Ovulation does not occur every day.

Eggs usually only survive for about 48 hours during a woman's menstrual cycle, so about 4-5 eggs are usually released in a day during a woman's cycle. These eggs are called mature eggs because they have waited approximately 48 hours to be released.

However, not all mature eggs will be fertilized. Sometimes, only 1-2 eggs will be fertilized, while the others will die or be expelled. This process is called fertilization and implantation, and they occur in the female reproductive organs.

So while a woman typically has about 12 eggs during her menstrual cycle, not every egg will be fertilized. During a woman's cycle, only about 4-5 mature eggs are fertilized and implanted to form a fertilized egg.