Spotting on Birth Control: Breakthrough Bleeding vs. Implantation

Spotting One Week Before Expected Period on the Pill

Birth control pills are >99% effective with perfect use, ~91% with typical use. Pregnancy is possible but unlikely. Spotting can have several causes:

1. Breakthrough Bleeding (Most Common)

• Light, unscheduled bleeding during active pill weeks.
• Caused by hormone fluctuations, missed pills, new pack start, or individual sensitivity.
• Usually resolves in 1–3 months; not dangerous.

2. Implantation Bleeding (Rare on Pill)

• Very light spotting 6–12 days after ovulation (if ovulation occurred despite pill).
• Pink/brown, lasts hours to 2 days; no clots.
• Less likely than breakthrough bleeding.

3. Other Causes

• Cervical irritation (exam, intercourse)
• STI (chlamydia, gonorrhea)
• Pill interaction (antibiotics, anticonvulsants, St. John's wort)
• Early pregnancy loss

What to Do

1. Continue taking pills as scheduled.
2. Take a home pregnancy test (accurate ~14 days after potential conception).
3. If positive → contact provider immediately.
4. If negative but spotting persists >3 months or is heavy/painful → see clinician for evaluation.