Why does age affect fertility?
A woman’s own ability to get pregnant tends to decrease as she gets older. As age increases, women have fewer eggs, egg quality diminishes, and eggs will have a higher rate of abnormalities in their genetic material (chromosomes). All these factors together explain why older women have lower pregnancy rates and higher rates of miscarriage.
The ability to conceive decreases in all women as age progresses, but the exact age when a woman can no longer conceive varies considerably amongst women. In some, this may happen at a younger age than would normally be anticipated. Current scientific data suggest that approximately one third of couples will encounter problems getting pregnant when the female partner is age 35 or older.
What does ‘ovarian reserve’ mean?
The term ‘ovarian reserve’ refers to the total number of healthy eggs in the ovaries. It is important to know that all women are born with their entire ovarian reserve. In other words, the ovaries do not produce more eggs during a woman’s reproductive journey. Instead, each month the ovaries recruit a number of eggs to grow from the existing pool. One of these eggs dominates and is subsequently released while the remaining of the recruited eggs become inactive. As it is not possible to count the exact numbers of eggs inside the ovary at any given time, we use certain tests which rely on the levels of hormones these eggs produce or their appearance on ultrasound. These tests are consequently known as markers of ovarian reserve.
What are the usual blood tests of ovarian reserve?
The commonest way to test ovarian reserve is by performing a blood test to measure certain hormone levels. Follicle-stimulating hormone (FSH) and estradiol are checked at the beginning of the menstrual cycle. This can be done on cycle day 2 or 3, but it can actually be performed between day 1 to 5. These hormone levels can give us essential information about how the ovaries and pituitary gland are co-operate to help release an egg each month.
The pituitary gland is situated in our brain and produces FSH to stimulate a follicle grow. A follicle is a small fluid-filled cyst that contains one egg each. The FSH levels are at their lowest level in the start of the menstrual cycle and then increase gradually, helping the follicle to grow the egg to mature. As this occurs, the follicle releases a hormone called estradiol. Subsequently, the rising levels of estradiol communicate signals to the pituitary gland to produce less FSH. In general, women with high day-3 levels of FSH and/or estradiol are less likely to produce the optimal number of eggs during IVF treatment.
What is the most accurate blood test to measure the ovarian reserve?
Antimüllerian hormone (AMH) is now regarded as the most accurate blood test of ovarian reserve. AMH is produced by the follicle. Consequently, the blood level of AMH is directly related to the number of available eggs. This blood test is not only accurate but also practical as the AMH can be tested at any time during the menstrual cycle.
It is important to note that laboratory procedures for this test and “normal” levels vary significantly from lab to lab. The result of the AMH therefore needs to be interpreted together with Dr. Christopoulos, who will help you understand precisely what these results mean for your individual case.
Antral follicle count
A transvaginal ultrasound is usually performed the early part of the menstrual cycle to count the number of small ovarian follicles measuring between 2 to 10mm. These are called antral follicles and their number conveys information on how many eggs are available to respond to IVF medication. This test is only accurate when it is done by a highly-skilled and experienced IVF specialist. Dr. Christopoulos has immense experience in ultrasound techniques, the assessment and the accurate interpretation of the antral follicle count and the relevant blood results.
Previous Response to gonadotropins
Gonadotropins are hormone injections that are given to stimulate the ovary to grow multiple eggs at once during IVF treatment. Higher doses of gonadotropins are usually required to help with the stimulation of eggs as the ovarian reserve decreases.
If you have had previous fertility treatment, the technical details of the treatment will be reviewed meticulously by Dr. Christopoulos. The type, dose, timing and duration of use of gonadotropins will be studied carefully. This will help identify which changes are indicated to provide the optimal outcome during further fertility treatment.
Do the tests of ovarian reserve assess the quality of the available eggs?
It is a common misconception that the blood and ultrasound scans of ovarian reserve reflect on the quality of the eggs as well. This is not the case. We have extensive and convincing studies published in high-impact medical journals such as the New England Journal of Medicine, which prove that women of similar age and different AMH levels have the same chance of spontaneous conception. The results of these investigations –therefore- need to be interpreted together with a specialist as they highlight the expected response to fertility treatment and inform the specialist on which individual fertility treatment would suit you best.
Please contact with Dr. Christopoulos if you are planning to undergo ovarian reserve testing or if you wish to discuss how your results may affect your chances of conception.