What Is HCG Hormone? Its Functions and Important Roles in Pregnancy

HCG, or Human Chorionic Gonadotropin, is a hormone that plays a critical role during pregnancy. If you have ever heard about a pregnancy test, this hormone is what is tested to determine whether someone is pregnant. It is unique and specific because it is only produced by the woman’s body after fertilization. Below is an explanation of the HCG hormone, its functions in the body, and why this hormone is so important during pregnancy.

What Is the HCG Hormone?

HCG, or Human Chorionic Gonadotropin, is a hormone produced by the trophoblast cells after fertilization occurs. It starts to be produced immediately after the fertilized egg implants in the uterus lining and plays an important role in maintaining the corpus luteum, which produces progesterone. Progesterone is essential to maintain the uterine lining that supports embryo growth. Therefore, HCG ensures the continuation of early pregnancy.

Besides its vital role in pregnancy, HCG is also the basis for pregnancy tests. The detection of this hormone in the blood or urine is typically done about 10-14 days after fertilization, making it a reliable early indicator of pregnancy. This test can provide accurate results before physical pregnancy signs appear, making HCG an essential marker in the medical field to detect and confirm pregnancy.

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Functions of the HCG Hormone in the Body

1. Maintains the Corpus Luteum

HCG plays a role in maintaining the corpus luteum in the ovaries. The corpus luteum is responsible for producing progesterone, a hormone crucial for sustaining pregnancy. Progesterone helps maintain the uterine lining by keeping it thick and rich in blood vessels, creating an optimal environment for embryo development.

2. Prevents Decline in Progesterone

Without HCG, the corpus luteum would deteriorate, leading to a decline in progesterone production. This decrease could cause the uterine lining to break down, potentially leading to a miscarriage in early pregnancy.

3. Stimulates the Production of Other Hormones

In addition to maintaining the corpus luteum, HCG stimulates the body to produce other hormones required during pregnancy, such as estrogen. This function is crucial during the early weeks of pregnancy before the placenta is fully formed and capable of taking over the production of these essential hormones.

4. Maintains Pregnancy Stability

By ensuring the production of essential hormones, HCG plays a role in maintaining the stability and continuation of pregnancy until the placenta can function independently.

Read more: Understanding Gonadotropin-Releasing Hormone (GnRH): Its Role and Function

HCG Hormone’s Role in Pregnancy Tests

The HCG hormone plays a central role in pregnancy tests, which are the primary method for confirming pregnancy. Once the fertilized egg implants on the uterine wall, the body starts producing HCG in increasing amounts. This rise in HCG levels is the basis of most pregnancy tests.

Home pregnancy tests, which are typically conducted using a urine sample, are designed to detect the presence of HCG. These tests are highly sensitive to changes in HCG levels, allowing for the detection of pregnancy as early as 10-14 days after fertilization. This timing coincides with when the fertilized egg has been attached to the uterine wall long enough for HCG levels to rise significantly. Therefore, a woman can get accurate results from a urine test even before she experiences a missed period.

In addition to urine tests, blood tests conducted in a laboratory can also detect HCG, but with higher sensitivity. These blood tests not only confirm pregnancy earlier but also provide information about the specific HCG levels. This is useful for monitoring the pregnancy’s development and identifying potential issues such as ectopic pregnancies or the risk of miscarriage. HCG levels typically peak around 8-11 weeks of pregnancy and then begin to decline and stabilize as the placenta takes over the role of supporting the pregnancy. Thus, HCG is not just an early marker of pregnancy but also an important indicator used to monitor the health and progress of the pregnancy during the first trimester.

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What Happens If HCG Levels Are Abnormal?

Abnormal HCG levels can indicate problems with pregnancy, and it’s important to understand what might happen if HCG levels fall outside the expected range.

Low HCG Levels

If HCG levels are low or fail to increase as expected during early pregnancy, this could be a sign of a serious issue, such as a threatened miscarriage. In a normal pregnancy, HCG levels should rise significantly every two to three days during the first few weeks. When this increase does not occur, doctors may suspect that the pregnancy is not progressing as it should.

In addition to the risk of miscarriage, low HCG levels could also indicate an ectopic pregnancy, a condition where the embryo implants and grows outside the uterus, typically in the fallopian tube. Ectopic pregnancies are medical emergencies that require immediate treatment as they can be life-threatening for the mother.

High HCG Levels

On the other hand, very high HCG levels could indicate a multiple pregnancy, where the body produces more HCG to support more than one fetus. While this can be good news for some couples, very high HCG levels could also point to a more serious condition.

One such condition is molar pregnancy, a rare disorder where abnormal tissue grows inside the uterus. In a molar pregnancy, the tissue resembles small grape clusters and can cause HCG levels to rise much higher than typically seen in a normal pregnancy. This condition requires immediate medical attention to avoid further complications.

Monitoring HCG levels during early pregnancy is an essential step in ensuring the health of both the mother and the fetus. If HCG levels are abnormal, whether too low or too high, prompt medical evaluation and intervention are necessary to determine the cause and ensure the pregnancy remains safe.

Read more: Luteinizing Hormone (LH): Understanding Its Role in Reproductive Health

HCG is a vital hormone that supports the early stages of pregnancy by maintaining the production of progesterone necessary to sustain pregnancy until the placenta develops properly. Understanding what HCG is and its function in the body can help explain many aspects related to pregnancy, from pregnancy tests to diagnosing pregnancy complications. As a hormone produced only during pregnancy, HCG plays an irreplaceable role, both in ensuring the continuation of a healthy pregnancy and in early diagnosis if any issues arise.

For more in-depth information on reproductive health, pregnancy programs, or solutions for infertility problems, the doctors at Morula IVF Indonesia are ready to help. Morula IVF Fertility Clinic offers comprehensive and professional consultations, as well as advanced technologies such as Artificial Insemination, In Vitro Fertilization (IVF), and more. With over two decades of experience, Morula IVF has a team of dedicated obstetric specialists to support you in your journey to have a healthy child. Contact Morula IVF through their official website or directly for more information and consultations.

References:

• American Pregnancy Association. (n.d.). HCG Levels. Accessed September 2024.
• Pregnancy, Birth & Baby. (n.d.). HCG Levels. Accessed September 2024.
• Medscape. (n.d.). Human Chorionic Gonadotropin (HCG). Accessed September 2024.
• ScienceDirect. (n.d.). Human Chorionic Gonadotropin. Accessed September 2024.
• Healthline. (n.d.). Low HCG Levels During Pregnancy: What It Means. Accessed September 2024.
• Parents. (n.d.). Understanding HCG Levels. Accessed September 2024.