A friend asked me: My periods are normal and my basal body temperature is biphasic, why I am always not pregnant. Luteinization of the follicle after a certain period of growth, but no real ovulation occurs, causing a series of phenomena called luteinization of the unruptured follicle (LUF). If LUF occurs repeatedly during the menstrual cycle, which affects the ability to conceive and leads to infertility, it is called luteinized unruptured follicle syndrome (LUFS), which is ovarian infertility. The diagnosis: ①Basal body temperature (BBT) is typically biphasic. (2) Regular menstruation with elevated progesterone level in the luteal phase. ③Cervical mucus or endometrial biopsy with normal tissue secretion signs. ④B ultrasound continuously traces follicles with mature follicles but no ovulation (vaginal ultrasound examination is performed from the 5th day of menstruation and every 1 to 2 days thereafter to observe follicular development, no sign of ovulation is seen after t3 of predicted ovulation and follicles continue to grow or exist after intramuscular injection of HCG 10000 U. The specific criteria were: the follicles with normal development were persistently enlarged without rupture; the envelope was gradually thickened, the boundaries were blurred and the tension was reduced; the follicles gradually changed from anechoic dark areas to a few faint light spots; the follicles gradually shrank and disappeared until after the next menstrual period). The follicular luteinization type (the follicle volume remains unchanged on the expected day of ovulation, the follicle wall gradually thickens, the follicle is filled with a large number of strong light spots for 2-4 days and then gradually disappears, the follicle diameter is around 25 mm or the follicle volume increases excessively on the expected day of ovulation, up to 31-50 mm in diameter, and there is no free fluid in the rectal fossa) and the persistent enlargement type.) The diagnosis of infertility due to LUFS was confirmed by the persistence of the above for 3 months. ⑤ Other causes of infertility were excluded.