To increase the chances of pregnancy, the optimal ovarian follicle size (as measured by doctors) is usually between 18 mm and 24 mm at the time of ovulation.
Natural conception: Follicles between 18 and 24 mm are considered mature and ready for fertilization.
IUI/IVF treatments: Follicles between 16 and 22 mm may also be viable, depending on individual health and treatment protocols.
Before ovulation, the average diameter of the dominant egg should be 22 to 24 mm (range: 18–36 mm). It is the only marker that can easily predict ovulation.
The minimum follicle size for a mature egg that can result in pregnancy is approximately 18 mm to 20 mm in diameter.
The optimal ovarian follicle size for conception is between 18 mm and 22 mm. Follicles within this range are considered mature and ready for ovulation.