There has been a debate going on amongst IVF experts for a long time.
It boils down to this question: do women with decreased ovarian reserve have less eggs only?
Meaning the quality of the eggs is normal?
Or do they have worse egg quality too?
A new study may have finally answered that question.
Stay tuned
Women produce all of the eggs they are ever going to have in their lives before they are
born.
Over time, the eggs degenerate so older women on average have less eggs remaining in their
ovaries compared to younger women.
Fertility experts call this ovarian reserve.
Women with decreased ovarian reserve have lower success rates with fertility treatments
like IVF.
They tend not to respond to fertility medications very well so they end up getting less eggs
and therefore less embryos.
There are several different ways that fertility doctors can attempt to estimate a woman’s
ovarian reserve.
First, there are the blood tests.
Women who have low AMH levels or high FSH levels, have decreased ovarian reserve.
Second, there is ultrasound.
Doctors can count the number of small follicles in the ovaries.
A low follicle count indicates decreased ovarian reserve.
Another method is to look at how a woman responds to fertility injections during IVF.
Women who produce less eggs also have decreased reserve.
Many doctors use a set of criteria known as the Bologna Criteria in which at least two
of the following is present: 1) abnormal ovarian
reserve test; 2) previous poor ovarian response in a previous IVF cycle; or 3) female age
over 40 or other risk factors for poor reserve.
The main difficulty IVF experts have had in separating quantity and quality is age.
As women get older, they are more likely to have less eggs but they are more likely to
have poorer quality eggs.
What we need to do is control for age.
In other words, we need to find a group of younger women, all of the same age, but with
some who have decreased reserve and some who have normal reserve.
The second problem is defining egg quality.
A very objective way to do this is to look at how often women produce embryos with chromosome
abnormalities.
We know, for example, that as women age, they produce more embryos with chromosome abnormalities.
Back in 2001, researchers performed a small study and determined that women with high
FSH levels were more likely to have a baby with Down’s syndrome which is the most common
chromosome abnormality in live born babies and women with normal FSH levels were less
likely to have a Down’s baby than you would expect just looking at age.
In 2012, researchers looked at 370 couples and divided them into decreased reserve and
normal reserve groups based on their AMH and FSH levels
This year, doctors looked at over 1100 women who did IVF with PGT which is testing of the
embryos to look for abnormalities.
About 20% of the women had decreased reserve using the Bologna Criteria.
As expected, the women with decreased reserve produced less eggs and less embryos.
However, they also produced less normal embryos.
In fact, after controlling for age, they found that women with decreased ovarian reserve
had 23% less normal embryos than women with normal ovarian reserve.
They also looked at the group of women at age group who produced the lowest number of
eggs and compared them to those getting a higher number of eggs.
Again they found that the low reserve group produced less normal embryos.
Was there any good news?
Yes.
women with decreased reserve who were lucky enough have a normal embryo for transfer,
had the same pregnancy rates and miscarriage rates as women with normal ovarian reserve
Our InfertilityTV bottom Line is this.
Women with decreased ovarian reserve have less eggs and they also are more likely to
have poor quality eggs as measured by a 23% higher likelihood of producing embryos with
chromosome abnormalities.
Once you have normal embryos for transfer, however, the pregnancy rates are just as good
as they are for other women