What Is Beta-hCG?
Human chorionic gonadotropin (hCG) is a hormone produced by the placenta after a fertilised egg implants in the uterus. A blood test measures the beta subunit of hCG for high sensitivity — it can detect pregnancy as early as 8–10 days after conception.
Normal hCG Levels by Week of Pregnancy
| Week of Pregnancy (from LMP) | Normal hCG Range (mIU/mL) |
|---|---|
| 3 weeks | 5–50 |
| 4 weeks | 5–426 |
| 5 weeks | 18–7,340 |
| 6 weeks | 1,080–56,500 |
| 7–8 weeks | 7,650–229,000 |
| 9–12 weeks | 25,700–288,000 |
| 13–16 weeks | 13,300–254,000 |
| 17–24 weeks | 4,060–165,400 |
| 25–40 weeks | 3,640–117,000 |
What a Low hCG Means
- Miscarriage or threatened miscarriage
- Ectopic pregnancy (embryo outside the uterus) — urgent investigation needed
- Inaccurate dating of pregnancy
What a High hCG Means
- Multiple pregnancy (twins, triplets)
- Molar pregnancy (gestational trophoblastic disease)
- Some cancers (testicular, ovarian) use hCG as a tumour marker
Urgent: Ectopic PregnancyLow or slowly rising hCG with pelvic pain and/or bleeding requires urgent ultrasound to rule out ectopic pregnancy — a medical emergency.
FAQs
How is a blood hCG different from a urine pregnancy test?
Blood hCG (quantitative) gives an exact number and detects pregnancy earlier. Urine tests only give positive/negative.
Does hCG need to double exactly?
Generally hCG should rise at least 53–66% every 48 hours in early viable pregnancy. Serial measurements matter more than a single value.
When does hCG peak?
Around 10–12 weeks of pregnancy, then gradually declines.
Medical Disclaimer: hCG levels vary widely between individuals. Interpret with ultrasound and clinical assessment by your doctor or obstetrician.