If you don’t detect ovulation on the sixteenth day of menstruation, you can use the following ways to deal with it: continue to observe, ultrasound to monitor the follicles, and use drugs to promote follicle development and ovulation. 1. Continue to observe: female ovulation can be affected by many factors, such as: emotion, sleep, environment, medication, etc., it is not uncommon for ovulation to occur earlier or later, if there is no ovulation on the sixteenth day of menstruation, you can continue to observe whether there is a delay in ovulation. 2. Ultrasound monitoring of follicles: If ovulation is not detected during the current menstrual cycle, ultrasound monitoring can be performed every other day, one week before the next ovulation, to observe follicular development and ovulation to see if there is any abnormality. 3. Use of drugs to promote follicular development and ovulation: If there are abnormalities in follicular development and ovulation, hormonal drugs can be used to adjust the menstrual cycle under the guidance of the doctor (ethinyl estradiol cyproterone tablets, drospirenone ethinyl estradiol tablets, etc.), and then drugs to promote the development of follicles (letrozole, clomiphene, etc.), and then after the follicles are matured, ovulation can be stimulated with human chorionic gonadotrophin. The above treatments should be carried out under the guidance of clinicians to avoid adverse reactions.