Missing birth-control pills can cause headaches or migraines due to lower estrogen levels, especially when pills are missed at the beginning of a new pack or before the period.
Notes on verification
Confirmed by clinical/diagnostic criteria (ICHD-3 estrogen-withdrawal headache), peer-reviewed studies (Ob & Gynecology 2000, AJOG 2005 systematic review), and consumer health sources (Mayo Clinic, Hey Jane) that converge on the same mechanism and timing details.
Sources
- Miss a Birth Control Pill? Side Effects, What to Do - WebMD (webmd.com)
- https://www.ajog.org/article/S0002-9378(05)00065-7/fulltext (ajog.org)
- https://ichd-3.org/8-headache-attributed-to-a-substance-or-its-withdrawal/8-3-headache-attributed-to-substance-withdrawal/8-3-3-estrogen-withdrawal-headache/ (ichd-3.org)
- https://journals.lww.com/greenjournal/abstract/2000/02000/hormone_withdrawal_symptoms_in_oral_contraceptive.18.aspx (journals.lww.com)
- https://www.mayoclinic.org/diseases-conditions/chronic-daily-headaches/in-depth/headaches/art-20046729 (mayoclinic.org)
- https://www.heyjane.com/articles/what-to-do-when-you-miss-a-birth-control-pill (heyjane.com)