Longer skin contact leads to better neurological development

Skin-to-skin cuddling with a parent has lasting cognitive benefits for premature babies, according to a new study from Stanford Medicine. Premature babies who had more skin-to-skin contact (also called kangaroo care) during their hospital stay were less developmentally delayed at one year of age, the study found.

The study, which will be published online on July 11, 2024, Journal of Pediatricsshowed that even a small increase in skin-to-skin time made a measurable difference in babies’ neurological development during their first year of life.

It’s interesting and exciting that it doesn’t take much to really improve babies’ development.”

Katherine Travis, PhD, lead study author and assistant professor, Weill Cornell Medical School and Burke Neurological Institute

The study’s lead author is Molly Lazarus, clinical research coordinator in pediatrics, formerly at Stanford Medicine and now at Weill Cornell Medical School.

The procedure is simple: A parent holds the baby, who is wearing only a diaper, on their chest, right next to the skin. But because premature babies in the hospital are small and fragile and often connected to many tubes and wires, holding the baby can seem complicated. Parents may need help from their baby’s medical team to get everything ready. That work is worth it, the study showed.

“It didn’t matter if the baby came from a high-income or low-income family. The effects we saw were the same. And it didn’t matter if the baby was sicker or less sick – both responded to the treatment,” Travis said.

Neurological complications are a challenge

Over the past 50 years, survival rates for premature babies have improved dramatically thanks to better treatments for many of the complications of preterm birth, defined as birth three weeks or more early. For example, neonatologists have developed effective methods to help premature babies in the neonatal intensive care unit (NICU) breathe easier, even when their lungs are not yet fully developed.

But babies born prematurely are also at risk for long-term neurodevelopmental problems, including developmental delays and learning disabilities. Doctors and families have long hoped for treatments they could use during the newborn period to prevent such problems.

“Ultimately, we want our patients to be healthy children who can achieve the same milestones as if they didn’t come to the NICU,” said study co-author Dr. Melissa Scala, clinical professor of pediatrics. Scala is a neonatologist who cares for premature babies at Lucile Packard Children’s Hospital Stanford.

“Our findings justify skin-to-skin care as an important intervention in the neonatal intensive care unit to support our goal of discharging the infant from the hospital ready to learn and develop,” Scala said.

Skin-to-skin care was first used in low-income countries to increase the survival rate of babies, where it is often used on healthy infants born after a full-term pregnancy. In rural or impoverished areas, it is an important method of keeping newborns warm, strengthening the bond between parent and child, and facilitating the initiation of breastfeeding.

The practice has been slower to gain acceptance in the United States, particularly for premature babies, who typically receive state-of-the-art intensive care. But a growing body of research suggests that the practice has a positive effect on premature babies’ brains, possibly because it can give them the same developmental stimulus they would have received without being born prematurely.

More skin contact was better

The research team reviewed medical records of infants born very preterm, at least eight weeks early, who were cared for at Lucile Packard Children’s Hospital Stanford between May 1, 2018, and June 15, 2022. Shortly before the study began, nurses in the hospital’s neonatal intensive care unit had begun making notes in patients’ medical records about developmental care practices, including the amount of time parents held their babies skin-to-skin.

The study involved 181 premature babies who had no genetic or congenital conditions that could affect neurological development and who had received follow-up assessments after leaving the NICU. All very premature babies are eligible for care through California’s High Risk Infant Follow-Up Program until age 3. The program provides developmental testing and connects families with appropriate therapists if their children have developmental delays.

The study used records from follow-up visits the babies received at 6 and 12 months of age, meaning their ages were adjusted to account for how early they were born.

The assessment included measures of visual-motor problem solving on standard tasks (such as dropping a cube into a cup) as well as expressive and receptive language skills (such as turning to hear where the sound of a bell is coming from).

In addition to taking into account the gestational age of the infants (how early they were born), the results were adjusted for the socioeconomic status of the families and for four common complications of preterm birth: bronchopulmonary dysplasia, a respiratory complication, brain hemorrhage or bleeding, sepsis, a bloodstream infection, and necrotizing enterocolitis, an intestinal disease.

The babies studied were born on average in the 28th week of pregnancy, i.e. about 12 weeks before the expected due date. They stayed in the hospital for an average of about two and a half months.

Babies in the study spent an average of about 17 minutes of skin-to-skin care per day, usually in sessions lasting more than an hour but occurring less than two days per week. Seven percent of families did not care for their skin, and 8 percent cared for more than 50 minutes per day.

Small increases in skin-to-skin care were associated with large differences in 12-month neurodevelopmental scores. On average, 20 minutes more skin-to-skin care per day was associated with a 10-point increase on the Neurodevelopmental Rating Scale. Similar to an IQ test, the scale has an average of 100 points; a score of 70 or less indicates significant developmental delays.

The frequency and duration of skin-to-skin contact could be predicted by cognitive scores at 12 months, even after accounting for potential confounding factors, including infant gestational age and medical complications, family socioeconomic status, and frequency of neonatal intensive care unit visits.

How does it work?

Although the study was not designed to examine the positive effects of skin-to-skin care on babies’ brains, the researchers have some educated guesses.

“We look at the womb as a benchmark for premature babies. In the uterus, the fetus is physically protected, hears the mother’s heartbeat, hears the mother’s voice and probably hears her digesting her sandwich,” Scala said. “In the NICU, they’re not surrounded by anyone and hear the fan in the incubator; it’s a very different environment. Skin-to-skin care is probably the closest thing to mimicking the womb.”

Parents can also benefit from skin-to-skin care, which in turn can benefit their newborns, according to the research team.

“The NICU environment is very stressful for parents and babies, and skin-to-skin contact can mitigate that,” Travis said, noting that it is not uncommon for parents with a very young, sick baby to develop post-traumatic stress disorder.

In addition, many premature babies are not developmentally ready to breastfeed, and skin-to-skin contact can be an alternative way to strengthen the bond between parent and baby.

The researchers hope their findings will motivate medical teams to support and encourage parents in neonatal intensive care units across the country to practice skin-to-skin care by showing them the long-term benefits of this simple but important technique.

Packard Children’s recently expanded its infant development program by adding neurological nurses, additional physical and occupational therapists, a psychologist, and child life and music therapy specialists to the NICU and intermediate care units. The expanded team can create individualized developmental care plans for high-risk infants.

Scala hopes that other hospitals will follow his example.

“I would like people to see this as part of the medical plan, not just as something nice we do, but as something we really do intentionally,” Scala said. “Our findings underscore the value of having parents in the NICU providing this important part of infant care.”