More twins are being born than ever before but the world may now have reached peak twin, researchers say, the BBC reports.
About 1.6 million twins are born each year worldwide, with one in every 42 children born a twin.
Delayed childbearing and medical techniques such as IVF have seen the rate of twin births rise by a third since the 1980s.
But it could be all downhill from here as the focus shifts to one baby per pregnancy, which is less risky.
According to a global overview in the journal Human Reproduction, the peak was reached because of large increases in twinning rates in all regions over 30 years – from a 32% rise in Asia to a 71% rise in North America.
The researchers collected information on twinning rates from 165 countries for 2010 to 2015, and compared them with rates for 1980 to 1985.
The number of twins born per thousand deliveries is now particularly high in Europe and North America – and worldwide it’s gone from nine per 1,000 deliveries to 12.
But twin rates in Africa have always been high and haven’t changed much over the past 30 years, which could be due to population growth.