*Human Chorionic Gonadotropin*
The hormone human chorionic gonadotropin (better known as hCG) is produced during pregnancy. It is made by cells that form the placenta, which nourishes the egg after it
has been fertilized and becomes attached to the uterine wall. Levels can first be detected by a blood test about 11 days after conception and about 12 - 14 days after
conception by a urine test. In general the hCG levels will double every 72 hours. The level will reach its peak in the first 8 – 11 weeks of pregnancy and then will decline and
level off for the remainder of the pregnancy.
In a bout 85% of normal pregnancies, the hCG level will double every 48 – 72 hours. As you get further along in pregnancy and the hCG level gets higher, the time it takes to
double can increase to about every 96 hours.
Caution must be used in making too much of hCG numbers. A normal pregnancy may have low hCG levels and result in a perfectly healthy baby. The results from an
ultrasound after 5 - 6 weeks gestation are much more accurate than using hCG numbers.
An hCG level of less than 5mIU/ml is considered negative for pregnancy, and anything above 25mIU/ml is considered positive for pregnancy.
The hCG hormone is measured in milli-international units per milliliter (mIU/ml).
A transvaginal ultrasound should be able to show at least a gestational sac once the hCG levels have reached between 1,000 – 2,000mIU/ml. Because levels can
differentiate so much and conception dating can be wrong, a diagnosis should not be made by ultrasound findings until the hCG level has reached at least 2,000.
A single hCG reading is not enough information for most diagnoses. When there is a question regarding the health of the pregnancy, multiple testings of hCG done a couple
of days apart give a more accurate assessment of the situation.
The hCG levels should not be used to date a pregnancy since these numbers can vary so widely.
There are two common types of hCG tests. A qualitative hCG test detects if hCG is present in the blood. A quantitative hCG test (or beta hCG) measures the amount of
hCG actually present in the blood.
It is not common for doctors to routinely check your hCG levels unless you are showing signs of a possible problem. A health care provider may recheck your levels if you
are bleeding, experiencing severe cramping, or have a history of miscarriage.
Most women can expect their levels to return to a non-pregnant range about 4 – 6 weeks after a
pregnancy loss has occurred. This can differentiate by how the loss occurred (spontaneous miscarriage, D & C procedure, abortion, natural delivery) and how high the levels
were at the time of the loss.
Health care providers usually will continue to test hCG levels after a pregnancy loss to ensure they return back to <5.0 Nothing should interfere
with an hCG level except medications that contain hCG. These medications are often used in fertility treatments, and your health care provider should advise you on how
they may affect a test. All other medications such as antibiotics, pain relievers, contraception or other hormone medications should not have any effect on a test that
-HCG in urine
This type of human chorionic gonadotropin (HCG) test measures the specific level of HCG in the urine. HCG is a hormone produced in the body during pregnancy.
To collect a urine sample, you urinate into a special (sterile) cup. Home pregnancy tests require the test strip to be dipped into the urine sample or passed through the urine
stream while urinating. Carefully follow package directions. Usually a first-morning sample (the first time you urinate in the morning) is best.
This is because urine is the
most concentrated and has enough HCG to be detected.
Urine HCG tests are a common method of determining if a woman is pregnant. The best time to test for pregnancy at home is after you miss your period.
The test is negative if you are not pregnant.
The test is positive if you are pregnant.
A pregnancy test, including a properly performed home pregnancy test, is considered to be about 98% accurate. Positive results are more likely to be accurate than
negative results. When the test is negative but pregnancy is still suspected, the test should be repeated in 1 week.