Two weeks after Adriana Rodriguez from Bellingham, Washington gave birth to her third child, she suffered a tear in her coronary artery – known in medical terms as a dissection. These dissections are thought to be brought on by stress and hormonal changes during pregnancy, and they usually heal without a major impact to the mother with the help of medication after the delivery.

In Rodriguez's case though, the tear progressed to serious heart failure that did not respond to the medication or even more aggressive treatments. She eventually wound up on a machine called an extracorporeal membrane oxygenation system (ECMO) that takes over the role of the heart and lungs in pumping and oxygenating the body's blood supply. Patients on this machine can usually only come off it after they get a transplant.

But, because Rodriguez had been pregnant, doctors determined that her body was 99% likely to reject a donor heart.