BioEd Online

Her name means "white as milk", but when she was born she weighed no more than a tub of butter. Rumaisa, the world's smallest surviving baby, has been unveiled to the world three months after her birth at Loyola University Medical Center in Maywood, Illinois.

With a birth weight of just over 240 grams, Rumaisa now holds the record for the smallest premature baby to be successfully kept alive. She and her twin sister Hiba, also tiny at just under 570 grams, were born by Caesarian section on 19 September.

Doctors ordered the early delivery because the babies' mother Mahajabeen Shaik, originally from Hyderabad and now living in Chicago, was suffering from pre-eclampsia, a condition characterized by high blood pressure. Without intervention, both the mother and babies' health would have been in danger.

The twins' good health is remarkable considering that were born after just 25 weeks and 6 days in the womb, instead of the usual 38 weeks, says Jonathan Muraskas, who helped at the birth. "Both babies came out pink with their eyes open, looking straight at us," he told news@nature.com.

Limits of life

Twenty-five weeks is pretty close to the limit at which a baby can be born and still have a chance of making it, Muraskas says. "The public tends to be fascinated with birth weight, but it's how long they're in the oven that's important," he says.

Staff at the Loyola University centre treated Shaik with steroids to accelerate the babies' development and give them the best chance of survival. "We got mom to 26 weeks and then it was a question of getting them out of there," Muraskas recalls.

Most babies born later than 25 weeks can be saved by careful resuscitation and ventilation. For those who have to be delivered earlier, the decision on whether to try and save them depends on the baby's condition, Muraskas says: "We don't have a crystal ball, but we never let the baby suffer and we never prolong death."

Before about 23 weeks the baby's airways are so underdeveloped that it is almost impossible to get them to breathe even with a ventilator, says Pam Miller, a clinical teacher at Birmingham Women's Hospital, UK. In this situation, she says, "99% of babies won't survive given our current technology."

Start in life

But for those babies, like Rumaisa and Hiba, who stand a good chance, all of the effort and expense is worthwhile, Miller says. "It's phenomenally expensive - hundreds of thousands of dollars - but if the baby survives in good condition they have 70 years of healthy life ahead of them."

That's the future that tiny Rumaisa can now look forward to. Although not completely in the clear yet - Muraskas puts the chances of her showing signs of handicap such as cerebral palsy over the coming year or so at about 5% - ultrasound scans seem to show that her brain is perfectly healthy.

The success adds to Loyola University's impressive track record in rescuing tiny babies. The former record-holder, born weighing just 280 grams but now a healthy high-school student, was also delivered at the centre (see ' Tiniest baby thrives as teenager').

Perhaps it's no coincidence that Rumaisa is also a girl, Muraskas reflects. "She had a few things in her favour, one of which was that she's a girl," he says. Success rates for premature boys remain bafflingly poor in comparison.