Beta HCG: What Is It and What Should Its Levels Be?

After conception (when a sperm fertilizes an egg), the developing placenta begins to produce and release HCG.

Human chorionic gonadotropin (HCG) is a chemical typically created by tissue found in early embryos, which eventually becomes part of the placenta. Measuring HCG levels can assist in determining pregnancy and also provide useful information following a miscarriage. Additionally, measuring HCG is beneficial not only for pregnancy but also in various cancers, including choriocarcinoma and some extragonadal malignancies.

What Is Beta HCG?

A pregnancy test is based on detecting HCG in urine or blood. If HCG results are interpreted as positive, it indicates the presence of pregnancy, while a negative result indicates there is no pregnancy. However, beta HCG not only shows whether the hormone is present in the blood but also the exact amount.

The Beta-HCG test can be conducted during an early prenatal doctor visit to confirm pregnancy.

In addition, over-the-counter pregnancy tests detect HCG in urine to diagnose pregnancy. However, in routine pregnancies, beta HCG is not always performed or necessary. In the early stages of pregnancy, the rate at which HCG levels increase over time is more indicative than the actual amount of the hormone in the blood. Slowly rising HCG levels may indicate a higher risk of miscarriage. For those undergoing fertility treatments, the doctor may request a beta-HCG test just before or around the time of menstruation to determine if the treatment was successful.

How Is a Beta HCG Test Done?

Both serum and urine tests are available for HCG. The serum test is much more sensitive and specific than the urine test. However, the urine test offers patients comfort and a quick turnaround. The quantitative test measures the level of HCG hormone in a blood sample. A vein is located, the skin around it is cleaned with alcohol, and pressure is applied with cotton or gauze, then secured with a bandage. The person may feel a brief sting or pinch when the needle is inserted, or may feel nothing at all. No special preparation is needed for the HCG blood test.

To collect a urine sample, urine is gathered in a special (sterile) cup. The analysis is then conducted on this urine. In most cases, a urine sample collected first thing in the morning is ideal, as this is when urine is most concentrated and likely to contain detectable HCG levels. At-home pregnancy tests require either dipping the test strip into the urine sample or holding it in the urine stream while urinating.

What Is High Beta HCG?

Beta-HCG levels are low in the early stages of pregnancy and increase throughout the first trimester (first 3 months) and into the second trimester (second 3 months). High HCG levels may indicate that a woman is pregnant with twins or triplets, though only an ultrasound can confirm this. Sometimes, above-average HCG levels suggest a higher likelihood of Down syndrome. A high HCG level can also indicate other conditions and may need to be rechecked in 48-72 hours to assess any changes. A high level may indicate:

• Incorrect pregnancy dating
• Multiple pregnancies
• Uterine cyst
• Ovarian cancer
• Preeclampsia

What Is Low Beta HCG?

A low HCG level can indicate various conditions, and it should be rechecked within 48-72 hours to observe how the level changes. It is normal for tests performed in the first month of pregnancy to show low results. Similarly, low HCG levels can also be seen in the second and third trimesters. However, a drop in HCG levels during the second and third months of the first trimester can be caused by several factors. Low levels may indicate:

• Incorrect calculation of pregnancy dating
• Potential miscarriage
• Fetal death
• Incomplete miscarriage
• False negativity
• Ectopic pregnancy

Factors Affecting Beta HCG Levels

A person with a positive test result is likely pregnant. However, there are certain conditions, such as specific types of cancer and early miscarriage, that can lead to false positives. Some antibodies and certain medications can also affect test results. If there is a false-positive test result, it indicates that the test shows a woman is pregnant when she is not. It is also possible to obtain a false positive if the body produces antibodies that have fragments of the HCG molecule or if there are errors in the laboratory. If there are any doubts about the results, a different testing method can be used for verification.

If an HCG test comes back negative, it usually means that pregnancy has not occurred. However, if the test is conducted very early in the pregnancy—before the body has had enough time to produce sufficient HCG—a false negative result may occur. In the case of a false negative test, the test may indicate that a woman is not pregnant, while she is indeed pregnant. Since HCG levels change rapidly in the early stages of pregnancy, an HCG blood test can be repeated within 48 to 72 hours to monitor how hormone levels change

Beta HCG Values According to Pregnancy Weeks

Low HCG levels can be detected in the blood approximately 8 to 11 days after conception. HCG levels peak towards the end of the first trimester and then gradually decline throughout the remainder of the pregnancy. The HCG levels according to gestational weeks are as follows:

• 3 weeks: 6-70 IU/L
• 4 weeks: 10 - 750 IU/L
• 5 weeks: 200 - 7,100 IU/L
• 6 weeks: 160 - 32,000 IU/L
• 7 weeks: 3,700 - 160,000 IU/L
• 8 weeks: 32,000 - 150,000 IU/L
• 9 weeks: 64,000 - 150,000 IU/L
• 10 weeks: 47,000 - 190,000 IU/L
• 12 weeks: 28,000 - 210,000 IU/L
• 14 weeks: 14,000 - 63,000 IU/L
• 15 weeks: 12,000 - 71,000 IU/L
• 16 weeks: 9,000 - 56,000 IU/L
• 16 - 29 weeks (second trimester): 1,400 - 53,000 IU/L
• 29 - 41 weeks (third trimester): 940 - 60,000 IU/L

Beta HCG Values in Ectopic Pregnancy

An ectopic pregnancy is an abnormal pregnancy where the embryo attaches outside the uterus, typically in the fallopian tube, which carries the egg from the ovary to the uterus. Symptoms may include abdominal pain and vaginal bleeding. Ectopic pregnancy can be very serious and even life-threatening. During an ectopic pregnancy, HCG levels remain low. If a person's HCG level is slowly rising or decreasing, this may indicate that the pregnancy is ectopic. Normally, HCG levels that double every 48 hours show a 66% or less increase in ectopic pregnancies.

Beta HCG Test in IVF

In in vitro fertilization (IVF) treatment, it is generally considered sufficient to wait about 10-14 days after egg retrieval before conducting an HCG test. The blood test for HCG provides the most accurate results during this period. If HCG levels rise too rapidly during this process, it may suggest the occurrence of a multiple pregnancy.

Various blood tests performed on the mother during the pregnancy process can be decisive for the health of both the baby and the mother. It is essential to remember that HCG tests should not only be considered for pregnancy detection, but they may also need to be performed periodically for the detection of other conditions. If you have pregnancy symptoms and want to be sure, you can consult the nearest healthcare facility to have the necessary tests done.