Mom Births Rare 'Mono Mono Twins'

Sarah Thistlethwaite was once told she wouldn't have children; just in time for Mother's Day, the Ohio woman delivered twin girls in a rare kind of pregnancy that happens about once in 10,000 births, or in, at most, 5% of all twins. As News Net 5 reports, the girls were mono mono twins—or twins that occur when an embryo splits more than eight days after fertilization, and which share the same amniotic sac and placenta. WCPO notes Thistlethwaite and her husband didn't learn they were expecting twins until her 19th week of pregnancy—and her third ultrasound. It's a high-risk pregnancy, and Thistlethwaite was hospitalized for 58 days before her C-section at 33 weeks on Friday.

Not enough cute factor? Jenna and Jillian Thistlethwaite were born holding hands. And lightning strikes twice: Akron Children's Hospital, where the Thistlethwaite twins were born, will see the birth of another set of mono mono twins this week. Amanda Arnold is also pregnant with twin girls. "I've been practicing high-risk obstetrics for about 35 years and I've seen less than 10 cases," says a doctor. (Another less-than-common pregnancy case: The mother of a 25-year-old gives birth to triplets.)