When Ms. Zhang’s period was delayed for a few days, she took a pregnancy test and unexpectedly found “two bars” – she was pregnant. However, within two days, her “great aunt” visited her. Ms. Zhang was surprised: did she have a false pregnancy? In fact, Ms. Zhang’s condition is called biochemical pregnancy. After the embryo is born, the trophoblast cells will secrete a large amount of beta-HCG, which will enter the mother’s blood and even urine, and can be detected by biochemical methods. However, at this time, the presence of the gestational sac cannot yet be detected by ultrasonography. For some reason, the embryo does not continue to develop and withers away, and then ends in the form of menstrual bleeding, a phenomenon called biochemical pregnancy, also known medically as “subclinical abortion”. A biochemical pregnancy is different from a miscarriage, as we often call it. Usually, the gestational sac can be seen by ultrasound 5-6 weeks after the embryo has been implanted, at which point it enters the clinical stage of pregnancy. The term miscarriage is often used to refer to the loss of pregnancy at this stage. Biochemical pregnancies often occur within 12 days of embryo implantation and are not yet at the clinical stage of pregnancy. An occasional biochemical pregnancy is not a problem Clinically, biochemical pregnancies are not uncommon, accounting for 25-30% of total pregnancies. However, many women tend to think that their “period” is capriciously late again, resulting in many biochemical pregnancies going undetected. Women who have regular periods can take a urine pregnancy test when they are not on schedule or have a late period, but it is best to go to the hospital for a blood test to determine if they are pregnant. If it is determined that the HCG is elevated, the doctor will need to determine the pregnancy based on the test results to avoid a biochemical pregnancy being mistaken for a late “period”. Biochemical pregnancies are essentially a form of natural selection, and a single biochemical pregnancy or miscarriage is a matter of chance, so there is no need to be too nervous, nor is there any need for treatment or therapy to continue trying to conceive. It is important to identify the cause of frequent embryo blight It is important to remind that if this happens several times, it is necessary to go to the hospital for further examination to find out the cause of the problem and to treat it in a targeted manner. The causes of biochemical pregnancy are still unclear, and there are many factors affecting it, the common ones are as follows: 1. The embryo settles in the wrong home. In the early stage of embryo implantation, the naughty embryo will mistake the fallopian tube, cervix and ovaries for the uterus and take root there, i.e. ectopic pregnancy, which is commonly known as ectopic pregnancy. The embryo is destined to wither away because the place where it is bedded is not suitable for the embryo to grow. 2. The embryo itself is of poor quality. The quality of the eggs and sperm or the mutations that occur in the process of forming the embryo may affect the quality of the embryo and cause it to wither and stop. 3. There are problems with chromosomes of both spouses. In this case, the probability of normal embryos is low. 4. Luteal insufficiency. Insufficient estrogen and progesterone secreted by the corpus luteum can easily lead to embryonic abortion. 5. Problems with coagulation function. Some women suffer from easy embolism, some small arteries of the uterus may have small blood clots and other coagulation problems, so that the embryo can not develop normally. 6, the existence of some diseases in women themselves. Such as diabetes, immune system diseases, pelvic inflammatory disease, reproductive system infection, etc., may lead to embryonic abortion.