Quadruplets are only born once in every half million pregnancies, so when Christina Tetrick found out her quadruplets were actually two sets of identical twins — she was glad to be lying down.
"I said, well 'what are you seeing that you're so quiet?'" Tetrick remembers asking the doctor during her ultrasound. "And she said, 'honey, you have four babies in your belly.' And it was a good thing I was laying down — that was just a shock!"
Twins are common on both sides of Tetrick's family — but two sets of identical twins are uncommon in any family.
"The fact that she has quads is rare enough," said Dr. Scott Robert, a specialist in maternal fetal medicine. "That one set would be identical is rare. That both sets would be identical, I just don't really have any idea."
Rare, but Natural
Tetrick, 28, who did not take fertility drugs, is 22 weeks into her first pregnancy. Her doctors say they believe she is pregnant with two sets of twins — all boys.
Tetrick's doctors say they can't find any statistics on other mothers who've been pregnant with two sets of identical twins.
In Tetrick's case, doctors say it took a very rare chain of events. Two different eggs from Tetrick were fertilized — resulting in fraternal twins. Then those two separate eggs both split — resulting in two sets of identical twins.
These twins are called identical because, of course, they will have the same identical genes. Fraternal twins will look similar, but like brothers.
Nature and the Army Calls
Though Tetrick and husband Pat, married for less than one year, are thrilled about a future with their new family — Christina Tetrick will have to get through the pregnancy without her husband. The Army Reserve has assigned Pat Tetrick to a one-year tour.
"One of the things Pat said as soon as I got pregnant is that he wanted to go to every doctor's appointment, he would not miss one," she said. "So that's hard."
Tetrick is due in early May, though doctors expect her to deliver sooner. In the meantime, she is sending her husband ultrasound pictures of their rare family.