Just in time for this year's Mother's Day celebration, a middle school teacher from Ohio had what would probably be one of her best mother's day gift ever, a pair of identical twin girls.

What made the girls extra special is that they were so called monoamniotic-monochorionic or mono mono twins, identical twins that shared one amniotic sac while they were in their mother's womb. Mono mono twins develop when the embryo splits after the amniotic sac has been formed, which typically occurs about nine days after fertilization.

Mono mono twins are extremely rare occurring only in one in 10,000 births. The reason is that these twins share the same amniotic sac and this increases their likelihood of getting entangled in each other's cords. It is also possible that one of the twins compresses the other twin's cord which could obstruct the flow of blood and nutrients and cause fetal death. The other twin may also receive most of the nourishment which could lead to the other twin getting malnourished.

"Sarah was given the option to deliver between 32 and 34 weeks gestation. This type of twin is at high risk for stillbirth because of cord entanglement," said Melissa Mancuso, a perinatologist at the Akron Children's Hospital. "We were just having a discussion about how difficult a decision it is to make, weighing the risk of prematurity vs. the risks of entanglement."

Against all odds, the twins Jenna and Jillian were born via C-section at the Akron General Medical Center on Friday at 2:41 PM. Jenna, who was older by 48 seconds, weighed 4 pounds and measured 17.2 inches. Jillian, on the other hand, was 3 pounds and 13 ounces and measured 17.5 inches.

Even from birth, the twins appeared to be partners for life. They were holding hands right after their delivery. "They're already best friends," Sarah said. "I can't believe they were holding hands. That's amazing."

Aggressive fetal monitoring can increase the survival odds of mono mono twins from 81 to 95 percent but the chances for survival drop to 50 percent without proper monitoring. Sarah had to be on bed rest for 57 days and had to be attached to fetal monitors for 20 hours per day for almost two months to ensure the safety and survival of the twins.

Because the babies were born at around 33 weeks, they are considered premature and will need to stay at a neonatal intensive care unit at the Akron General Medical Center where they will likely stay for up to four weeks before they will be ready to come home.

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