A New Jersey woman has become the first mother in the world to give birth to healthy twin daughters only months after receiving a heart transplant.

Stefania DeMayo, 29, was still recovering from her life-saving transplant when she and her husband Richard, 35, found out she was pregnant, the Daily Mail reported.

Doctors warned the couple that a pregnancy would put Stefania’s life in serious danger.

“They said being pregnant would place too much strain on my heart,” Stefania said.

Stefania suffered from restrictive cardiomyopathy, a rare condition where the heart chambers are stiff and unable to properly fill with blood.

After three years of waiting for a heart, Sean Clegg, a 14-year-old boy who was killed by a car while riding his bike, was a donor match.

After the operation, Stefania was allowed home and counseled against getting pregnant for at least a year.

Despite warnings, the Stefania gave birth to twins Melania and Natalia after 7 months of pregnancy.

Very few women have given birth after a heart transplant, and never to a set of twins.

Doctors said Stefania was the most high-risk pregnancy they had ever treated.

Pre-natal testing showed that the twins did not show signs of Down syndrome, but had developed twin-to-twin transfusion syndrome, a condition where one baby takes most of the nourishment being provided in the womb.

“They thought both babies would die or I would have to abort the smaller baby to save the other,” said Stefania. “It was devastating. I couldn't bear it.”

Today, both twins and mother are home and healthy after their long battle. Even though the DeMayos have been assured the worst is over, Stefania has not forgotten the reason why she and her husband were able to become proud parents.

“Thanks to Sean Clegg, who gave me his heart, there are now three people living that wouldn't be here without him,” she said.

Click here to read more from the Daily Mail.