hCG Calculator
Enter the required values below to run the educational estimation.
The Role of hCG in Early Pregnancy
Human Chorionic Gonadotropin (hCG) is the hormone produced by syncytiotrophoblast cells in the early placenta. It signals the corpus luteum to continue progesterone production, maintaining the uterine lining to support fetal development.
Calculating Your hCG Doubling Time
This calculator determines the rate of hCG increase by comparing two quantitative hCG levels taken at least 24 hours apart. The formula uses natural logarithms to identify the exact hours it takes for the concentration to double.
Why Doubling Rates Slow Down
As pregnancy progresses, hCG doubling times naturally slow down. After levels exceed 6,000 mIU/mL, the doubling rate is no longer a reliable indicator of fetal health, and clinical providers shift to ultrasound scans to evaluate pregnancy viability.
When to Seek Urgent Medical Attention
- Severe, sharp pelvic or abdominal pain (ectopic risk).
- Moderate to heavy vaginal bleeding or tissue passage.
- Severe dizziness, fainting, or shoulder pain.
Frequently Asked Questions
For hCG levels under 1,200 mIU/mL, the hormone typically doubles every 48 to 72 hours. Between 1,200 and 6,000 mIU/mL, doubling slow to 72 to 96 hours.
Slower doubling rates can indicate a non-viable pregnancy, impending miscarriage, or ectopic pregnancy. However, they must always be interpreted by a physician using ultrasound.
