How Many Eggs Does an Ovary Produce?

Under normal physiological conditions, women are born with two ovaries, each containing a predetermined number of eggs. At birth, a newborn girl has approximately 1 to 2 million primordial oocytes in her ovaries. However, by the onset of puberty, through a natural process called follicular atresia, this number decreases significantly, leaving around 300,000 to 400,000 oocytes by the time of menarche (the first menstrual period).

Only about 300 to 500 of these eggs will reach full maturity in a healthy woman, typically one per menstrual cycle.

Controlled ovarian stimulation is an assisted reproduction technique used to promote multifollicular development, meaning multiple eggs per cycle. This technique is used in in vitro fertilization (IVF) treatments or in oocyte vitrification processes. The chances of treatment success rate increase with the number of mature oocytes obtained.