"IVF has become sort of mainstream," says Dr. David Adamson, a reproductive endocrinologist in San Jose and Palo Alto, Calif., who led the efforts to analyze 10 reports from two international organizations that monitor births resulting from fertility treatment.
Until now, it's been hard to get a handle on the number of IVF births worldwide, said Adamson, who is part of a nongovernmental organization called ICMART, or the International Committee for Monitoring Assisted Reproductive Technology.
The reports spanned the years from 1989 to 2007, with a few years missing in between. They relied on available data, which is far from complete, meaning that 5 million births is really a "best guess," says Adamson.
Researchers are relying on data that assumes they have information on two-thirds of reported IVF cycles worldwide. The figures in the 10 reports come in part from the International Working Group for Registers on Assisted Reproduction, a volunteer group of physicians that banded together in the late 1980s to begin collecting IVF data. About 10 years ago, that organization evolved into ICMART, which has continued to collect information about IVF births.
"There is so much missing data, which is the reason this hasn't been done until now," says Adamson. "The reality is no one will ever know exactly how many babies have been born because no one ever counted."
There are nearly 200 countries in the world, and Adamson estimates that about half have at least one IVF clinic. But just 74 countries have ever tracked and shared their data, and they don't all do so consistently. China, which is thought to account for close to 20% of IVF births, doesn't report its data, although Adamson said the Ministry of Health has indicated it's working toward that goal.
Births have increased exponentially over the years, according to the research. In 1990, a little more than a decade after the first IVF birth, about 95,000 babies were born. By 2000, that figure had grown to nearly 1 million, and by 2007, it had climbed to more than 2 million.
"A lot of this has to do with increased success rates," says Dr. Robert Stillman, medical director emeritus at Shady Grove Fertility Center in Rockville, Md., which says it performs more IVF cycles than any other U.S. clinic. "There has been a steady improvement in the ability to culture embryos and improve pregnancy rates. A 38-year-old coming to us in 1997 versus 2007 versus 2013 has a very different prognosis."
Image: Fertility lab, via Shutterstock