Transplanting ovarian tissue could be used to delay menopause, research suggests.
- Menopause describes the point in life when the
last menstrual cycle occurs, which happens around the age of 50 in women. Ovarian
reserve depletes in the years, and decades, before menopause occurs.
- Many welcome the end to periods and worries
about unwanted pregnancy, but menopause, and the perimenopause before it,
is often accompanied by troubling symptoms such as hot flashes, cognitive
problems, night sweats, vaginal dryness, anxiety, and a reduced sex drive.
- Now, researchers may have found a way to delay,
and perhaps even prevent, menopause.
- A modeling study suggests that by removing,
freezing, and then reimplanting ovarian tissue, the fertile years can be
extended long beyond the normal age of menopause.
Menopause, which for most women happens between
the ages of 40 and 58, signals the end of the reproductive years. Although the
end of monthly periods and worries about birth control is often welcome, many
people will experience a less welcome range of physical and mental symptoms.
These symptoms, which may include hot flashes, night
sweats, vaginal dryness, anxiety, and a reduced sex drive, can start long
before menopause and continue for several years afterward. So, could a
treatment that delays, or even prevents, menopause be beneficial?
Researchers
at Yale School of Medicine believe that it would and may have found a way to do
it. They suggest that by freezing ovarian tissue taken from a woman during her
reproductive years and then reimplanting it at a later stage, they could delay,
or even prevent menopause.
The mathematical modeling study is published in theAmerican Journal of Obstetrics and
Gynecology.
“This is very interesting
data on the forefront of science-cryopreservation of the ovaries — especially
useful for people undergoing chemotherapy and/radiation for cancer treatment.
These techniques can protect and preserve the ovarian tissue for reimplantation.
The modeling, predicting how long menopause can be delayed is interesting but
not currently useful in practice.”
— Dr Robin Noble, chief
medical officer at Let’s Talk Menopause, speaking to Medical News Today.
Ovarian cortex is the outer part of the ovary, where
most of the follicles — the structures that mature each month to release an egg
at ovulation — are found. For freezing and transplant,
the cortex can be from a donor or from the person undergoing the treatment.
Now, scientists led by Prof. Kutluk Oktay, M.D., Ph.D., have suggested
that the technique could be used to preserve fertility and prevent troubling
symptoms by delaying or even preventing menopause.
The researchers used data from previous studies of
ovarian reserve at different ages, and on how ovarian follicles behave in
ovarian tissue. From this, they created a mathematical model that predicts how
long ovarian transplant surgery might delay menopause in healthy women.
They incorporated several factors, including age and
follicle survival, in their model to see how long different factors might delay
the time of menopause.
How effective is ovarian transplanting?
The model predicted that for most women ages 40 and under,
ovarian tissue cryopreservation and transplant would significantly delay
menopause.
The success of the transplant depended on four
factors:
- Age
at ovarian tissue harvest (21-40 years)
- Amount
of ovarian tissue harvested
- Single
vs. Multiple transplants of harvested tissues
- The
proportion of follicles that survived post-transplant.
Tissue harvested after the age of 40 years did not
delay menopause onset as there were too few viable follicles left in the tissue
of the typical donor.
“The younger the person, the larger number of eggs she
has, as well as the higher the quality of those eggs,” Prof. Oktay said. The
amount of tissue harvested was key — too little and menopause would not be
delayed, but if too much was taken, this might bring on an early menopause.
However, the model accounted for this: “This model gives us the optimum amount
of tissue to harvest for a person of a given age,” he added.
To illustrate their model, the researchers give the
example of a 25-year-old who had 25% of her ovarian cortex tissue harvested,
and then transplanted in one procedure. If 40% of the follicles survived, this
might delay menopause by almost 12 years; if 80% survived, the delay would be
around 15.5 years. Authors noted that currently, ovarian transplant procedures
are associated with a 60% loss of follices and that 80% survival could only be
achieved if technology and techniques progressed in coming years.
However, if they divided up the tissue and
transplanted it in several procedures, menopause delay was increased. At 40%
follicle survival, three transplants extended the delay to 23 years, and six
transplants to 31 years. If 80% of follicles survived, the model predicted that
menopause might be delayed by as much as 47 years, which, for most women, would
mean that they would never experience menopause.
“If we can
adequately replace the hormones (that should continue to improve with more
research into this area), would we want to delay the time of natural menopause?
Many women struggle with issues during their reproductive years — PCOS,
endometriosis, fibroids, painful periods, heavy periods, undesired fertility,
premenstrual dysphoric disorder — would they want to prolong their cycles? I
think not. Would they want to delay or avoid the symptoms of menopause — very
likely. And we can do that with menopausal hormone therapy (MHT) without
exacerbating those other symptoms.”
— Dr. Robin Noble
Menopause is considered a
However, for others, perimenopause and menopause may
mean several years of troubling symptoms that can affect their quality of life.
As we live longer, many women will spend around one-third of their lives
postmenopausal, so they may wish to shorten that time.
Apart from delaying symptoms,
“Do we need cryopreserved ovaries to accomplish these
goals?” Dr. Noble questioned.
“With MHT, we can give back some of these hormones at
various doses, with the option of tailoring to the symptoms and goals of the
person, understanding the risks and benefits of various treatment options.
Moreover, MHT avoids the cyclic symptoms (often bothersome bleeding, mood
changes, bloating, breast tenderness, cyclic migraines) that would be present
in the case of preserved ovaries,” she explained.
But the option of surgery to remove and then replace
cryopreserved ovarian tissue should not be taken lightly, as it does involve
repeated abdominal or keyhole (laparoscopic) surgery. So, a woman would need to
think carefully about whether, for her, the benefits of delaying menopause
outweigh the risks.
Dr. Noble is not convinced that the technique offers
many benefits:
“Menopause is a natural stage of life. It is not a
disease. It is not an illness anymore than aging is an illness. After
menopause, we see significantly increased risks for cardiovascular disease,
bone loss (osteoporosis), diabetes, obesity, colon cancer risks, which seem to
be mitigated with MHT.”
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