Pregnancy
Pregnancy triggers a series of hormonal changes in the body, beginning with a rise in human chorionic gonadotrophin (hCG). This hormone is produced by the developing placenta shortly after the fertilised egg implants in the uterine wall.
Beta hCG can be detected in the blood before a missed period, often as early as 10 days after conception. Blood tests for beta hCG are more sensitive than urine-based pregnancy tests and can also provide quantitative results, which may be useful in monitoring early pregnancy progression.
Early signs of pregnancy may include a missed period, nausea, breast tenderness, fatigue and more frequent urination. Beta hCG is also used as a tumour marker in certain cancers, including testicular and some ovarian cancers, so elevated levels do not always indicate pregnancy.
Causes of Pregnancy
Elevated beta hCG levels are most commonly caused by pregnancy. After a fertilised egg implants in the uterine wall, the developing placenta begins producing hCG. Levels rise rapidly in early pregnancy, typically doubling every 48 to 72 hours during the first weeks.
Other causes of elevated beta hCG include:
- Ectopic pregnancy, where the fertilised egg implants outside the uterus (usually in a fallopian tube). hCG levels may rise more slowly than expected
- Miscarriage, where hCG may initially be elevated but fails to rise normally or begins to decline
- Molar pregnancy (gestational trophoblastic disease), a rare condition in which abnormal tissue grows in the uterus instead of a normal embryo
- Certain cancers, including testicular germ cell tumours and some ovarian cancers, which can produce hCG
In non-pregnant individuals, a significantly raised beta hCG level warrants further investigation to identify the underlying cause.
Tests that can help check this condition
Learn more on the official NHS page .
