The ability of the embryo to develop healthily in the uterus requires that the embryo itself be healthy, adequately nourished, with a coordinated action of various hormones, and protected from harmful external factors. Currently science is not able to reach the point where all the elements of embryonic growth are known and the environment of the uterus is mimicked in vitro so that the embryo is fully developed to maturity outside the body, for example one can only culture the fertilized egg outside the body for 5-6 days, and if the culture is continued next, the embryo will gradually die. Therefore, IVF fertilized eggs are mostly transferred into the body at the 8-cell stage on day 3, or at the blastocyst stage on day 5-6. It would be a miracle if humans could culture embryos to maturity in vitro. Repeated miscarriage (or embryonic abortion) means that the embryo itself may not be healthy or that the environment of the uterus is not conducive to embryo growth. It is not yet possible to understand all the factors that cause embryos to stop developing; one can only rank the common ones one by one. First, chromosomal problems in the couple or in the fertilized egg, which accounts for about 10% of all embryonic arrests. Secondly, abnormal uterine morphology is often a factor in recurrent miscarriages, accounting for about 30%. Again, an abnormal endocrine environment is often the culprit of recurrent miscarriages, which includes abnormal luteal development, abnormal thyroid function, abnormal adrenal function (abnormal blood sugar), and abnormal pituitary ovarian hormones. Then secondly, there are infectious factors such as toxoplasmosis and rubella virus. Recently, uterine adhesions and endometrial inflammation have also been gaining attention. It has also been noticed that people with recurrent miscarriages often have the presence of autoantibodies, or antibodies of the same kind, i.e. the so-called immune mechanism is so deranged that the mother rejects the embryo containing foreign antigens. Finally, it is tantalizing for doctors and patients that despite all the tests done, about half of the patients cannot find any cause. This indicates that there are still considerable limitations in the understanding of embryonic abortion. Recurrent miscarriages due to chromosomal abnormalities are selected by nature, and the mechanism of this selection will eliminate the undesirable embryos so that the healthy and quality genes of human beings can be carried forward to inherit and reproduce. Recurrent miscarriages due to this factor are not treatable and we choose to go with the flow of nature and we do not advocate fertility preservation treatment. Recurrent miscarriages due to abnormal uterine morphology can be corrected surgically in some cases, but not in others. Recurrent miscarriage due to infection is mostly treatable. Recurrent miscarriages due to endocrine abnormalities can be regulated. For those due to immune factors, active immunotherapy with husband’s lymphocytes and passive treatment with intravenous gammaglobulin have been reported to be about 70% to 80% effective. Recurrent miscarriage is still a persistent and difficult disease, and sometimes we are at our wits’ end. However, active exploration and treatment can sometimes yield unexpected results. As scientists continue to explore, people will eventually overcome it gradually. The most promising method may be the implementation of in vitro culture.