Hello Sarah Thanks for writing to us with your health concern. Please do write in with few more details. For example, your normal menstrual cycle. In a regular 28 day menstrual cycle, ovulation normally occurs around day 14. On day 14, the follicle size is generally 18 - 22 mm, when it is ready to rupture ( ovulate ). In your case, the egg size on day 13 is not optimum. If you have delayed cycles, then maybe the egg will grow to the correct size in a few days, and then rupture. You need to continue having folliculometry for a few more days. Please remain sexually active as soon as ovulation is documented on the scan. If a few cycles of follicular monitoring fail, then you need to have a laproscopy to check if the fallopian tubes are open or blocked. If ovulation is not documented, then ovulation inducing agents like clomiphene citrate maybe required to stimulate the ovaries. All the best. Take care.