Luteal function refers to the endocrine function of the corpus luteum formed by the ovary after ovulation through the secretion of hormones. Under normal circumstances, the corpus luteum is formed after ovulation, and the luteal cells secrete progesterone and estrogen under the action of LH. Luteal function peaks 7-8 days after ovulation, with a high level of luteinizing hormone secretion and a renewed rise in estradiol secretion. If conception does not occur, it begins to decline on the 9th day. The life span of the corpus luteum is relatively constant, usually 14 days. If luteal insufficiency occurs in an infertile state, it may shorten the menstrual cycle. If luteal insufficiency occurs early in pregnancy and progesterone secretion is insufficient, it may lead to conditions such as preterm miscarriage. If luteal insufficiency is detected, it is recommended to follow the doctor’s instructions to carry out the appropriate supplemental treatment and to review the luteal function regularly.