Anovulation is the medical term for the absence of ovulation. The ovary releases a mature egg cell into the fallopian tube during the menstrual cycle and this process is known as ovulation. It can occur approximately 14 to 16 days before the start of menstruation (refer to Ovulation Schedule). In anovulation, this process does not occur.
The ovary may not release a mature egg cell for a number of reasons including ovarian disorders, menopause or perimenopause, pregnancy, hormone contraceptives, drugs or even severe stress, exercise and starvation (including strict dieting). Other chronic conditions, even those that are not gynecological in origin, may result in anovulation.

Ovulation is controlled by two female hormones, known as follicle-stimulating hormone (FSH) and luteinizing hormone (LH) which may be monitored in cases of infertility or difficulty in conceiving. A regular menstrual cycle lasts between 28 to 32 days although a cycle as short as 26 days or as long as 35 days is considered within the norm. Ovulation usually occurs approximately 14 to 16 days before the next period but this may vary depending on the length of the individual menstrual cycle. The most fertile period is considered to last approximately 3 to 4 days within the cycle starting a day or two before ovulation. If the egg cell is not fertilized within this time period, it is ‘discarded’.