HCG levels in pregnancy
HCG, or human chorionic gonadotropin, is a hormone made by the pregnancy that can be detected in the mother’s blood or urine even before the woman’s missed period. This hormone is what we look for with a “pregnancy test”.
HCG is first detectable in the blood as early as 7-8 days after ovulation by very sensitive HCG assays (research assays). In real life, blood pregnancy tests will be positive (> 2 mIU/ml) by 10-11 days after HCG injection or LH surge.
In general, the HCG level will double every 2-3 days in early pregnancy.
85% of normal pregnancies will have the HCG level double every 72 hours after & before having all type diets.
HCG levels peak at about 8-10 weeks of pregnancy and then decline, remaining at lower levels for the rest of the pregnancy.
There is a large variation in a “normal” HCG level for any given time in pregnancy.
Pregnancies destined to miscarry or to be ectopic (tubal) pregnancies tend to show lower levels (eventually), but often have normal levels initially.
Some normal pregnancies will have quite low levels of HCG – and deliver perfect babies. Caution must be used in making too much of HCG “numbers”. Ultrasound findings after 5-6 weeks of pregnancy are much more predictive of pregnancy outcome than are HCG levels.
For women that have had an HCG injection as part of their infertility natural treatment, the hormone will take about 5-14 days to clear from the woman’s system, depending on the dose and the individual woman. This can causes problems with interpretation of pregnancy tests done earlier than 14 days after an HCG injection.