It can be difficult and complicated to determine the cause of ovulation problems. Possible causes may include:

• Hormonal imbalances. 70% of all women with ovulation problems have hormonal imbalances related to polycystic ovary syndrome (PCOS).¹ Other ovulation problems can originate in the ovaries, or in the pituitary gland and hypothalamus, which produce hormones that regulate the menstrual cycle. These hormones are vital to normal ovulation.
• Structural problems. Abnormalities in the structure of the ovaries (such as ovarian cysts) or structural problems in other reproductive organs can cause changes in a woman's ovulation schedule.
• General medical problems. Medical problems that affect the metabolism (such as thyroid problems), serious illness, emotional stress, overweight and low weight, or excessive exercise can affect a woman's ovulation schedule.
• Cancer treatment. Exposure to certain kinds of chemotherapy or radiation can damage the egg supply in the ovaries.