A woman has given birth to naturally conceived identical quadruplet, all sharing one placenta and developing from a single fertilized eggA woman has given birth to naturally conceived identical quadruplet, all sharing one placenta and developing from a single fertilized eggA woman has given birth to naturally conceived identical quadruplet, all sharing one placenta and developing from a single fertilized eggA woman has given birth to naturally conceived identical quadruplet, all sharing one placenta and developing from a single fertilized eggA woman in Australia has given birth to a rare set of identical quadruplet daughters after a pregnancy her doctor described as "unheard of." All four babies are identical quadruplets, meaning they shared a single placenta, the hospital said. A woman gave birth to a identical quadruplet girls at Royal Brisbane and Women's Hospital in Queensland, Australia. "Monozygotic [or identical] quadruplets are estimated at 1 in every 15 million pregnancies, but to share the same placenta, this is unheard of." Na'amoana and her husband were already the parents of four children ages 1 to 10, so the quadruplets' birth instantly doubled their number of children.