by Human Chorionic Gonadotropin, commonly known as HCG, is a critical hormone that plays a key role during pregnancy. In this article, we will explore what HCG is, its functions in the body, clinical uses, and more.
What is HCG?
HCG, also known as the pregnancy hormone, is a glycoprotein hormone that is made by the developing embryo shortly after fertilization and the following implantation in the uterine wall. The primary function of HCG is to support the early stages of pregnancy by stimulating progesterone production and maintaining the functional life of the corpus luteum in the ovary.
The placenta takes over progesterone production at about 12 weeks of gestation, at which point HCG levels start to fall. HCG continues to be produced until the end of the first trimester and maintains low levels throughout pregnancy.
Functions of HCG
Some of the key functions of HCG during pregnancy include:
– Maintenance of the Corpus Luteum: Right after fertilization occurs, HCG signals the corpus luteum, a structure in the ovary, to continue producing progesterone. Progesterone prepares the uterus for reception of the fertilized egg and sustains early pregnancy until the placenta is formed.
– Promotion of Progesterone Production: HCG stimulates the corpus luteum to secrete progesterone, which thickens the lining of the uterus and inhibits it from shedding. This allows implantation of the fertilized egg to occur.
– Prevention of Menstruation: By maintaining progesterone levels, HCG prevents menstruation and the sloughing of the uterine lining, thus promoting implantation and continuation of pregnancy.
– Nourishment of the Embryo: HCG sustains very early embryonic development prior to implantation by supporting progesterone secretion until the placenta develops fully.
Clinical Uses of Measuring HCG Levels
Given its critical role in pregnancy, measuring HCG levels in the blood or urine has important clinical applications:
Pregnancy Testing
Home pregnancy tests detect the presence of HCG in urine to determine if a woman is pregnant. HCG can be detected in the blood and urine as soon as 1-2 weeks after conception.
Confirming and Dating Pregnancy
Doctor’s often order a quantitative HCG blood test to confirm pregnancy and get an idea of gestational age based on expected HCG doubling times in early pregnancy. Serial HCG tests can detect abnormal rises that may signal an ectopic or molar pregnancy.
Diagnosing Miscarriage
If bleeding or pain occurs, measuring HCG levels helps determine if the pregnancy is still viable – continuing rises point to a normal intrauterine pregnancy while falling or unchanged levels may indicate an incomplete miscarriage.
Fertility and Ovulation Testing
Some fertility specialists use HCG blood tests to confirm ovulation after fertility treatments like Clomid or Letrozole. A post-treatment rise in HCG signals successful ovulation occurred.
Assessing Gestational Trophoblastic Disease
Diseases like hydatidform moles or choriocarcinoma produce abnormally high HCG levels, so monitoring this hormone helps diagnose and manage these rare placental tumors.
HCG Levels Through Early Pregnancy
As the pregnancy progresses there are expected changes in HCG levels:
– At the time of a missed period, HCG is around 5-50 mIU/mL (international units per milliliter)
– It doubles every 1-2 days early on, with levels around 1,080-7,860 mIU/mL by the time of the first ultrasound around 6 weeks
– Peak between 9-11 weeks of gestation at around 56,500-229,000 mIU/mL
– Fall to 6,530-25,080 mIU/mL at 14 weeks as placenta takes over hormone production
– Continue to decline through term, becoming undetectable postpartum
Any abnormal deviation from the normal rising and falling pattern may warrant medical attention.
Additional Uses of HCG
In addition to its roles in pregnancy, HCG has some other important uses:
– Male Fertility – Low dose HCG injections are sometimes used alongside clomiphene or anastrozole to stimulate testosterone production in males with low testosterone levels.
– Weight Loss – Due to its fat mobilizing effects, some take unsupported HCG injections or homeopathic preparations for weight loss, despite minimal evidence of safety or efficacy.
– Performance Enhancement – HCG is misused by bodybuilders at the end of steroid cycles to encourage recovery of natural testosterone production. However, this unregulated use poses health risks.
In summary, human chorionic gonadotropin plays a pivotal role in the success of early pregnancy through its impact on ovarian hormone levels and embryonic development. Measuring HCG is crucial for fertility, pregnancy confirmation and monitoring, and diagnosing certain reproductive disorders. Further research continues to better understand its functions and therapeutic potential.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
