What are the side effects of hormonal birth control?

Bottom lineHormonal birth control is safe but can cause mostly mild side effects that settle within 2 to 3 months, including irregular bleeding, nausea, breast tenderness, headaches, mood changes, and libido shifts; benefits include lighter, more regular periods and help with acne, PMS, endometriosis, and PCOS/PMOS. Estrogen-containing methods carry a small increased clot risk (higher with smoking over 35, migraine with aura, or clot history), so see a doctor for side effects that don't settle or clot warning signs.

Hormonal birth control is safe and well-studied, but it can cause side effects, most of which are mild and settle within 2 to 3 months as your body adjusts.

Common, usually temporary side effects

• Irregular bleeding or spotting (especially early on)
• Nausea
• Breast tenderness
• Headaches
• Mood changes
• Changes in libido
• Bloating or slight weight changes (evidence for major weight gain is weak)

These often improve after a few months or by switching methods.

Benefits to weigh against side effects

• Lighter, more regular, less painful periods
• Help with acne, PMS, and PMDD
• Lower risk of ovarian and endometrial cancers
• Management of endometriosis and PCOS/PMOS symptoms

Less common but serious risks (mainly estrogen-containing methods)

• Blood clots - a small increased risk, higher if you smoke and are over 35, have migraine with aura, or a clot history
• This is why a clinician screens for these before prescribing the combined pill

When to see a doctor

• Side effects that don't settle after a few months
• Warning signs of a clot: severe leg pain/swelling, chest pain, breathlessness, sudden severe headache or vision changes (seek urgent care)
• New migraine with aura on a combined method

Switching type or method often resolves side effects.

See combined pill vs mini pill.

Femora helps you track side effects and bleeding so you can decide whether a method suits you.