Worldwide, about 1.6 million twins are born every year, making one in 42 newborns part of a baby pair. That is an increase of about 33 percent compared to the 1980s, according to a published earlier this week study from Radboud University, among others, where daily newspaper Faithful writes about.
For the study, information on the birth rates of 165 countries between 2010 and 2015 was collected. These data were bundled with data for the period between 1980 and 1985. “The relative and absolute number of twins being born in the world has never been as high as it is now,” said Jeroen Smits, professor of economic and human development.
The main causes of the increase in the number of twins, according to the researchers, are the increase in fertility treatments and having children at a later age. “Older women get pregnant with twins more often than younger women. We don’t know why, but it is a fact. The chance of having twins increases as the age of the mother increases,” says Smits.
Of the two main causes, the flight taken by fertility treatments such as in vitro fertilization (IVF) is the most important. This was increasingly used in the 1980s and 1990s. “During those decades, multiple embryos were often inserted into the woman’s womb, increasing the chance of twins being born.”
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