Bleeding in Early Pregnancy: Differential Diagnosis and Urgent Red Flags

Common Causes

Diagnosis	Timing	Key Features	Urgency
Implantation bleeding	4–5 weeks (10–14 days post-conception)	Light spotting, pink/brown, <24–48 hrs, no pain	Benign
Threatened miscarriage	<20 weeks	Vaginal bleeding ± cramping; closed cervix; viable fetus on US	Urgent eval
Inevitable/incomplete miscarriage	<20 weeks	Heavy bleeding, open cervix, tissue passage	Emergent
Ectopic pregnancy	6–10 weeks	Unilateral pain, bleeding, +β-hCG, no IUP on US	Emergency
Molar pregnancy	8–12 weeks	Bleeding, hyperemesis, uterus large for dates, high β-hCG, "snowstorm" US	Urgent
Subchorionic hematoma	7–12 weeks	Bleeding, US shows crescentic fluid collection	Monitor
Cervical causes	Any time	Post-coital, friable cervix, polyp, cervicitis	Routine

Immediate Steps

1. Call your OB/GYN immediately for any bleeding in pregnancy.
2. Quantify: pads per hour, clot size, color.
3. Note associated symptoms: pain (location, severity), dizziness, shoulder tip pain (referred from hemoperitoneum).
4. Do not use tampons; avoid intercourse.

Diagnostic Workup

• Quantitative β-hCG (trend: should double every 48 hrs in early viable IUP).
• Transvaginal ultrasound: confirm intrauterine pregnancy, fetal cardiac activity, evaluate adnexa.
• Rh typing: if Rh-negative, give RhIg (RhoGAM) within 72 hrs of bleeding.

When to Call 911 / Go to ER

• Heavy bleeding (soaking >1 pad/hr for 2 hrs)
• Severe pain, syncope, shoulder pain
• Signs of hemodynamic instability
• Passing tissue (save for pathology if possible)