June 15 Women preparing for fertility treatment
get a series of daily, sometimes uncomfortable, hormone shots to
kick their ovaries into overdrive, but a European review of
previous studies suggests that one long-acting shot may work
just as well.
In an analysis of four past studies including over 2,300
women with infertility, researchers found the women were just as
likely to get pregnant - and didn't have any more complications
- when they got a single, long-acting dose of
follicle-stimulating hormone (FSH).
For in vitro fertilization, extra FSH is used to trigger the
ovaries to grow and release multiple eggs, which are then
fertilized outside the body and transferred to the uterus.
"Long-acting FSH (weekly injection) is a good and safe
alternative to daily injections in the first week of ovarian
stimulation for IVF," said Jan Kremer from Radboud University
Nijmegen Medical Center in the Netherlands, who worked on the
The long-acting shot is used in Europe but not currently
available in the United States, because it hasn't been approved
by the Food and Drug Administration.
The findings, published in The Cochrane Library, cover 2,335
Of that number, 987 got daily FSH shots for a week and 1,348
had one long-acting shot at a range of doses, along with the
usual course of other IVF hormone injections.
In studies that used the lowest dose of the long-acting
hormone, between 60 and 120 micrograms - fewer women in the
one-shot group got pregnant than in the daily FSH comparison
However, at slightly higher doses - 150 to 180 micrograms -
pregnancy and birth rates didn't suffer: 343 of every 1,000
women getting one long-acting shot had a baby, compared to 336
out of 1,000 in the daily-shot group.
The long-acting shot didn't seem to come with a higher risk
of miscarriage, having twins or developing a pregnancy-related
complication, including swollen ovaries.
The main advantage of the single shot is convenience, said
Samuel Pang, medical director at the Reproductive Science Center
of New England in Lexington, Massachusetts.
FSH shots are simple injections that women can give
themselves, similar to insulin, but the process can still be
difficult for some.
"In my mind, based on the studies that have been done and
based on my own experience, it is a safe and effective product,"
said Pang, who wasn't involved in the new study, to Reuters
"The only caveat is it really needs to be used in
Like Kremer, he cautioned against using the long-acting shot
in women who are unlikely to respond to the hormone, or those
who may over-respond.
A week after getting the long-acting shot, many women still
need a few daily injections of FSH before they're ready to have
their eggs harvested, he added.
Pang worked on research that has been submitted to the FDA
on the hormone shot, but says it's at least a year or two away
from being available in the United States.
(Reporting from New York by Genevra Pittman at Reuters Health;
editing by Elaine Lies and Bob Tourtellotte)