14 days after embryo transfer, 12 days after blastocyst transfer, is pregnant mothers have to go to the hospital to draw blood HCG and P time, according to the results of HCG can determine whether pregnancy. So what is HCG? What do you know about HCG?
HCG, or human chorionic gonadotropin, is a glycoprotein secreted by placental trophoblast cells. After fertilization, HCG enters the mother's blood and increases rapidly until the 8th to 10th week of gestation.
How does HCG come about? When a fertilized egg implants, it reaches out its branch-like antennae and grabs the uterine wall. These antennae are villi, and it forms the early placenta. When the placenta is not mature, these hairs grow and attach to form a thin membrane. These chorionic membranes are gradually filled with blood vessels, which serve as the primary link between maternal and embryonic nutrients and waste products. The growth of this villi is what we call a doubling. In the first three months of gestation, HCG levels roughly double every 2.2±0.5 days. The absolute value of serum HCG varies greatly in different stages of pregnancy and among pregnant women. So you don't have to compare yourself to others, as long as your HCG increases normally. However, if the HCG is not doubled or the doubling is not good, the possibility of biochemical pregnancy or ectopic pregnancy should be considered. Ectopic pregnancy is usually accompanied by obvious symptoms, such as low progesterone, abdominal pain, bleeding and so on. Seek medical attention promptly.
High HCG on day 14. Is it a twin? The blood HCG level of twins is generally higher than that of singletons, but that does not mean that a high blood HCG level is necessarily a twin. At present, the diagnosis of multiple births, B ultrasound is still the gold standard. Blood value is only a qualitative criterion, and cannot be considered as twins. In addition, the blood HCG concentrations in patients with hydatidiform mole, choriocarcinoma and RH incompatibility were all higher than those in normal pregnant women. For example, in hydatidiform mole, the blood HCG concentration is often significantly higher than the corresponding value in normal gestational weeks, and continues to rise after 8 ~ 10 weeks of menopause. About 45% of patients with complete hydatidiform mole had serum HCG levels above 100 000U/L. The serum free HCG level of the fetus with down syndrome is increased, so HCG can also be used as a serum biochemical marker for prenatal screening.
Another very important role of HCG is to reduce the rejection reaction of pregnant mothers. If you have a parasite on your body, generally speaking, your immune system is going to attack, but the HCG confuses the mother and tells her it's safe, it's your own, so your immune system doesn't work. The synergistic effect of HCG and progesterone, on the one hand, enables the embryo to obtain nutrients, and on the other hand, ensures the safety of the embryo, so it is necessary to have both. HCG doubling is not good, because of the lack of nutrients, the embryo may be stunted or even stopped. Not enough progesterone, the embryo will implant instability, causing bleeding and even abortion. However, the low value of HCG and progesterone does not necessarily lead to miscarriage, but the probability of miscarriage is high. Once bleeding occurs, it should be tested. If there is adverse pregnancy history before, monitoring can also be taken as a precaution.