Why St. John’s Wort can make birth control less effective
St. John’s Wort can reduce how well hormonal birth control works because it increases activity of liver enzymes that break down hormones. That can lower hormone levels and raise the risk of unintended pregnancy.
What forms of birth control are most affected
This interaction is mainly a concern for hormonal contraceptives that depend on adequate blood hormone levels, including:
- The pill
- The patch
- The vaginal ring
- Birth control implants and hormonal IUDs (risk can vary, but caution is still advised when St. John’s Wort is used)
Barrier methods (like condoms) are not affected in the same way, but they do not replace contraception if hormonal birth control is compromised.
If you already took them together, what should you do?
If you took St. John’s Wort while using hormonal birth control:
- Use condoms (or another non-hormonal method) to reduce pregnancy risk.
- Consider pregnancy testing if your next period is late or abnormal.
- If you had unprotected sex in the past few days, emergency contraception may be an option. (The best choice depends on timing and your situation.)
How to time stopping St. John’s Wort before restarting birth control
Because St. John’s Wort can affect drug metabolism, restarting hormonal birth control immediately after stopping it may still carry risk. A clinician or pharmacist can tell you the safest timing based on the product dose and how your body processes it.
Safer alternatives for anxiety or mild depression
If you’re using St. John’s Wort for mood symptoms, ask a clinician or pharmacist about alternatives that do not interact with hormonal contraception (options depend on your symptoms and health history).
When to get medical advice urgently
Contact a healthcare professional promptly if you:
- Are trying to avoid pregnancy and need reliable contraception now
- Have had breakthrough bleeding while using St. John’s Wort
- Took St. John’s Wort and had unprotected sex and are considering emergency contraception
Sources
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