The children, all girls, were delivered by caesarean section at the hospital in the 28th week of pregnancy.
The parents, 34-year-old Jenitar Sau Na'amoana and her husband Jortham, already have four children between the ages of one and ten and had not planned to have more, according to a press release. The fact that the couple were expecting quadruplets naturally came as a complete surprise to them.
So-called monochorionic quadruplets, where all four children come from one egg and share a placenta, are extremely rare. This is associated with a very high risk - partly because the fetuses can start taking blood from each other via blood vessels in the placenta, and partly because one of the fetuses risks not getting enough of the placenta and growing poorly, says Bo Jacobsson, professor of obstetrics and gynecology at the University of Gothenburg.
The mother has therefore been under the care and supervision of a large team of experts at the Royal Brisbane and Women's Hospital since the tenth week of pregnancy. She was admitted in week 25 to be under continuous supervision.
"We have never seen a spontaneous quadruplet pregnancy like this. Jenitar has taken everything in her stride from the very beginning. She has somehow managed to avoid all complications and risks, both for herself and for the children," continues Alexa Bendal, a specialist in obstetrics and gynecology at the Royal Brisbane and Women's Hospital.
Given the risk of complications during pregnancy, Swedish maternity clinics in multiple pregnancies are more interested in whether there is one, two or more placentas, according to Bo Jacobsson.
It is not interesting to us whether the embryos come from the same egg or not because it is not directly related to the risk of complications.
He only knows of one similar case, which was reported in an article published in 2013. It involved quadruplets who shared a placenta and were born in Leipzig, Germany.
Bo Jacobsson does not believe that the case of the identical quadruplets in Brisbane is particularly interesting for researchers, but rather an unusual situation in healthcare.
Monozygotic quadruplets mean that one sperm fertilizes an egg, which then divides into four parts and gives rise to four embryos, quadruplets, which are genetically identical and always have the same sex.
In this case, the egg division occurred later – four to eight days after fertilization, which meant that the identical quadruplets shared a placenta.
If the egg division had occurred during the first three to four days after fertilization, the embryos would each have received their own placenta.
