Morning-After Pill & Back Pain: Side Effects & What to Expect

Emergency contraception (levonorgestrel 1.5 mg "Plan B" or ulipristal acetate "ella") can cause side effects, including back pain, though it's less commonly reported than others.

Common Side Effects (Levonorgestrel)

• Nausea (14–23%), vomiting (5–6%) — take with food; if vomit <2h, repeat dose.
• Fatigue, headache, dizziness.
• Breast tenderness.
• Lower abdominal/pelvic pain (often crampy) — reported in ~10–15%.
• Back pain — likely referred from uterine cramping or prostaglandin effects; usually mild, transient.
• Menstrual changes: earlier/later period, heavier/lighter flow, spotting.

Ulipristal Acetate (Ella) Specifics

• Similar profile; may be more effective up to 120h (5 days) post-intercourse.
• Can delay ovulation more reliably, especially near LH surge.
• Not recommended if breastfeeding (pump/dump 1 week).

When to Seek Medical Attention

• Severe abdominal/pelvic pain (rule out ectopic pregnancy).
• Heavy bleeding (soaking >1 pad/hr).
• Persistent vomiting >24h.
• Signs of allergic reaction (rash, swelling, difficulty breathing).
• Period >1 week late → pregnancy test.

Key Points

• EC is not an abortifacient — prevents ovulation/fertilization; does not disrupt established pregnancy.
• Effectiveness: 75–89% (LNG) if taken ≤72h; 85% (UPA) ≤120h. Sooner = better.
• Not for regular contraception — use ongoing method (IUD, implant, pill, condoms).
• Copper IUD inserted ≤5 days post-intercourse is most effective EC (>99%) + ongoing contraception.

Back pain from EC is usually mild and self-limited. If severe or accompanied by red flags, seek care promptly.