Why is the beta reduced but the fetus still develops and has a fetal heart?

Question
Hello doctor,
March 5 is the first day of the last menstrual period (30 days), April 11 is late for my period, beta test is 3356. On April 15, beta 16,561, ultrasound has entered the uterus. . The doctor prescribed Utrogestan 2 tablets / day + nospa 2 tablets / day. On April 21, beta 10,800, 5w6d fetal ultrasound, with fetal heart rate. The doctor said to maintain the old prescription + add duphaston 2 tablets / day So can I keep the pregnancy? Why is the beta reduced but the fetus still develops and has a fetal heart? Thank you doctor.
Anonymous customer
Answer
Answered by Master, Doctor Trinh Thi Thanh Huyen - Obstetrician and Gynecologist - Department of Obstetrics and Gynecology - Vinmec Hai Phong International General Hospital
Hello,
With question Ask "Why is the beta reduced but the fetus still develops and has a fetal heart?" , the doctor would like to answer as follows:
HCG (Human Chorionic Gonadotropin) 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 produced shortly after the egg is fertilized and begins to implant in 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 are expecting to become pregnant are also provided by an obstetrician to monitor the pregnancy. The quantification of beta HCG allows early pregnancy diagnosis even if there are no signs of a missed period. Beta HCG levels increase 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.
Beta HCG test only helps to identify pregnancy, monitors fetal development through the development of the placenta, but does not completely reflect the gender, 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 baby's health can also be assessed through other indicators, other means. The beta index has a fairly wide reference range depending on the individual. For example, 5 weeks pregnant about beta 18 - 7,340mIU/ml; 6 weeks pregnant is 1080 - 56 mIU/ml. So with your gestational age of 5 weeks and 6 days, the beta value is still within the allowable range. However, compared to the previous index, there is a decrease. This decrease has many causes, first of all, the doctor needs to follow up with an ultrasound to evaluate the baby's development because this stage is still very early. If on ultrasound the fetus is still growing, you should follow up with your doctor's prescription, because it may be related to the development of the placenta. According to the advice, you should continue to monitor for another 1 week and do not worry too much because stress will affect the fetus and take the medicine prescribed by the doctor.
If you still have questions about beta levels, you can go to a hospital under Vinmec Health System for further testing and advice. Thank you for trusting and sending questions to Vinmec. Wishing you lots of health.
Best regards!