The value of estradiol on the 3rd day of menstruation depends on the unit of reference value, there are two normal units: one is pg/ml and the other is pmol/L. If pg/ml is normal on the 3rd day estradiol value is 20-50 pg/ml and pmol/L should be 46-610 pmol/L, the unit factor for conversion of these two indicators is 3.67pmol/L . If it exceeds 60 pg/ml, it means that estradiol is elevated and there may be early follicular development, if it exceeds 80 pg/ml, it means that the follicles rarely ovulate, if it exceeds 100 pg/ml, there is no ovulation. This indicates that there is diminished ovarian function. If the value is below 20pg/ml, it tends to affect menstruation and follicle development. If the value of pmol/L increases or decreases, it will have an impact on the body. The 3rd day of normal menstruation is the follicular phase, the period with the lowest estrogen level.