How can we assess ovulation (egg release)?

If you are seeing your periods on a reasonably regular monthly cycle, without hormone treatment, there is a very good chance that you are ovulating; a regular cycle does not, however, guarantee this. No test, other than a positive pregnancy test, can provide absolute evidence that you have ovulated.

 Anovulatory (eggs are not being released) infertility is suggested by amenorrhoea (absent periods -amenorrhoea), oligomenorrhoea (infrequent periods - Q6.2) or irregular menstruation.

Many women experience a change in their vaginal discharge just before ovulation, the mucus becoming more watery and stretchy. Mid-cycle pelvic pain usually indicates ovulation.

A basal temperature chart provides a simple and inexpensive early indication of ovulation. The temperature can be taken by mouth with a regular thermometer that should be easy to read. The clinic nurse can teach you how to use this instrument. The temperature should be taken before the day's activity begins. Typically, the temperature falls and then rises by 0.5 degrees centigrade around the time of ovulation. Sexual intercourse should be recorded on the chart as this may show that timing of intercourse may be inappropriate in relation to ovulation. The temperature remains elevated through the luteal phase (second half of the cycle) as a marker of progesterone activity (Fig.2.3). The rise of the temperature in association with ovulation is apparent only retrospectively and couples should appreciate that it is not a useful predictor of imminent ovulation. A sustained elevation of the temperature in association with failure to menstruate is usually diagnostic for pregnancy. The popularity of the temperature chart has fallen as other tests seem more accurate.

Home testing for the LH surge (menstrual cycles

  • Q6.11) provides a valuable method for determining the timing of ovulation, potentially reducing stress and costs of fertility treatments. These ovulation predictor tests are available from your local chemist.

    A blood test for progesterone level is a useful guide to ovulation. The test should be taken between four and ten days before a period (day 21 is perfect for a 28 day cycle). A result in excess of 30 nmol/l is generally accepted as evidence of ovulation. There is a suggestion that slightly higher levels of progesterone should occur in patients taking clomiphene or tamoxifen.

    Ultrasound (pelvic ultrasound) has found an important role in the investigation and treatment of infertility. An initial single ultrasound evaluation of the pelvis on the twelfth day of your cycle provides a useful assessment of your ovaries and uterus. At this time there should be a dominant follicle of at least 12 mm in a twenty eight day cycle and the endometrium should be well developed with adequate oestrogenic activity. A series of ultrasound examinations (follicle tracking scans) from about the sixth day of your cycle will chart egg (follicular) development and release.

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