There are many causes of recurrent spontaneous abortion, endocrine factors 10%. The formation of corpus luteum after ovulation secretes progesterone, which changes the endometrium into a secretory phase in preparation for the implantation of the pregnant egg. If luteinizing hormone is not secreted enough, the endometrium is not prepared for the secretory phase, which affects the early development of the embryo and will lead to miscarriage. The most common endocrine cause of habitual miscarriage is luteinizing insufficiency. Luteinizing insufficiency is mostly seen in pregnant women with polycystic ovary syndrome, endometriosis, and poor ovulation induction with low A. In patients with insulin-dependent diabetes mellitus, uterine blood flow can be affected by vasculopathy, which can affect embryonic development. Insufficient luteal function can be enhanced by induction of ovulation, luteal phase with HCG or oral progesterone. Low thyroid function is also prone to miscarriage and can be treated with thyroid supplementation, which is seen more rarely.