Most women of childbearing age who have menstrual disorders, suspected endocrine disorders, or infertility need to have their sex hormones tested during the follicular phase. The test is done on the second or third day of menstruation and the results are based on the follicular phase. The test must be done on an empty stomach, otherwise the results will be affected if you have eaten food. In addition, it is advisable to take a 10-minute rest before the blood draw, mainly because strenuous exercise can lead to a slight increase in prolactin, which will have a certain effect and make the results not very clinically relevant.