POOR OVARIAN RESERVE
BACKGROUND
The ovary is generally thought of as an ‘egg bank’ from which the woman draws during her reproductive life. While each month one egg (oocyte) is released by ovulation; about one thousand additional eggs are lost by destruction. Few if any eggs are replenished during the reproductive years. Thus with advanced maternal age the number of eggs that can be successfully recruited for a possible pregnancy declines. Attempts have been made to assess the number of potential useful oocytes in a noninvasive way.
HOW TO TEST FOR OVARIAN RESERVE
Hormonal Markers
FSH is a hormone secreted by the pituitary gland and indicates the reserve of the ovary. The basal level of Follicle stimulating Hormone (FSH) done on day 1 to day 3 of the period is a better predictor of ovarian reserve than age. The FSH varies from cycle to cycle and thus we can get a variable results in the prediction of ovarian reserve
Ultrasound Markers
Ultrasound of the ovaries which detects the small follicles is an accurate indicator of ovarian reserve. An antral follicle count of less than 5 predicts an unfavorable response.
·This test is dependant on the skill of the scanning person and may differ.
Anti- Mullerian Hormone
AMH is the more accurate test for predicting ovarian reserve The hormone AMH, which is made by the ovarian follicle containing the egg, can tell us how a woman’s ovaries can respond to fertility drugs.
In young women many eggs start to grow each day and quite large numbers reach the final stages of development, where they can respond to fertility drugs. These women have high AMH values. In older women, there are fewer eggs left in the ovary and few will reach these latter stages of development. The blood level of AMH can tell us how many follicles (eggs) are likely be available.
Knowledge of how patients’ ovaries will respond to the hormone injections of a treatment ‘cycle’ is a very important part of fertility treatment. An excessive response to the hormone drugs increases the chances of suffering the dangerous condition of ‘ovarian hyper stimulation syndrome’ (OHSS), while an inadequate response is distressing for patients going through 2 to 3 weeks of daily injections and resulting in no eggs or a sub-optimal number of eggs at egg collection. Both these scenarios are experienced too frequently when we do not know how a patient is likely to respond. Unfortunately, we cannot avoid either of these end-points completely, but we can now use a test to allow us to modify our approach, resulting in a reduced incidence of both.
MODIFICATION OF TREATMENT STRATEGIES
The ovarian assessment allows us to use different treatment strategies for different patients, taking into account their likely response to fertility drugs, thereby increasing treatment safety and pregnancy rates.
When the AMH concentration is high, it indicates a risk of OHSS when traditional treatment methods are used. We can therefore modify our strategy to accommodate this. The AMH test is often increased in polycystic ovarian syndrome, and is beneficial in diagnosing polycystic ovaries from multi cystic ovaries
When the AMH concentration is low, it indicates that the response to traditional treatment methods will be below average, and therefore the chances of success in IVF / ICSI will be reduced. This is common in older women (>37 years), where it is well known that success rates are reduced. However, the predictive value of AMH is considerably better than using a patient’s age.
GENERAL IMPLICATIONS OF LOW AMH VALUE
It is possible for a woman to maintain a normal menstrual pattern for many years after her AMH value is recorded as ‘low’. This is because regular ovulation can be maintained with only a couple of follicles reaching these responsive stages of development each week. However, this is too small a number to allow a response in the number of eggs required for a treatment cycle.
This allows us to use a more individualised treatment regimen which should ultimately result in higher fertilisation and pregnancy rates for selected patients. It should also reduce the cost of treatment for selected patients.