Global estimates from the World Health Organization and Guttmacher Institute have found that one in four pregnancies ends in an abortion each year.
The study in the Lancet said 56 million induced abortions take place annually, higher than previously thought.
Researchers acknowledge rates have improved in many rich countries but warn this masks no change in poorer areas over the past 15 years.
Experts are calling for new approaches to contraceptive services. Scientists say the annual number of abortions worldwide increased from 50 million a year between 1990-1994 to 56 million a year between 2010-2014.