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What are Beta hCG Levels?

Erin J. Hill
Erin J. Hill

Beta human chorionic gonadotropin (hCG) testing refers to a blood test that can read the exact levels of hCG in a woman's blood. This can also be called a quantitative hCG test, and it is the most accurate test available for detecting pregnancy in its earliest stages. By comparison, urine pregnancy tests and and qualitative blood tests only detect the presence of hCG, but they are generally not sensitive enough to read levels below a certain amount. Beta hCG levels are therefore highly recommended for verifying a pregnancy as early as possible, and for checking on the health of a known pregnancy by ensuring that the readings of hCG are normal.

HCG is a hormone produced by cells which will become the placenta and is needed to alert the body that a pregnancy has occurred. This tells the brain and ovaries not to secrete additional hormones to bring about a monthly menstrual period, but to instead begin supplying hormones to support the pregnancy and its needs. Beta hCG levels should be able to predict a pregnancy within a day or two of implantation, which generally occurs four to seven days after conception. Implantation is when the group of cells which will become the baby, placenta, and yolk sac embed into the lining of the uterus.

The exact beta hCG levels will vary widely from woman to woman and from pregnancy to pregnancy.
The exact beta hCG levels will vary widely from woman to woman and from pregnancy to pregnancy.

The exact beta hCG levels will vary widely from woman to woman and from pregnancy to pregnancy. For this reason, hCG levels should not be used to determine the gestational age of the embryo or to determine a pregnancy's viability unless being compared to previous results. In most cases, as long as beta hCG levels are going up and doubling approximately every 48 hours, the pregnancy is considered viable. If levels go down or stay the same, this could indicate an early miscarriage.

HCG tells the brain and ovaries not to secrete additional hormones that would bring about a woman's monthly menstrual period.
HCG tells the brain and ovaries not to secrete additional hormones that would bring about a woman's monthly menstrual period.

Doctors do not normally perform routine tests to check beta hCG levels in detected pregnancies unless a problem is suspected. Issues that warrant testing may include vaginal bleeding, severe cramping, or a past miscarriage in the mother. Tests may be taken to get hCG levels and then taken again two days later to ensure that the hormone levels are increasing at the appropriate rate. It should be noted, however, that in some cases hCG levels rise more quickly or slowly, even in healthy pregnancies. If beta hCG levels are rising at a slower than average rate, a trans-vaginal ultrasound may be the best way to determine whether or not the pregnancy is viable.

Discussion Comments

OeKc05

My friend was a few weeks along when she experienced vaginal bleeding and cramps. She knew this was not normal, so she visited her doctor.

He tested her beta hCG levels and saw that they had gone down significantly from her last visit. So far, the fetus was still present, but the drop in hCG was not a good sign.

A few days later, she did have a miscarriage. Her doctor told her that her hCG levels had dropped to zero.

ElizaBennett

@dfoster85 - So glad your friend's story has a happy ending! I've heard that about multiple pregnancies. They say that's why women carrying multiples often seem to be sicker. A lady I worked with was crazy sick in the first few weeks - so sick she had to 'fess up to her coworkers before she even saw the doctor. They teased her she was having twins, but she was sure she was just feel the effects of one.

Turns out they were right! (I think they were as surprised as she was!) Of course, I never needed more than one to make me sick as a dog.

dfoster85

An interesting tidbit is that hCG pregnancy levels rise faster if you have more than one baby in there. I guess they are more likely to notice this if you've had fertility treatment, since in a "normal" pregnancy you don't go to the doctor until about eight weeks and then they can see all the babies on the ultrasound.

A friend of mine had IVF. They would do the beta hCG test after each cycle and it was such a roller coaster for her; one month there was nothing, another they detected a pregnancy but then her next test showed the level staying the same instead of rising. (She miscarried, but it was so early that if she hadn't been having IVF, she would never have known she was pregnant.)

Then the next cycle, she had the test and it showed something. Two days later, it had well more than doubled. That was the first clue that there were two in there!

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    • The exact beta hCG levels will vary widely from woman to woman and from pregnancy to pregnancy.
      By: Valua Vitaly
      The exact beta hCG levels will vary widely from woman to woman and from pregnancy to pregnancy.
    • HCG tells the brain and ovaries not to secrete additional hormones that would bring about a woman's monthly menstrual period.
      By: lukasmajercik
      HCG tells the brain and ovaries not to secrete additional hormones that would bring about a woman's monthly menstrual period.
    • Miscarriage may occur if hCG levels go down or stay the same.
      By: fasphotographic
      Miscarriage may occur if hCG levels go down or stay the same.
    • Beta hCG levels should be able to predict a pregnancy within a day or two of implantation.
      By: Monkey Business
      Beta hCG levels should be able to predict a pregnancy within a day or two of implantation.
    • Vaginal ultrasound probes may be inserted into the vagina to obtain an image of the uterus.
      By: zayacsk
      Vaginal ultrasound probes may be inserted into the vagina to obtain an image of the uterus.
    • HcG levels should generally not be used to determine the viability of a pregnancy.
      By: Langstrup
      HcG levels should generally not be used to determine the viability of a pregnancy.