The Pregnancy Hormone Human Chorionic Gonadotropin

November 12, 2012

The Pregnancy Hormone Human Chorionic Gonadotropin

The hormone that marks the beginning of pregnancy is human Chorionic Gonadotropin (hCG). This is the hormone that you test for with the over-the-counter pregnancy tests and begins to appear 12 to 14 days after your egg is fertilized. The levels of hCG will double thereafter every 72 hours and will reach its peak somewhere between the 8


and 11


week of gestation and then begin to decline and level off. There are some things that are important to know about fluctuations in hCG levels during the process of pregnancy.

  • During a normal pregnancy, hCG levels generally double every 48-72 hours initially

  • It is possible to have low hCG levels and still have a normal pregnancy

  • hCG levels below 5mIU/ml indicates no pregnancy and anything above 25mIU/ml is considered positive for pregnancy

  • hCG levels are measured in milli-International Units per milliliter (mIU/ml)

  • An ultrasound should show a gestational sac when hCG levels are between 1,000 to 2,000 mIU/ml

  • If the health of a pregnancy is in question, multiple testings of hCG need to be done several days apart as hCG levels can vary greatly

  • hCG levels can not be used to date a pregnancy because their numbers can vary greatly

It is important to know that there are two types of hCG tests available. One is known as a qualitative hCG test and simply detects whether hCG is present in the blood. The second test is known as a quantitative hCG test (beta hCG) which measures the actual concentration in the blood. The actual levels of hCG in blood is not as important as the relative change in hCG levels. Expectant mothers often ask questions about hCG levels and how that relates to the well being of their pregnancy. Common questions include: what does it mean if I have a low hCG level, what does it mean if I have a high hCG level, should I have my hCG levels checked regularly, what will my hCG levels be if I lose my pregnancy, and can anything interfere with my hCG levels.

It’s not unusual for a an expectant mom to be concerned about low levels of hCG. These levels should be rechecked within 2 days or so to see what’s happening. Nevertheless, you may have miscalculated conception, or it could be due to an ectopic pregnancy or possible miscarriage. On the other hand, you could have what appears to be a high level of hCG. Again, you should recheck your levels within a couple of days and look at the difference in hCG levels not the actual level. Again, you may have miscalculated conception, you may have multiple pregnancies or a molar pregnancy. A molar pregnancy is when a fertilized egg becomes an abnormal growth of tissue and the pregnancy is not viable.

Expectant mothers often wonder if their hCG levels should be checked often. Generally, your physician will not do so unless he/she suspects something is wrong. If you present with bleeding, have cramping or have a history of miscarriage your physician may check periodically.

If for some reason a pregnancy is lost, it is nice to know what will happen to your hCG levels. The general rule is that after a pregnancy, hCG levels will return to normal in somewhere between 4-6 weeks. And, in fact the length of time can indicate how the loss occurred. For example, whether you had a spontaneous abortion, natural delivery or perhaps a D & C procedure.

Another common question about hCG levels is can anything affect my hCG levels such as medications, antibiotics, NSAIDS, birth control or perhaps other hormone medications you might be taking. It appears to be the consensus that nothing will affect your hCG levels except for medications that contain hCG and these medications are often used for fertility treatments. Your healthcare provider will let you know how that works.

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