The question lingered in Laura’s mind as she watched her colicky baby, J.D., cry for weeks on end: Did his tummy troubles have anything to do with his cesarean section delivery?
Laura, who asked her last name not be used, had heard from friends that babies benefit from bacteria they receive during vaginal birth that come from their mothers’ birth canal and other body fluids. She had also heard babies born via C-section sometimes develop health issues as a result of missing out on these bacteria.
As J.D. got older and still didn’t feel better, Laura decided to give her son probiotics — a controversial idea whose time may be coming, according to new research. Within a few days, J.D. seemed better, Laura says, and she became another parent in the growing ranks of converts to infant probiotics. “It was a lot of relief.”
Probiotics didn’t end J.D.’s tummy troubles entirely — whenever Laura had to put him on antibiotics, or supplement his diet with formula, the symptoms would reemerge. However, the drugs did seem to help, she says.
“I was so thankful to have something that was a simple solution,” she says. “I don’t need a prescription. I don’t need to go to the doctor for it. It’s readily available to me.”
Like J.D., one in three babies in the U.S. is delivered via C-section. This intervention can be life-saving for both moms and babies, but studies suggest that children delivered via C-section may be more likely to develop obesity, allergies, type I diabetes and inflammatory bowel disease later in life.
More parents are becoming aware of the role of the gut microbiome in their children’s health, says Jenifer Lightdale, a pediatric gastroenterologist at UMass Memorial Medical Center. So some C-section parents, like Laura, are turning to probiotics in the hopes of improving their babies’ health — and they may be on the right track, according to a recent Finnish study published in the journal Microbiome. Still, many pediatricians have their doubts.
Thirteen years ago, a cohort of about 1,200 Finnish moms brought their babies into the world, some vaginally, some via C-section. Researchers at the University of Helsinki gave half of these new mothers special infant probiotics and half a placebo. The scientists have been studying the health of these babies — now preteens — since. So far, the researchers say, results look promising for C-section babies.
They found the C-section babies who didn’t receive probiotics had much lower proportions of beneficial bacteria than vaginally born babies. Probiotics corrected this difference, but only in babies who were also breastfed. This caveat may have to do with the fact that breast milk contains important food for bacteria, called prebiotics, while most formula does not.
Not all microbes in probiotics are equally beneficial, explains Tommi Vatanen, a microbiologist at the University of Auckland in New Zealand who was not involved in the study. Every type of microbe performs a different function and interacts with the body differently.
Some strains of bacteria found in the infant gut are “immunomodulatory” — that means they interact directly with the immune system. These bacteria are particularly important during infancy, when “the long-term programming of the immune system happens,” says Katri Korpela, an immunobiologist at University of Helsinki and the study’s lead author. During this time, “the immune system is constantly talking with the microbes in the gut.”
Missing out on this immune education could be what leads to later health problems. According to an earlier study also based on Korpela’s group of babies, those born via C-section were almost 70 percent less likely to develop a food allergy before the age of five, and almost 60 percent less likely to develop eczema if they had received a probiotic compared to other C-section babies. This difference wasn’t seen in the vaginally born babies, which suggested to researchers that allergy risk has something to do with the effects of C-section.
Given these results, should parents of C-section babies rush to buy probiotics? Korpela says the potential benefits clearly outweigh the risks. But Adam Ratner, a pediatric gastroenterologist at New York University Langone Health, isn’t so sure.
“It’s not like anything bad is going to happen… Except when it does, right?” Ratner says.
In October of 2014, for example, an eight-day old baby delivered via C-section at Yale New Haven Hospital, died in intensive care after being given several doses of probiotics contaminated with mold.
Probiotics aren’t regulated by the U.S. Food and Drug Administration, Ratner and other doctors point out. Lack of regulation makes it more likely that pathogens and fungus could be inadvertently introduced to probiotics during the production process, as was the case at Yale New Haven.
It’s important to recognize that in this incident, the baby was premature and immunocompromised, says Josef Neu, a neonatologist at University of Florida Health. Probiotics are most likely harmless in healthy babies brought to full term, he adds.
The more likely problem is that probiotics purchased by consumers don’t contain the live, beneficial bacteria the label advertises. The mothers involved in Korpela’s study benefited from rigorously controlled probiotic strains. That’s not what consumers get when they pick up an infant probiotic at their local grocery store, says NYU’s Ratner.
Lack of regulation isn’t the only issue with infant probiotics. No one really has a complete understanding of what the ideal infant probiotic should contain, says Stacy Kahn, a pediatric gastroenterologist at Boston Children’s Hospital. Although evidence points to the importance of immunomodulatory bacteria, there are many more strains of bacteria whose functions are a complete mystery to us.
“I don’t know that we have a well-defined community that we know will be universally beneficial and without risk,” Kahn says. “We don’t know what strains, we don’t know for how long.”
This lack of knowledge is all the more of a reason to continue studying probiotics, she says, following children like those in Korpela’s cohort as they continue to grow.
But Korpela doesn’t plan to spend a lifetime waiting around for data. Her baby daughter is just five weeks old and already getting probiotics. “It’s a very easy thing for me to do, I think,” Korpela explains during our interview as her daughter coos and trills like a dove in the background. “I mean, I think I might not if I didn’t see such clear beneficial results.”