By Keren Zelicha
In recent years, there has been a marked increase in the number of women putting off pregnancy until their late 30s or early 40s. This is the result of many contributing factors including various socio-cultural considerations, among them media coverage of the subject which frequently focuses on the success of older women in becoming pregnant—and in this way, feeding into the general assumption that postponing pregnancy is possible with no price to pay.
In reality, later parenthood has contributed significantly to the rise in infertility and difficulty in conception. This phenomenon, combined with the availability and efficiency of fertility treatment, has led to a growing demand for in-vitro fertility treatment. Some women in their late 30s or early 40s undergoing fertility treatment may occasionally encounter a lack of response to treatment or difficulty developing multiple follicles despite injecting hormones according to the protocol. This situation comes about as a result of low ovarian reserve (a small quantity of eggs remaining). In general, it’s possible to point to the natural trend of gradually increasing FSH levels in women even by their mid-30s. Endocrine changes of this type are in fact already beginning to take place as long as 13 years before menopause. In 1989, Scott reported a prospective research evaluating the connection between high FSH levels and pregnancy rates. As the FSH levels rose, the rates of pregnancy and birth decreased. Further research involving 1,478 women undergoing IVF fertility treatments found that as FSH levels rose, the number of follicles, the number of ova retrieved, the number of embryos, and the percentages of implantation decreased.
There is no single definition today in the medical literature of the term “low ovarian reserve.” There are differences of opinion regarding the importance of certain tests, however it is generally agreed to choose several of them. The most common tests for determining low ovarian reserve are:
- Hormone blood tests
- Rise in FSH levels can be tested between cycle days 3-5
- Low AMH levels (can be tested on any cycle day)
- Low Inhibin B levels can be tested on cycle day 3
- Ultrasound tests
- Low number of antral follicles ( AFC) found on ultrasound at the beginning of the follicular stage
- Low ovarian volume
It is important to point out that these measurements cannot predict the status of the ovarian reserve (number of ova), nor their quality or the chances of pregnancy.
in order to overcome the limitations imposed by lack of universality in definition of poor ovarian reserve ( POR ) in 2011 a working group in Bologna recommend the presence of at least two of the following three features for diagnosis of POR:
Advanced maternal age (≥40 years) or any other risk factor for POR
A previous POR (≤three oocytes with a conventional stimulation protocol)
An abnormal ovarian reserve test (i.e. AFC, 5–7 follicles or AMH, 0.5–1.1 ng/ml)
in addition, women over 40 years of age with an abnormal ovarian reserve test may be classified as “expected poor responders”