Implantation Bleeding: Timing, Appearance, and Differential Diagnosis

Implantation bleeding occurs when the blastocyst attaches to the endometrium, 6–12 days after conception (typically day 9).

Characteristics

• Flow: Very light — spotting, few drops.
• Color: Pink, brown (old blood), not bright red.
• Duration: Hours to 1–2 days.
• Timing: Before expected period (often 2–7 days early).
• Symptoms: Mild cramping possible; no clots.

Differential Diagnosis for Early Spotting

• Ovulation Spotting: Mid-cycle, brief, clear/pink.
• Menstrual Irregularity: Hormonal fluctuation.
• Cervical/Endometrial Polyps/Fibroids: Intermenstrual bleeding.
• STIs: Cervicitis (chlamydia, gonorrhea).
• Endometriosis/Adenomyosis: Spotting, pain.
• Hormonal Contraception: Breakthrough bleeding.

If pregnancy test negative but spotting persists, or if pregnant with bleeding, consult a clinician. Serial hCG and ultrasound confirm viable intrauterine pregnancy.