July 13, 2001 -- It's hard enough for seven fetuses to survive in the womb. But it doesn't get any easier after birth.
The basic problem is that the more babies a woman delivers, the more likely they'll be born weeks or even months prematurely.
"The more prematurely the baby is born, the harder it is for the baby's nervous system, lungs, heart, kidneys to adapt to the new demands of life outside the woman," explains Peter Gorski, assistant professor of pediatrics at Harvard Medical School.
For babies like the septuplets born in Washington Thursday night, 12 weeks prematurely, the most common problems are also the most life-threatening:
Lack of oxygen. Lungs are usually so underdeveloped that ventilators are required to keep them inflated.
Infection. Since the immune systems are so immature, they have more problems fighting harmful germs.
Bleeding in the brain. Because blood vessels in the brain are not fully developed, they're unable to handle the increased blood flow that's required outside the womb.
Premature babies face their toughest battle in the first few days after birth.
"The first couple of days are really critical in terms of survival," says Peter Shapiro of the American Academy of Pediatrics. "Babies that get through the first 48 hours are much more likely to survive."
But even as they grow older, children born very prematurely run a greater risk of developing learning problems, including attention deficit disorders and dyslexia.
For many years, the number of children at risk for these problems had been growing as more and more women turned to fertility treatments that increased the odds of multiple births.
However, over the last few years, safety concerns have prompted fertility doctors to try to reduce the numbers by implanting fewer embryos into their female patients. Over the course of infertility treatment, women usually receive several embryos in the hopes that one will make it to delivery.
More women who are pregnant with multiple fetuses are also choosing to undergo mulitfetal pregnancy reduction, a procedure that reduces the number of fetuses carried in order to keep the remaining two or one healthy.
Recent statistics from the Centers for Disease Control and Prevention show that while the number of twins born in the country, at last count 114,000, continues to grow, the number of women giving birth to triplets, or more, is on the decline.