A mother has beaten very slim odds to give birth to a second set of identical twins.
Casey Saunders' baby girls were monoamniotic monochrionic - or MoMo for short - meaning they shared both a placenta and an amniotic sac.
As well as being rare - with less than one per cent of twins being MoMo - the pregnancy was super high risk.
Complications such as one fetus growing more than the other or the placenta getting twisted, tangled or compressed, meant that Casey would need close monitoring.
She spent the last 60 days of her pregnancy in the Children's Hospital in Colorado, and away from her nine-year-old twin boys Hayden and Cameron, waiting for the girl twins safe arrival.
At her last ultrasound, the day before she would give birth her doctor explained: "Across the wold, identical twins, one in 250 is the rate regardless of where you live in the world.
"Of the one in 250, less than one per cent of those are mono-mono twins, so it's a very small number."
On December 1, at 32 weeks into her pregnancy, Casey gave birth to Maya and Laia, and now four months later they are all back home as one big family.
Speaking to 9 News Casey, an optometric technician, said: "We went from 'Oh my God we're having twins' to 'Oh my God, we're having a really high-risk pregnancy.
"It's hard being in the hospital when you're completely healthy and away from your family, but what kept me going is knowing that each day, every week we're in here, we get to bring home healthy, happy baby girls and the boys can't wait for the opportunity to have sisters."
She added that the older siblings are happy to help with their new sisters.
She told the Daily Mail: "They are doing excellent. Exceeding all expectation. And the boys absolutely adore them.
"They still won't change diapers but they love to hold them and feed them. It's heartwarming to see."
