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 study.
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 women.
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 group.
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 Health.
"The only caveat is it really needs to be used in well-selected patients."
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. SOURCE: bit.ly/LFupNY (Reporting from New York by Genevra Pittman at Reuters Health; editing by Elaine Lies and Bob Tourtellotte)