Eight days after their delivery, two of the newborns are receiving help with breathing and one has undergone surgery for an intestinal problem, said the medical experts at the prestigious Charite hospital.
Teacher Annegret Raunigk, who already had 13 children, gave birth to the quadruplets by caesarian section in the 26th week of pregnancy, after travelling to Ukraine for fertility treatment.
Speaking at a press conference, Christoph Buehrer, head of neonatal services at the Charite university hospital, said the babies were born before fully maturing in the womb, making them "absolute high risk" cases.
The clinic's head of obstetrics, Wolfgang Heinrich, told the press conference that, to his knowledge, Raunigk was the oldest woman in the world to have given birth to quadruplets.
News of Raunigk's multiple pregnancy emerged in April when she dismissed critics who said she was acting irresponsibly due to her age.