An Australian woman who was told she would unlikely ever get pregnant let alone have two healthy twins, has made medical history because the two babies were actually conceived ten days apart.

Kate Hill, who suffered from polycystic ovary syndrome (PCOS) went on hormone treatment in the attempt to get pregnant. The process worked and Kate and her husband fell pregnant but what was most extraordinary was that she was expecting twins although not from the same egg.

In a rare occurrence, she began ovulating again soon after the first pregnancy occurred and conceived a second time ten days later with the remaining sperm from the initial intercourse.

The almost miraculous double pregnancy is called superfetation and has only had around ten cases previously reported in the world.

“I’ve got PCOS and I wasn’t ovulating, so we were not conceiving. We didn’t actually realise how special that was until they were born,” said Kate.

“I ovulated again,” she explained. “Usually a woman doesn’t ovulate again once they fall pregnant with all the hormones, but Charlotte was coming no matter what – she was there.”

“What makes this case even more rare, is that my husband and I only had intercourse one time,” she continued. “His sperm stayed alive for 10 days to fertilize the second egg released.”

The couple now have two healthy ten-month old babies, Charlotte and Olivia who are now termed ‘miracle babies’.

One previous case occurred in 2009, when Julia Grovenburg from Arkansas conceived her daughter and two weeks late fell pregnant with her son.