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Anovulation

Women with anovulation who are not wishing to conceive should use appropriate contraception as they could ovulate during some menstrual cycles

What is anovulation?

A large number of immature eggs are formed in the ovaries of every woman before she is born and these gradually get used up with the passage of time. One (occasionally two) of these eggs mature and is (are) released (ovulated) each menstrual cycle during the reproductive years (usually 15 to 45 years) of women. Ovulation is necessary for women to have regular menstrual periods and to become pregnant. Anovulation refers to the condition when this ‘egg release’ does not take place and the menstrual cycles in which they occur are called ‘anovulatory cycles’.

What causes it?

Anovulation can occasionally occur even in healthy fertile women for no reason at all and sometimes for reasons that are not necessarily disease conditions. Anovulation is the norm during pregnancy and is not uncommon at the beginning and end of reproductive life (around the menarche and menopause respectively). The most common reason for anovulation during the reproductive years is ‘polycystic ovary syndrome’. Other causes include excessive blood levels of a hormone called prolactin that blocks ovulation, excessive stress, severe anxiety, extreme physical exertion (as with long distance running), profound weight loss (greater than 15% of body weight), anorexia, serious illnesses and use of certain medication (such as certain antipsychotics).

What problems can it cause?

Pregnancy cannot begin if ovulation does not occur and so the most profound consequence of anovulation is ‘infertility’. Indeed, about a third of all infertility is caused by anovulation. Another consequence of anovulation is that the ovaries do not release sufficient amounts of the female hormones that regulate periods thereby leading to irregular menstrual periods. This hormone imbalance, if persistent over a long period, could increase the risk of osteoporosis (bone loss) and fractures. Research has also shown that over the long-term, anovulatory women who do not achieve the birth of a child may have slightly increased risks of developing cancers of the womb and breast.

How is it detected?

No one of the methods used to test for ovulation in everyday practice is foolproof. The only way of definitely proving that ovulation has taken place is by finding the egg in the woman’s tummy or if pregnancy results. The usual symptoms of ovulation (such as one-sided lower tummy pain and increased amounts of clear vaginal discharge) may become absent in anovulation. Body temperature charting (BBT) may suggest anovulation if the slight increase in body temperature that normally follows ovulation does not occur. Blood or urine hormone tests in the second (luteinising hormone) or third week (progesterone) of the menstrual cycle can indicate ovulation. Ultrasound monitoring (tracking) of the ovaries can similarly indicate ovulation with demonstration of rupture of the mature egg. The usual way we test for adequate ovulation is by measuring the blood levels of FSH and LH during the menstrual period and the levels of Progesterone about seven days before the next period is due.

How is anovulation treated?

The treatment of anovulation aims to restore regular ovulation by various means depending on the cause and the woman’s wishes. This may be achieved by simple measures such as weight gain or loss (in very underweight or overweight women respectively) or reducing the intensity of exercise (for instance in athletes). If fertility is not an issue, it may not be necessary to offer any treatment besides regularising the menstrual periods.

  • Medicines – various medicines are used for the treatment of anovulation including:
  • Regularising the menstrual cycle – to make the woman have regular menstrual periods (may be all that is necessary). This is typically achieved with the combined oral contraceptive pill. Women who cannot use these or do not tolerate them are given other hormone tablets (progestogens) that are typically taken for two to three weeks each menstrual cycle. These tablets generally prevent any bleeding whilst they are being used, allowing menstrual periods to occur only during the tablet-free intervals each cycle.
  • Ovulation induction tablets – this is the first-line form of treatment when fertility is an issue. The first line drug for treating all forms of anovulation is Clomid. Clomid is taken daily for five days starting on the second day of the menstrual period. Women with polycystic ovary syndrome are sometimes also treated with a medicine called Metformin and this is taken every day continuously. Those women who do not respond to Clomid and/or Metformin are sometimes treated by a surgical procedure called ovarian drilling (see below). The doctor will typically confirm that ovulation has indeed occurred by doing a blood test and/or ultrasound scan.
  • Ovulation induction injections – these are typically given daily starting on the second day of the menstrual period and continued for about 10 to 14 days (but sometimes even longer up to 21 days) depending on the woman’s response. It is mandatory that the response to this form of stimulation is monitored by regular blood tests and/or ultrasound scans to reduce the risk of over stimulation. For this reason, this form of treatment can only be administered in properly equipped hospitals.

About three-quarters of treated women will achieve regular ovulation, with about half of these becoming pregnant. Ovulation induction can result in the birth of twins or triplets (up to 1 in 4 women) as well as in a condition of the ovaries called ‘ovarian hyperstimulation syndrome’ (up to 1 in 10 women).

Surgery – this may be used in women with polycystic ovary syndrome and involves drilling a number of holes in one or both ovaries at laparoscopy. It can result in ovulation and pregnancy rates that are similar to those obtainable from the use of medicines.

Women with anovulation who are not wishing to conceive should use appropriate contraception as they could ovulate during some menstrual cycles

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