What is Beta HCG and how is it related to gestational age?

The article was professionally consulted by Doctor Nguyen Thi Hong On - Department of Obstetrics and Gynecology, Vinmec Phu Quoc International General Hospital.

HCG is a test that indirectly reflects the health status of the fetus. However, what is the nature of beta HCG concentration, the meaning of HCG quantification is not well understood. So let's find out information through the article below.

In the womb, the fetus is nourished by the placenta through the umbilical cord. The placenta is responsible for the metabolic barrier between the mother's body and the fetus. In addition, the placenta also has an endocrine function by secreting hormones that regulate pregnancy.
One of those hormones is HCG (Human Chorionic Gonadotropin). This is a peptide hormone, secreted from the trophoblast, and plays a role in activating the embryonic germ cells to develop and mature. At the same time, HCG also helps stimulate the secretion of sex hormones, forming the sex of the fetus.

HCG is born right after the egg is fertilized and begins to implant on the lining of the uterus. At this time, the concentration of HCG will appear in the blood, increasing rapidly until reaching the maximum concentration at two and a half months. After this period, the amount of HCG will gradually decrease to a stable level around the fourth month and continue until delivery.
Structurally, HCG consists of two different subunits, called alpha and beta. Since the alpha subunit resembles the alpha chain of FSH and LH, only the beta subunit is specific for HCG, quantification of HCG beta levels becomes the basis for HCG quantification, which is of interest to more than just women. women who expect to be pregnant, but also by an obstetrician who monitors the pregnancy.

Immediately after being formed by the placenta, HCG will quickly diffuse upstream into the mother's blood and be excreted unchanged in the urine. Thus, it is possible to identify or quantify HCG in the blood and urine of pregnant women. This is the basis of using a pregnancy test that contains a beta HCG reagent. So this test is the earliest sign of pregnancy.

This test is the earliest sign of pregnancy. At the same time, at the hospital, measuring the concentration of HCG in the blood by radioactive or biochemical methods to determine the gestational age as well as indirectly assess the health status of the pregnancy.

The measurement of beta HCG allows early pregnancy diagnosis even when there are no signs of a missed period. By accurately measuring beta HCG levels with high sensitivity, it is possible to determine conception as early as the 8th, 9th day after ovulation, which is the 22nd and 23rd day of the menstrual cycle (applicable to women who are pregnant). Women have regular menstrual cycles of about 28 days.
After that, beta HCG levels increase very rapidly, doubling in just 1.4 to 2 days when the zygote begins to implant. HCG will reach its highest level at 60 to 70 days and gradually decrease to its lowest level, stabilizing around 100 to 130 days.

Besides being able to determine the gestational age, the beta HCG blood test also helps to monitor the status of the pregnancy. When blood beta HCG measurements do not conform to the normal physiological curve, an abnormal pregnancy is suspected.
If the first occurrence of HCG in the blood or urine was first evidenced, and now the repeat test is low, and the HCG level does not increase commensurate with gestational age, it is possible that the pregnancy was aborted, stillborn, or pregnant. ectopic pregnancy.
On the contrary, if the HCG level is abnormally high, consider the possibility of calculating the gestational age of preterm pregnancy, pregnancy with multiples or ovum, trophoblastic disease...

Beta HCG blood test also helps monitor pregnancy status
Beta HCG test only helps confirm pregnancy, monitors fetal development through the development of the placenta, not at all What does it mean about the sex, weight, and intelligence of the fetus? Therefore, pregnant mothers should not be too worried about beta HCG levels, should not monitor the test continuously, while the health of the baby can also be assessed through other indicators, other means. . Accordingly, it is necessary for pregnant women to have a healthy pregnancy, combine proper eating, exercise and rest, and be ready to welcome the birth of their baby.