hCG Levels: Normal Ranges Week by Week
A reference guide to normal hCG levels by week of pregnancy, how the hormone rises, and when single numbers are less useful than trends.
Table of Contents
- How hCG Rises in Early Pregnancy
- Why Trends Matter More Than Single Numbers
- Frequently Asked Questions
How hCG Rises in Early Pregnancy
Human chorionic gonadotropin (hCG) is the hormone detected by pregnancy tests. It is produced by the cells that become the placenta and roughly doubles every 48 to 72 hours in a healthy early pregnancy. Levels are measured in international units per litre (IU/L). At around 4 weeks (from the first day of your last period) hCG may be as low as 5 to 50 IU/L. By 6 weeks it typically ranges from 1,000 to 30,000 IU/L, and by 8 to 12 weeks it peaks between around 7,000 and 230,000 IU/L before gradually declining. Because the range is so wide, a single reading is rarely meaningful on its own.
Why Trends Matter More Than Single Numbers
Two hCG blood tests taken 48 hours apart are far more useful than one. A rising level that roughly doubles suggests a developing pregnancy. A level that falls or rises very slowly may indicate a non-viable pregnancy or ectopic pregnancy. After about 6 to 7 weeks, an ultrasound is a better guide than hCG because a heartbeat can be seen. Many private clinics offer serial hCG testing for reassurance, but the NHS usually relies on a single early test followed by a scan if there are concerns.
Frequently Asked Questions
What is a normal hCG level at 5 weeks?
At 5 weeks from your last period, hCG typically ranges from around 18 to 7,000 IU/L. The range is very wide, so a single number cannot confirm whether the pregnancy is healthy.
Do high hCG levels mean twins?
Twin pregnancies often produce higher hCG, but a single high reading is not diagnostic. Only an ultrasound can confirm twins, usually from around 6 to 7 weeks.
When does hCG stop rising?
hCG usually peaks between 8 and 12 weeks and then gradually falls, settling at a lower level for the rest of pregnancy. This is why first-trimester symptoms such as nausea often improve after week 12.
This information is for educational purposes only and is not a substitute for professional medical advice. Always consult your midwife, GP, or obstetrician about your individual results and care plan.
Further reading:
Related articles: Early Pregnancy Blood Tests | hCG Levels Explained | Anaemia in Pregnancy