Their mother Sarah had spent 57 days on bed rest to minimize the risks and was relieved to give birth to two healthy girls.
The twins were born 45 seconds apart and as soon as the doctors held them close to each other, they clasped hands, stunning everyone in the delivery room.
Two years later, the bond between the sisters has grown stronger than ever, their mother told People magazine.
'Sometimes if my husband goes to the store, he'll take one twin and I'll keep the other,' Thistlethwaite said.
'When that happens, they both get really upset and ask for each other. They're definitely really close. They're like two peas in a pod.'