestin-only methods appear to carry less metabolic risk than combined pills, which is why they’re sometimes recommended for women already at risk for diabetes.
What Happens When You Stop
Some women experience a cluster of symptoms after discontinuing hormonal birth control: irregular or missed periods, acne flare-ups, headaches, and mood swings. These are driven by the sudden shift in hormone levels as your body resumes its own hormonal cycling. Not everyone experiences this, and for those who do, symptoms typically resolve within a few months as the body readjusts. Acne can be particularly frustrating because the pill often suppresses it, so stopping can feel like a rebound even though it’s really a return to your pre-pill baseline.
Copper IUD: Different Method, Different Risks
The copper IUD avoids hormonal side effects entirely, but it introduces physical risks. Uterine perforation, where the device pushes through the uterine wall, occurs in about 0.2% of insertions within the first year and 0.6% within five years. Expulsion, where the IUD partially or fully slips out of place, happens in nearly 5% of users within five years. These rates are low, but they’re worth knowing about since a displaced IUD can lose its effectiveness or, in the case of perforation, require a procedure to remove.