Ovulation and the normal menstrual cycle involves an amazing interaction between the hypothalamus section of the brain, the pituitary gland and the ovaries.
This interaction can be affected by many factors. The three most common are excessive weight gain or loss, excessive exercise and extreme emotional stress.
The hormones which are produced also can be affected by factors relating to a woman's physiology.
About 25% of evaluated infertility is due to an ovulation abnormality. Ovulation abnormality can be treated by medications which affect hormonal secretion and regulate the cycle to allow ovulation to occur.