Doctors at a clinic in eastern Germany have described the birth of four identical girls as a miracle. Laura, Sophie, Jasmin and Kim were 10 weeks premature but doctors at University Clinic Leipzig say they have good chances of surviving. They were conceived naturally and were delivered by Caesarean section.

Each of the girls weighed about 1,000 grams at delivery on January 6 and will remain at the premature baby unit until they have reached their scheduled date of birth. Obstetrician Professor Holger Stephan says the 31-year-old mother is in excellent health.

Identical quadruplets are very rare. Stephan says the chances of giving birth to identical quadruplets is one in 13 million. "It's very unlikely that quadruplets are naturally conceived and then go on to develop into healthy babies." Identical quadruplets are formed when a fertilised egg divides into four shortly after conception. The embryos develop in separate amniotic sacks and share the same placenta.

Doctor Walter Klockenbusch from the University Clinic in Munster in northern Germany agrees that identical quadruplets are extremely rare: "Nature does not usually allow for births like that." Klockenbusch encountered quadruplet births two or three times during his 20 years at the clinic but none of them were identical.

There are no records of identical quadruplets to be found in Germany's ABC Club, an organisation for families with multiple-birth children of triplets and upwards. "It's possible that it's the first of its kind in Germany," says Hartmut Hartleb, the club's president.

"It's a miracle that the multiple-pregnancy managed to last until the 28th week without encountering any problems," says Stephan. The last quadruplets to be born at the clinic in Leipzig were in 1976. The mother of the latest four babies gained 10 kilograms in weight during her pregnancy and was perfectly healthy until too much amniotic fluid was detected and the size of her belly began to be a cause of concern.

"The mother lives close to the clinic and she was admitted a few hours before the children were delivered," says Stephan. Doctors at the clinic decided to perform a Caesarean section. The first child, Laura, was born at 9:45 pm and the last just five minutes later. The parents say their identical children are "sensational," according to Stephan. The mother is a hairdresser and the father recently bought a large car and finished decorating the girls' room.

The mayor of Leipzig has decided to sponsor the children. "I'm very happy that all are in good health and I wish the family all the best," says Burkhard Jung, who is himself father to four children. Jung plans to visit the family to present them with 500 euros (694 dollars) and offer them help from Leipzig's authorities should they wish it. University Clinic Leipzig has offered to pay for nappies for the next few years.

The new-born girls are the younger siblings to a five-year-old brother. He will have trouble telling his sisters apart, just like their obstetrician does. "They are absolutely identical," says Stephan. Laura is the eldest and Kim the youngest but she is the strongest of the four and weighed in at 1,100 grams. The second to be born, Sophie, weighed just under 1,000 grams at delivery. "It's amazing how well they survived the birth," says Stephan.

Aside from the expected difficulties that most premature babies have, the four girls are in good condition and almost all of their organs are working normally. "Their lungs do need a little assistance, however." Three of the girls can breathe on their own with occasional help while the fourth girl needs ventilator support.

Stephan has been the mother's obstetrician from the start and he says he plans to keep in contact with the family: "Something like this only happens once in your career."