Diminished Ovarian Reserve can be successfully treated in our Austin, Tx Fertility Clinic
Diminished ovarian reserve
refers to a clinical situation in which the ovary
does not contain as many oocytes as would be
expected for a woman’s age. It is difficult to
adequately stimulate (or “superovulate”) a woman’s
ovary in the presence of diminished ovarian reserve.
Superovulation increases the chance of conception in
a treatment cycle by causing more oocytes to ovulate
– thereby leading to a better chance for potential
fertilization. If it is difficult to stimulate a
woman’s ovary, there is limited ability to increase
the chance of achieving pregnancy.
Women develop all of their oocytes before
they are born. In fact the number of oocytes that a woman has peaks
approximately twenty weeks before she is delivered from her mother’s
uterus. At that time, there are 6-7 million oocytes within the
ovary; this number declines rapidly from that point forward such
that by the time she reaches puberty there are only approximately
500,000 oocytes remaining. As a woman proceeds through a natural
cycle at any point in her reproductive life, approximately 300
oocytes try to develop to the point of ovulation. However, usually
only one “dominant follicle” releases its oocyte. The remaining
oocytes that do not ovulate become atretic, or regress and get
absorbed back into the ovarian tissue. The process repeats itself in
each subsequent cycle. The rate of loss of oocytes within the ovary
is genetically predetermined. Some women will experience a
significant decline in the quantity of their oocytes in their
forties, while others may experience this much earlier. Those women
who experience premature decline are considered to have diminished
ovarian reserve.
Although genetically predetermined loss of
oocytes is the most common cause of diminished ovarian reserve,
there are other causes as well. Most of these are covered in our
website section on premature ovarian failure. In fact, for women
under 35 years of age, diminished ovarian reserve is a precursor of
premature ovarian failure.
Diminished ovarian reserve can also result
from the consequence of the ovary having been damaged or destroyed
from disease processes. One of the most common diseases is
endometriosis. Other types of benign ovarian tumors and even
borderline malignant tumors of the ovary can also destroy ovarian
tissue. Surgical removal of ovarian disease frequently results in
the removal of some normal ovarian tissue, as well. It is also not
uncommon for women to lose an ovary from surgery for a fallopian
tube problem and/or a surgery for a benign ovarian problem. In
addition to the above described conditions, ovarian tissue may also
be destroyed by an autoimmune process in which antibodies attack the
follicles that contain oocytes within the ovary.
There are several recommended ways to
evaluate a woman’s ovarian reserve. These tests are an important
part of the fertility evaluation in some patients as it is possible
for women to have diminished ovarian reserve and still have regular,
ovulatory cycles. A basal antral follicle count is one of the most
reliable tests for evaluating ovarian reserve. A transvaginal
ultrasound examination is performed in the first few days of the
woman’s cycle and the number of small, resting follicles is
counted. In general, if there are at least 8-9 resting follicles
the patient is considered to have normal ovarian reserve. A more
common way to evaluate a woman’s ovarian reserve is to obtain serum
FSH and serum estradiol on cycle day #2, 3, or 4. The FSH level
should be less than 10-12 miu/ml. An FSH greater than 18 miu/ml
suggests a significant reduction in ovarian reserve with a
corresponding marked reduction in the chance of achieving pregnancy,
even with advanced fertility treatment.
A “gray zone” of ovarian reserve is
sometimes defined as a serum FSH between 12 and 17 miu/ml. It is
important to have a serum estradiol performed at the same time as
the FSH level. If the estradiol is under 50, which is considered
normal, then the FSH level is more accurate. If the estradiol level
is over 50, the FSH level might be artificially suppressed by the
elevated serum estrogen level and therefore be less accurate. Also
if the serum estradiol is over 50, this is considered to be abnormal
and indicative of diminished ovarian reserve. Although patients
with diminished ovarian reserve usually do not respond well to
superovulation, there are certain superovulation protocols that may
allow patients to respond better and increase their chance of
conceiving. If the diminished ovarian reserve is so significant
that a woman cannot respond to superovulation, her best option for
achieving pregnancy is to undergo a cycle of in vitro fertilization
using donor oocytes.
Ovarian reserve testing is a reflection of
the quantity of oocytes within the ovary more than a reflection of
quality – although many investigators believe that these two
characteristics are closely related. Despite the widespread use of
ovarian reserve testing, it appears that age is still the most
important predictor of oocyte quality.
Diminished ovarian reserve does not
eliminate the possibility of pregnancy. However, this problem should
encourage a woman to be more aggressive in her quest to become
pregnant as time is clearly of the essence.
