Since the birth of Louise Brown in July 1978, five million babies have been born with the help of IVF and other assisted reproductive technologies (ART).
At least one-third of these children were conceived in the last six years, according to a report compiled by the International Committee for the Monitoring of Assisted Reproductive Technology (ICMART).
The number of children conceived using IVF, surrogacy and egg donation and freezing climbed from around 90,000 in the 1990s to an estimated 2.5 million in 2007. Since then, an additional 1.5 million births have resulted from ART.
'The number of babies born through ART is now about the same as the population of a US state such as Colorado, or a country such as Lebanon or Ireland', said Dr Richard Kennedy, secretary general of the International Federation of Fertility Societies. 'This is a great medical success story'.
The increase is thought to be based on a range of factors, including reduction in stigma and improvements in success rates. The rising birth rates are also in part due to better access to technologies in developing countries, and improved reimbursement or insurance coverage.
The figure was calculated using data on ART from 74 countries. However, the researchers had to account for missing years and make approximations for other countries who had not published any data. This includes China, where an estimated 900,000 babies have been born using assisted conception.
'There is so much missing data, which is the reason this hasn’t been done until now', Dr David Adamson, who conducted the research, told USA Today. 'The reality is no one will ever know exactly how many babies have been born because no one ever counted'.
Initial results from this research were published in July 2012 (as reported in BioNews 663). The final report was presented at the American Society for Reproductive Medicine's annual conference and appeared in the journal Fertility and Sterility.