Nowadays, it seems to be a common thing to go to the hospital to have a blood test for progesterone as soon as you find out you are pregnant. If the progesterone is found to be low, many mothers-to-be feel as if they are in danger, anxious and panic-stricken, repeatedly going to the hospital for monitoring, and even taking a lot of progesterone orally to “calm the fetus”, as if low progesterone will definitely lead to miscarriage. There are also many doctors who have misconceptions about progesterone and prescribe progesterone just because of “low progesterone” when the mother-to-be has no signs of vaginal bleeding and other signs of preterm miscarriage, or prescribe progesterone arbitrarily to avoid responsibility because of the sharp contradiction between doctors and patients in China, which has resulted in a large number of clinical This has led to a large number of unregulated medications in clinical practice. The monitoring of progesterone level in early pregnancy has formed a confusing situation in today’s clinic, which has become a source of panic among pregnant women, excessive diagnosis and treatment, and abuse of birth control drugs. So should progesterone be routinely monitored in early pregnancy or not? In early pregnancy, progesterone is secreted by the corpus luteum of pregnancy, which can promote endometrial metaphase for good embryo implantation and induce immune protection mechanism to avoid embryo rejection by the mother. In addition, progesterone reduces the sensitivity of the smooth muscle of the uterus and prevents the uterus from contracting, which has a “calming” effect on the fetus. Progesterone is undoubtedly important for the maintenance of a stable fertility status, but we do not recommend it as a routine monitoring indicator during pregnancy. However, we do not recommend progesterone as a routine monitoring indicator during pregnancy, because serum progesterone levels vary greatly from person to person, even if the same person has different progesterone levels at different times, which is related to the peak of progesterone pulse and the function of progesterone receptors. In fact, a low progesterone level is not a judge of pregnancy outcome. On the contrary, we often encounter many pregnant women with persistently low progesterone levels, but without signs of miscarriage such as vaginal bleeding, who eventually continue their pregnancy well until delivery. Second, there are various reasons for miscarriage People monitor progesterone levels in early pregnancy mainly because of the fear of miscarriage. Fear of pregnancy loss due to low progesterone, can progesterone supplementation really prevent and treat miscarriage? The etiology of spontaneous miscarriage is very complex, with half or more of spontaneous miscarriages being random chromosomal abnormalities, or aneuploidy, that occur during embryo division. Other factors include systemic factors (infection, malnutrition, etc.), uterine abnormalities, endocrine abnormalities, immune function abnormalities, and bad habits (alcohol and drug abuse). Of these, only endocrine abnormalities such as luteal insufficiency, hyperprolactinemia, and polycystic ovary syndrome may be associated with miscarriage due to low progesterone. So if you have a history of any of these, you can monitor your progesterone levels and supplement with the right amount of progesterone. In addition, if you conceived this baby through IVF, the use of ovulation reduction and gonadotropins in assisted reproductive technology, together with the loss of granulosa cells during egg retrieval, the ovarian corpus luteum function is significantly incomplete, and progesterone supplementation is beneficial to the development of the embryo. The progesterone is produced by the corpus luteum after ovulation, but after 8-10 weeks of pregnancy, the progesterone secreted by the corpus luteum gradually decreases and is gradually secreted by the syncytial trophoblast of the placental villi until delivery. This alternation indicates that the era of ovarian corpus luteum support has passed and the era of placental trophoblast cells comes next. If the embryo itself does not develop well and the trophoblast cells cannot secrete progesterone properly, then no amount of progesterone supplementation will help. The low progesterone level at this stage is not the cause of miscarriage, but the result of the embryo’s own poor development. That is why it is also common in clinical practice to encounter patients with unavoidable miscarriage or indolent miscarriage after 8 weeks, where preservation of the fetus does not change the outcome of their pregnancy. Therefore, for these reasons, we do not recommend progesterone as a routine indicator for pregnancy monitoring. If you do not have a history of endocrine disorders such as hyperprolactinemia or polycystic ovary syndrome, and if you do not have abnormal symptoms such as vaginal bleeding, you just need to wait for the natural development of the embryo and go to the hospital for ultrasound examination after 6 weeks of menopause. The appearance of embryonic buds and primitive heart tube pulsations are the first signs of a well-developed embryo.