WARSAW, Poland (AP) — A hospital in southern Poland says sextuplets have been born through cesarean section and all are said to be doing well.

Maria Wlodkowska, a spokeswoman for the University Hospital in Krakow, said the four girls and two boys were born Monday in the pregnancy's 29th week and that each weighed about 1 kilogram (2.2 pounds.)

She said the babies are fine but have been placed in incubators to assist their development.

Wlodkowska said that according to existing documentation, it is the first such birth in Poland.

Only one in nearly 5 billion pregnancies leads to sextuplets.