More twins are being born than ever and it is due to the increasing use of in vitro fertilization and other assisted reproductive techniques. It is what the first human twinning study, each year 1.6 million twins are born on the planet, a figure that has increased by a third since the the 80’s. “We are seeing levels of twin births that we have not seen before,” said a professor at the University of Oxford in the UK.
Twinning rates have been analyzed in 165 countries in two different periods: from 2010 to 2015 and from 1980 to 1985. The main increase occurred in dizygotic twins, that is, the not identical, twins born from separate eggs. The assisted reproductive techniques, which began in the 1970s, are the main cause of this increase of twins. In contrast, the data barely changed for identical twins, roughly 4 per 1,000 deliveries worldwide.
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