Ovulation is the release of a ripe ovum (egg) from the ovary of a female and is fundamental to the process of pregnancy. Anovulation is the medical term used if ovulation does not occur in a woman. Such women can still have some menstruations, although often they do not (amenorrhoea). Anovulation is diagnosed in 20-25% of couples presenting with fertility disorders.

Anovulation is mostly characterised by cycle disorders such as amenorrhoea (absence of menstruations) or oligomenorrhea.

Tests
If a woman monitors her basal body temperature (BBT) and does not see a slight rise in her temperature approximately half way through her cycle, then this is an indication that she is not ovulating.

The absence of thin, watery cervical mucous midcyle can also indicate the absence of ovulation. There are also ovulation tests that women can perform at home.

Anovulation can be caused by a number of different factors, including hormonal disorders, age and premature menopause. Three different categories are often distinguished:

1. The cause is located centrally at the level of the brain (hypothalamus, pituitary).
2. There is a disturbed balance between the pituitary and the ovaries (such as PCO).
3. The cause lies at the ovarian level (such as premature menopause).
4. A heightened prolactin level can belong in either category 1 or 2.

Treatment for anovulation ranges from medication (both pills and injections) to more complicated procedures. The type of treatment that is most suitable will depend on, amongst other things, the underlying cause of the anovulation. In general, the simplest method of treatment is used to start with. Other treatment may then be embarked on until a successful ovulation occurs.

The simplest treatment is the use of ovulation stimulating medication. In the most extreme cases, in vitro fertilisation (IVF) treatment could be considered. Only if there are no further available ova - as in premature menopause for example - will donor ova be considered as a final option.