The ovary is generally thought of as an egg bank from which the woman draws during her reproductive life. While each month one egg is released by ovulation about one thousand additional eggs are lost by atresia. Few if any oocytes 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.
The most commonly used test to assess this ovarian reserve is the day 3 FSH test. This blood test determines the level of FSH on cycle day 3. Cycle day 3 is chosen because at this time the estrogen level is expected to be low, a critical feature, as FSH levels are subject to a negative feedback. Thus any determination of FSH needs to include the corresponding estradiol level to indicate that the FSH level was drawn, when the estrogen level was low. In a patient with infrequent menstruation, an FSH level and estrogen level could be measured at random and is valid if the estrogen level is low. Generally FSH levels are expected to be below 10 miu/ml in women with reproductive potential (levels of 10-15 miu/ml are considered borderline). A clomiphene challenge test is a variation on this approach.
Another approach is to examine the ovaries by gynecologic ultrasonography and to determine their size as ovaries depleted of eggs tend to be smaller and to examine the number of antral follicles visible by sonography.
Prediction of ovarian reserve based on day-3 serum follicle stimulating hormone concentrations during the pituitary suppression cycle using a gonadotropin releasing hormone agonist in patients undergoing in vitro fertilization-embryo transfer
Jun 01, 2004; Key words: OVARIAN RESERVE, FOLLICLE STIMULATING HORMONE, GONADOTROPIN, IVF-ET, OHSS ABSTRACT Satisfactory results following in...