That Plastic Bag You're Carrying Could Save a Newborn's Life. Here's How


(A version of this article originally appeared at SciDevNet, a site that "brings science and development together through news and analysis." It's worth checking out.)  

An everyday plastic bag, like the type you probably use to carry groceries, could help save the lives of some of the world’s most vulnerable newborns, according to a recent study in the Journal of Pediatrics.

Polyethelene bags are often used in developed countries to keep extremely premature newborns warm immediately after birth, but only for the few minutes before they can be placed in an incubator.

The study, conducted in 2011 at University Teaching Hospital in Lusaka, Zambia, tested whether this approach would work for longer durations with moderately pre-term infants (between 26 and 36 weeks’ gestational age) in resource-constrained settings.

Here’s how it worked: Preterm infants were randomized at birth, with some placed in a polyethylene bag immediately after birth and others receiving normal thermoregulation techniques. Researchers checked the temperatures of the newborns an hour later.

The results were stunning. Infants in plastic bags were 79% more likely to be an appropriate temperature than the control group — 59% and 33% respectively, an absolute difference of 26%.

Hypothermia, or having a low body temperature, is associated with increased morbidity and mortality in newborns. It’s a major risk for babies born in developing countries. While estimates vary significantly, some studies show rates in newborns as high as 83%

Hospitals in developing countries have few incubators or radiant warmers, which are expensive to procure and difficult to maintain. If a hospital does have one of these devices, there’s a decent chance it’ll be broken and inoperable.

But many women don’t deliver at the hospital, anyway. Sometimes, they prefer to give birth at home, but too often, they’re victims of geography and circumstance: A health facility may not be near enough to home, and if it is, it’s often not qualified to provide emergency obstetric and newborn care.

In an interview, Dr. Walderama Carlo, an author of the study, said that “all babies are predisposed to hypothermia,” in part because they “have a large surface area to body mass.” Basically, it’s easy for heat to escape. Once it does, infants have a difficult time producing more: They can’t immediately shiver. Their second line of defense is brown adipose tissue, or “brown fat,” which also generates heat.

But premature newborns don’t have enough of it, so they’re even more predisposed to hypothermia, according to Dr. Carlo. Without these heat-generating mechanisms, infants cannot recoup the heat lost through evaporation, convection, conduction, and radiation. Once they’re cold, they need outside warmth — either from the mother or an external device — to stay at the right temperature. The researchers believe that the plastic bag prevents evaporative cooling, keeping the baby warm longer.

In addition to reducing hypothermia, plastic bags can also help facilitate Kangaroo Mother Care, a World Health Organization-recommended method to care for preterm infants.

As Dr. Carlo explained to me, a main issue with KMC in sub-Saharan Africa is that “many mothers don't do skin-to-skin because the babies void on them, or have a stool on the mother.”

In other words, no mother wants to get pooped on.

“And we think that plastic bags, in some ways, may serve as a diaper in places where they don't have diapers,” he continued.  

Dr. Lisa Umphrey, a pediatrician with Medicine Sans Frontiers who has practiced in Uganda for five years, said that the study “suggests that the practice has importance in international, under-resourced settings…Given the high rates of neonatal morbidity and mortality in these clinical settings, this is a topic that deserves much more discussion and investigation.”


As a first-line defense against hypothermia, food-grade plastic bags had a significant effect. Still, even babies put in the bags had a 41% chance of being too cold one hour after birth.

Other low-cost solutions, such as the Embrace BabyWrap, may help keep low birth weight babies warm longer. The device (pictured above being used in Mbale, Uganda) is an infant warmer optimized for hospitals with intermittent electricity and small budgets, and happens to be at University Teaching Hospital in Lusaka. Dr. Carlo said that it may be one “long-term solution for some patients.”

Ultimately though, when it comes to cost, “there's nothing as inexpensive as [plastic bags]” for hypothermia, Dr. Carlo said. “These are food-grade bags, [we can] just throw them away.”