In women, eggs are produced even before she is born. Eggs are not produced during her lifetime and eggs are only recruited every month. Only one egg is released every month and the rest of the eggs are not useful as they die in that month. Egg reserve keeps going down as the age increases and more significantly after the age of 35.

Ovarian reserve tests predict how a woman having fertility treatment would respond to the drugs used to stimulate the ovaries and ultimately how many eggs she may produce.

Refer to Figure -1

Ovarian reserve can be assessed through blood tests to measure two important hormones: Follicle stimulating hormone (FSH) and Anti-Müllerian Hormone (AMH) or Antral Follicular Count(AFC)by an ultrasound scan that counts the visible follicles within each ovary.

FSH is produced by the brain and travels through the blood stream to the ovaries where it stimulates the growth of follicles. A normal FSH level is between 2-8mIU/ml.  This is enough to support the growth of one follicle and is how nature normally limits us to singleton pregnancies. As FSH levels vary through the cycle it must be measured in the first few days of menstruation (day 2-4 of the cycle).

AMH is produced by the growing follicles and is a direct marker of the number of follicles. AMH varies with age but normal levels are somewhere between1.5 – 4 ng/ml. Lower levels are indicative of poor reserve and higher levels associated with but not diagnostic of polycystic ovaries. AMH varies less through the cycle and so can be measured at any time.

Antral follicular Count (AFC):The growing follicles can be seen on ultrasound. During the scan, which has to be an internal scan because the follicles are so small, the follicles are counted and you are given a total antral follicle count.

The AFC and AMH correlate better each other with regards to the ovarian reserve. AMH and AFC can provide some information about egg numbers are better markers of ovarian reserve than FSH. However, a raised FSH level (≥8) is important as it does correlate with a poorer response to ovarian stimulation. AMH declines earlier than the rise of FSH when the ovarian reserve is declining.

Age is, however, the ultimate marker of ovarian reserve. In general, older women with good reserve are likely to do less well in IVF than younger women with poor reserve. However, for women of the same age or women within specific age groups such as under 35, 35-37 and so on, ovarian reserve tests provide extra information and do differentiate how they will respond in IVF.

Refer to Figure – 2

It is important to remember that these tests were developed to inform about fertility treatment and not your natural fertility.

Many women with low ovarian reserve will conceive without any problems whilst others with a good ovarian reserve may take time and need fertility treatment.

Their increasing use as an ovarian reserve test is to reassure women that their fertility is normal or that they should consider treatment sooner rather than later is open to interpretation.

There is no doubt that tests showing a good ovarian reserve are reassuring but they by no means guarantee a baby and equally a poor or impaired ovarian reserve does not mean you will struggle.

ABOVE TESTS ON OVARIAN RESERVE TELLS US ABOUT THE QUANTITY (NUMBER) OF EGGS LEFT IN THE OVARIES BUT NOT THE QUALITY OF EGGS.

OVARIAN RESERVE TEST RESULTS DO NOT INDICATE ABOUT THE QUALITY OF THE EGGS OR ABOUT THE CHANCES OF GETTING PREGNANT.

IN WOMEN WITH LOW OVARIAN RESERVE, AMH & AFC WILL BE LOW AND FSH VALUE WILL BE HIGH.