An Ohio mother got an incredibly rare gift this Mother's Day. Not diamonds or flowers, but a very special set of twins.

​​"The ultrasound tech said 'Oh, there's two' and my husband said, 'Two what?' The couple was told they were having mono-mono twins, meaning the babies shared the same amniotic sac and placenta. The odds of this type of pregnancy? One in 10,000 births." (Via WEWS)

Sarah and Bill Thistlethwaite's baby girls came into the world not just happy and healthy, but also holding hands. (Via WEWS)

The survival rate for monoamniotic, or mono mono, twins is anywhere from 81-95 percent with aggressive fetal monitoring, but that number can drop to 50 percent without such monitoring.

Because the babies share the same amniotic sac, there's a risk of the babies becoming entangled in each others' cords, one twin compressing the other's cord, or one twin receiving more nourishment than the other. (Via Wikipedia)

And there aren't many treatments. A drug called Sulindac has been used experimentally to lower the amount of amniotic fluid inside the sac which makes it harder for the twins to move around, potentially preventing entanglement and compression.

​Close monitoring and inpatient care are also suggested. Sarah was in the hospital for 56 days before she gave birth via C-section, which is how all mono mono twins are delivered for fear of entanglement or compression. (Via WEWS)

The Thistlethwaite's twin girls will soon join their older brother at home.