Women who are not consistently ovulating typically have irregular menstrual cycles. Periods are usually unpredictable and occur at infrequent intervals, although occasionally they may occur at shorter than normal intervals. For some women their periods have always been like this, whereas in others, the menstrual irregularity is recent in onset. Thyroid disease is more prevalent in women than men so women with irregular menses should have their thyroid hormones measured. Excess prolactin production can also cause ovulatory dysfunction.
Prolactin is a hormone that stimulates milk production by the breast.
Therefore women with irregular menses should have their prolactin measured regardless of whether or not they have galactorrhea. Stress, whether that be emotional or physical, can affect ovulation. We now know that the higher brain centers that ultimately control ovarian function can be inhibited by various hormones and neurotransmitters that are released in response to stress. The stress could be due to a recent systemic illness or could be psychologic in origin, i.e. recent death in the family, job change, divorce, etc. The ovulatory dysfunction generally resolves when the stress resolves.