The problem of low menstrual flow: now many patients have reduced menstruation, if it is reduced by half than before, the cause should be investigated, you can check the ultrasound around the 15th day of menstruation to see the thickness of the endometrium, if it is above 8mm, it usually does not affect conception, if it is very thin, you can check the endocrine level in 3 to 5 days of menstruation to see if there is a problem with ovarian function, and there is also the adhesion of the uterine cavity after abortion, you can do hysterosalpingography to find the problem.