Braga was to present the findings Tuesday during the 20th World Congress on Fertility and Sterility in Munich, Germany.
Not everyone is convinced that seasonal differences are present for IVF, said Dr. David Keefe, chairman of obstetrics and gynecology at the NYU Langone Medical Center in New York City. He even suggested that women might be risking their fertility even further if they try to wait for what might be perceived as a more fertile time of the year.
"First, when we do in vitro, we're already overriding the whole system and the hormones that turn on reproduction. And, second, species that have a longer gestation, such as humans, have typically bred when the days are getting shorter, and they [the study authors] found the opposite here," explained Keefe.
"In addition, humans aren't as controlled or hardwired to environmental changes any more. We live in artificial lights, and control the temperature and humidity, so many cues that would trigger breeding, we control all the time. We've insulated ourselves against environmental changes," he said.
Plus, Keefe noted, the Brazilian researchers only studied one year, and it's possible that for other years, fertilization rates may be different by the season.
But, what's most important for people considering IVF is that there were no differences between seasons in the pregnancy rates, and that's what really matters to someone who's trying to have a baby.
Even Braga doesn't recommend waiting for the perfect season. "Despite the better results obtained in spring, it is important to highlight that assisted reproduction techniques are effective regardless of the season in which the treatment is being performed," she said.
Learn more about in vitro fertilization from the U.S. National Library of Medicine.
SOURCES: Daniela Braga, M.S.,
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