HCG stands for human chorionic gonadotropin, and is known as ‘the pregnancy hormone.’  HCG is formed by trophoblastic cells in the embryo (pregnancy).  These cells occupy the uterine lining and build up into the placenta.

What essential work is done by HCG in the pregnancy?

HCG stimulates the ovary to make progesterone.  Progesterone is the hormone that maintains the endometrial lining of the uterus for carrying the pregnancy.  In the normal menstrual cycle, progesterone made by the ovary only lasts for 2-weeks after ovulation.  After 2-weeks, the progesterone level falls and menstruation begins.  However, if pregnancy occurs, HCG stimulates the ovaries to produce progesterone to prevent menstrual bleeding.

Early pregnancy monitoring after tubal ligation reversal through HCG

Pregnancy tests perceive HCG.  Urine pregnancy tests typically can identify HCG within 14-16 days after ovulation.  Blood pregnancy tests are more receptive for a positive pregnancy and can perceive HCG within 10-12 days after ovulation.

Quantitative tests for HCG

Whether urine or blood tests, are those that actually measure the HCG in the blood stream.  When women become pregnant after tubal ligation reversal surgery, quantitative HCG assays should be performed as soon as a positive home pregnancy test (a qualitative test) is positive.  Once the quantitative serum HCG levels reaches 1500-2000 mIU/ml, a vaginal ultrasound should be able to identify a gestation sac within the uterus.

HCG doubling time

In a normally developing pregnancy, quantitative serum HCG levels increase twofold every 2-3 days during the initial weeks of pregnancy. Repeating HCG tests after a tubal reversal surgery can help indentify normal pregnancies versus ectopic or abnormal pregnancies.