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Latest Surrogacy News
Fewer Women Having
Triplets or More
Fewer embryo transfers and
improving IVF technology cited
By Serena Gordon
HealthDay Reporter
 April
14, 2004
WEDNESDAY, April 14 (HealthDayNews)
-- The average number of embryos transferred during an
in vitro fertilization attempt has decreased since the
late 1990s, and in turn, so has the rate of pregnancies
with three or more babies.
In a new study
appearing in the April 15 issue of the New England
Journal of Medicine, researchers report the average
number of embryos transferred began decreasing sharply
in 1997, after the American Society for Reproductive
Medicine (ASRM) issued guidelines for embryo transfers.
Not surprisingly, the researchers also found the number
of triplets and higher pregnancies also steeply declined
during that time.
"We found improving
trends in terms of the average number of embryos
transferred and a significant reduction of triplets and
higher-order pregnancies," said study co-author Dr.
Tarun Jain, a clinical fellow in reproductive
endocrinology and infertility at Brigham and Women's
Hospital at Harvard Medical School in Boston. "There's a
correlation with the enaction of the guidelines and the
improving trends. Right after 1998, the high-order
pregnancies with triplets or more dramatically flattened
out. Prior to that, they were rising exponentially."
In vitro fertilization,
commonly known as IVF, has been available to infertile
couples in the United States since 1981. Before
attempting IVF, women first undergo hormone treatment so
they produce multiple eggs. The eggs are harvested, and
then placed in a petri dish, where they are mixed with
sperm. If an egg is fertilized and begins dividing, it
is considered an embryo. One or more embryos are placed
into a woman's uterus, with the hope that the embryo
will implant and a normal pregnancy will occur.
Because the procedure
is time-consuming, emotionally difficult and expensive
-- the cost averages more than $12,000 per attempt --
multiple embryos are usually transferred. But when
multiple embryos are transferred, multiple gestation
pregnancies can occur, often with triplets or more.
Complication rates for
multiple pregnancies are much higher than they are for
singleton pregnancies. According to the ASRM, mothers
pregnant with multiples are more likely to deliver
early, develop preeclampsia, have placental
abnormalities, develop gestational diabetes, need a
Caesarean or have an underweight baby with disabilities.
These complications,
along with the rising rate of multiple pregnancies, are
the reason ASRM, in conjunction with the Society for
Assisted Reproductive Technology (SART), developed
guidelines, originally issued in June 1997.
The guidelines
suggested women with an above-average chance of a
successful IVF procedure should have no more than three
embryos transferred during any attempt. Above average
was defined as women under 35 whose eggs hadn't been
frozen. The recommendation for women with an average
prognosis (between 35 and 40) was no more than four
embryos at any one try, and for women with a
below-average prognosis (those over 40 or who had
several failed prior attempts), no more than five.
For this study, Jain
and his colleagues analyzed data from the U.S. Centers
for Disease Control and Prevention for 1995 through
2001. Outcome information on assisted reproduction
attempts is reported to the CDC by fertility clinics.
The researchers also included data on the number of
multiple births from the National Center for Health
Statistics.
According to the study,
the number of embryos transferred started decreasing in
1997, but the largest drop -- 11 percent -- occurred
during 1998 and 1999. The number of twin births didn't
change significantly during this time, but triplets and
higher pregnancies started to decrease around the same
time. The sharpest decline -- 21 percent -- occurred
between 1998 and 1999.
"A couple seeking
treatment for infertility should be encouraged by these
findings," says study co-author Dr. Mark Hornstein,
director of the division of reproductive endocrinology
at Brigham and Women's. "We're doing a better job. The
same programs are establishing more pregnancies and less
multiples."
Hornstein says the
guidelines may have contributed to the decline, but also
cites improved technology as a reason.
Dr. Jamie Grifo,
director of the division of reproductive endocrinology
at New York University Medical Center and past president
of the Society for Assisted Reproductive Technology,
agrees. "A lot of us started working on this before the
guidelines," Grifo said. "This study demonstrates that
we're getting better because the technology allows us to
select better and fewer embryos." He added this study
also demonstrates that government regulations aren't
necessary for the assisted reproduction field.
"We're all working on
this," said Grifo. "Ideally, IVF should get to the point
where we can put one embryo in, but right now, success
rates are in proportion to how many embryos are
transferred." And, Grifo noted, because of the effort
and expense involved, most patients want more than one
embryo to be transferred.
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