In early pregnancy, how often can HCG levels double?

• A. They decrease daily
• B. They stay constant
• C. They can double every day up to 10 weeks
• D. They double every week

Answer: (C)

In early pregnancy, hCG rises very quickly as the placenta begins to form and support the developing fetus. Because this hormone is needed to maintain the pregnancy, serial hCG measurements often show a rapid increase. The pattern most consistent with a normal early pregnancy is a rapid rise, commonly described as doubling on a daily basis, continuing this brisk increase up to about 10 weeks of gestation. After around 8–10 weeks, the rate of rise slows and the pattern changes as the pregnancy progresses.

This makes sense clinically: a rapidly increasing hCG supports the idea of a viable pregnancy, whereas a decrease, a constant level, or a much slower (weekly) increase would be less consistent with early viability.