Last month, a baby girl widely considered the most premature European baby ever to survive left a German hospital and headed home. Frieda Mangold was born more than four months early, at 21 weeks and five days. She weighed a smidge over a pound.
Her twin, Kilian, succumbed at six weeks to heart and intestinal complications, but Frieda slowly soldiered on. Her doctor at the Fulda Children’s Clinic, Reinald Repp, said there was “no indication that she will not be healthy,” according to the Daily Mail, and described her survival as a “medical miracle.”
Yet what exactly constitutes a medical miracle is unclear. Any premature baby is at risk for complications — the tiniest of the tiny even more so. News of Frieda’s birth and her tenaciousness after five months of neonatal intensive care has raised an issue that is discussed in medical circles out of clinical necessity, yet rarely reaches beyond hospital confines: how young is too young to save?
(More on TIME.com: Why Delaying Delivery by Just Two Weeks Boosts Baby’s Survival)
Doctors in the U.S. often advise that premature babies born before 23 weeks be given only “comfort care” — swaddled, they’re handed to their parents to hold, free of medical interventions. If parents insist on treatment and the baby weighs more than 500 grams (about 17.5 ounces), “most of us give it a try,” says Gerri Baer, a neonatologist in Rockville, Md., who also happens to be my oldest friend.
Typically, 23 weeks is considered the limit of viability, although there have been some 22-week survivors. Because even early ultrasounds that predict a due date are essentially guesstimates — with a plus/minus range of about five days — it’s tough to definitively date a preterm birth. A full-term pregnancy lasts 40 weeks.
Every week — every day — that a baby stays in the womb affords a better shot at survival because the infant’s development is more complete, a phenomenon that Alan Fleischman, medical director at the March of Dimes, calls a “biological continuum.” This holds true even when babies are not technically premature: a study published in the June issue of Obstetrics & Gynecology shows that infant mortality rates double when babies are delivered at 37 weeks rather than waiting until at least 39 weeks. Potential complications of even relatively late — but still early — births have prompted the American College of Obstetricians and Gynecologists to advise against elective deliveries before 39 weeks.
Babies born around 37 weeks can have breathing problems and require ventilation. But the extremely serious complications occur at much younger gestations: infants born before 26 weeks are at greatest risk for significant disabilities — cerebral palsy, perhaps, or deafness or mental retardation.
(More on TIME.com: A Blood Test to Predict Premature Birth Could Hit the Market Next Year)
In most cases, doctors have a bit of time between the parents arriving at the hospital and the actual delivery to discuss outcomes and prepare. “We sit down and talk with them,” says Baer.
Between weeks 23 and 24, most neonatologists leave the decision about whether to resuscitate in the parents’ hands, and nearly all parents ask doctors to resuscitate. If the baby is so tiny that a breathing tube can’t inserted, however, all bets are off.
For babies born after 24 weeks, doctors generally believe that the benefits of resuscitation outweigh the downsides. “Between weeks 22.5 and 24 is the gray zone,” says Baer, noting that just one in 10 babies born before 24 weeks survives. “Above 24 weeks, every baby gets a try.”
Caring for such fragile babies is a tough, heartbreaking job, and there’s much that’s unknown. Girls, for example, have better outcomes than boys; black girls have the best chance at survival, white boys the worst. Why? “We don’t know,” says Baer.
(More on TIME.com: Study: Preterm Birth Raises the Risk of Childhood ADHD)
Birth weight counts for a lot as well: every additional 100 grams (3.5 ounces), as well as lung-developing steroids administered before delivery, give a baby a notch up on a widely used outcome scale maintained by the National Institute of Child Health and Human Development that can predict how a premature baby may fare. Plugging in the stats for baby Frieda is not an exercise in optimism: even assuming the use of steroids, there is just a 3% chance of survival without “profound neurodevelopmental impairments.”
Still, when it’s your baby, it’s probably human nature to believe you’ll beat the odds. Baer sees that reflected in her conversations with parents-to-be.
“I can tell them what the stats are, but most people are going to believe their kid is going to be okay,” she says. “If you’re in that heightened emotional state, the data is not all that important to you.”
