The number of twins born in Europe soared by 61% in 30 years, according to research.
Fertility treatments, older motherhood and the pill are fuelling the phenomenon, say scientists.
Around 1.6 million twins a year arrive worldwide every year…one in every 42 infants.
The rate has risen a third since the 1980s – from nine to 12 per 1,000 deliveries.
In Europe it’s increased from nine to 14.5 – or 61 percent.
A major cause is the growth in medically assisted reproduction (MAR) – including IVF (in vitro fertilisation), ovarian stimulation and artificial insemination.
Delayed childbearing – a trend seen in the UK and many other countries – is another factor. The likelihood of twins increases with a mother’s age.
Professor Christiaan Monden, of the University of Oxford, said: “The relative and absolute numbers of twins in the world are higher than they have ever been since the mid-twentieth century and this is likely to be an all-time high.
“This is important as twin deliveries are associated with higher death rates among babies and children and more complications for mothers and children during pregnancy, and during and after delivery.”
The study published in Human Reproduction is the first comprehensive global analysis of its kind.
It was based on data on twinning rates from 165 countries between 2010 to 2015 – covering 99 percent of the world’s population.
This was compared to the same information the researchers were able to obtain for for 112 countries from 1980 to 1985.
Celebrity mothers of twins include Angelina Jolie, Julia Roberts, Beyonce, Jennifer Lopez, Celine Dion and Mariah Carey.
The increase was 71, 61 and 32 percent in the US, Europe and Asia, respectively.
Fertility treatments started in wealthier countries in 1970s. They spread to emerging economies in Asia and Latin America in the 1980s and 1990s and some parts of South Asia and Africa after 2000.
The researchers plan to update their results with data for the early 2020s to see if twinning rates have started to decrease in high income countries.