To give you a proper understanding of miscarriage preservation, let me first tell you some basic facts about pregnancy and miscarriage: the total clinical pregnancy miscarriage rate is about 15% in the whole female population, and the total embryo loss rate is as high as 60-70% if we count biochemical pregnancies, and only about one-third of all conceived embryos are transformed into viable newborns. What is a biochemical pregnancy? A miscarriage occurs at a very early stage of pregnancy, without the woman being aware of it, and may not show any signs at all, but at most a slight delay in menstruation for a few days and a slightly heavier period. Pregnancy is actually a process of trial and error, and a process of natural selection and natural elimination. The most important cause of spontaneous miscarriage is chromosomal abnormality of the embryo, the proportion is about 50%, other main causes are maternal factors, including anatomical abnormalities of reproductive organs, autoimmune factors, infectious factors, endocrine factors, unexplained factors (including thrombotic tendency, etc.), the proportion of miscarriage caused by lack of progesterone level due to luteal insufficiency is very small. Routine measurement of progesterone levels is not recommended to guide early pregnancy preservation Clinical reasons for testing progesterone levels (a cause of miscarriage): luteal insufficiency (a very small percentage), which can lead to low progesterone levels and further lead to miscarriage. If detected in time, progesterone can be supplemented to prevent miscarriage from occurring. In fact, the gold standard for the diagnosis of luteal insufficiency is to perform an endometrial biopsy at mid-luteal phase, but since two consecutive endometrial biopsies are required to diagnose luteal insufficiency, it is almost impossible to use the gold standard for diagnosis in clinical practice. Therefore, it has been proposed to check progesterone levels to determine luteal function, but this method is not reliable: 1. Progesterone levels in normal pregnancy fluctuate widely. 2, Low progesterone levels are more likely to be a result of poor embryonic development rather than a cause to be miscarried. 3, Half of the patients diagnosed with luteal insufficiency have normal progesterone levels. 4. During early pregnancy, there are two sources of progesterone, one is secreted by the corpus luteum and the other by the trophoblast, so it is impossible to determine which cause of low levels is responsible. Therefore, it is not recommended to routinely measure progesterone levels to guide fetal preservation. Of course, the usefulness of progesterone testing should not be dismissed in general. After a positive hCG test, when ultrasound does not reveal evidence of pregnancy, progesterone level testing is still helpful in determining the prognosis of pregnancy, and low levels of progesterone mean that miscarriage and ectopic pregnancy are more likely. However, the purpose of progesterone testing is definitely not to supplement progesterone. Bed rest is not recommended for pregnancy preservation Even if you repeat that there is no evidence-based medical evidence that bed rest can reduce the incidence of miscarriage, there will still be many mothers-to-be, especially their mothers-in-law, who will not listen. In one of the most bizarre cases, my daughter had a spontaneous miscarriage in her first pregnancy, and after her second pregnancy, her mother forced her daughter to be on absolute bed rest, eating, drinking, pooping, and not being allowed to get off the floor for 6 months. By the time she brought her daughter to my clinic, she was already walking wobbly and the muscles of her lower limbs were found to be significantly atrophied during the examination, which was ridiculous! In fact, without evidence-based medical evidence, common sense should be able to tell that bed rest to preserve the pregnancy is useless. Nearly half of all miscarriages are due to chromosomal abnormalities of the embryo, and this situation is doomed to miscarriage no matter what you do, not to mention bed rest, even if the patient is given progesterone every day, or even soaked in progesterone. Routine application of oral or intramuscular progesterone for miscarriage preservation is not recommended The latest Cochrane review on progesterone for miscarriage prevention published in 2013 (the most authoritative evidence-based medicine) concluded that the application of progesterone (either intramuscular or oral) for miscarriage prevention is ineffective. For three or more consecutive spontaneous abortions, empirical progesterone supplementation may be beneficial, but this needs to be further confirmed by a large sample of multicenter studies. If the application of progesterone is ineffective in preventing miscarriage, why is it necessary to test progesterone levels to guide the prevention of miscarriage? The WHO (World Health Organization) also does not recommend progesterone for fetal preservation. Of course, progesterone supplementation may be needed in a few cases, such as patients who have had their corpus luteum surgically removed during early pregnancy and some IVF patients whose progesterone levels have dropped due to surgical procedures.