PRAGUE, Czech Republic, June 21 (UPI) -- An Australian researcher says that the in vitro fertilization is not the only reason for an increase in twins -- improved nutrition is also a factor.
"Over the last 100 years, both in Britain and Australia, there has been an increase in identical twinning through the division of the embryo into two, even without IVF," said Robert Jansen, medical director of Sydney IVF. "With the move to single embryo transfer with IVF this trend is obviously set to continue."
The present rate of identical twinning with IVF is between one in 100 and one in 150, a little more than twice the rate involved when getting pregnant naturally, according to Jansen.
The study shows for the first time that the increase in the birth of twins coincides with improving cultural conditions and that it started before any manipulation of the human egg, says Jansen.
"Therefore transfer of just one fertilized embryo can therefore still lead to twins," said Jansen.
The findings were presented at the 22nd annual conference of the European Society of Human Reproduction and Embryology in Prague, Czech Republic.
