Why It’s So Hard to Know What to Do With Your Baby

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When you go to a website with a question pertaining to the care and maintenance of your newborn baby, you will almost certainly see this disclaimer attached to the advice: “Ask your pediatrician.”

The problem is that, in many cases, the answer depends on the pediatrician you ask. In the few short months that my son has been alive, various doctors and specialists have said that my baby is allergic to soy or that he probably isn’t; that I should place him, screaming, onto his stomach for 30 minutes a day to help strengthen his back muscles or that I shouldn’t bother; that he should take probiotics or that he shouldn’t; that I should use a steroid cream on his face or that I shouldn’t; that he should get the tissue under his tongue snipped—or “released”—to help him breastfeed more easily or that he shouldn’t (and within the pro-release “community,” some have said that the procedure should be done only with surgical scissors; others have said that it should be done only with a laser).

The reason for all this disagreement comes down to the fact that there simply isn’t good evidence—as in large, randomized, controlled, blinded trials—for many pediatric practices. No scientist has conducted a gold-standard study that would tell parents exactly which probiotic or steroid cream leads to the best possible outcome. (Not to mention that people disagree on what the best outcome even is.) As maddening as these conflicting instructions might be for new parents, they should also be reassuring: They suggest that there’s often no wrong or right way to take care of your baby.

[ Read: The worst pediatric-care crisis in decades ]

Many pediatricians don’t even agree with their own professional organization. The American Academy of Pediatrics says you should start giving your breastfed baby iron supplements at four months and continue until they start eating solid foods, but when I asked my baby’s doctor about this, she said that we should start the iron supplement after he starts solids. And a mom friend told me that her baby’s doctor said she shouldn’t administer iron at all. The AAP tells parents not to elevate the head of their baby’s bassinet to help with reflux, which must have been news to my baby’s doctor—she recommended that we do so—and to the maker of our bassinet, which sells low-incline risers for this express purpose. The AAP also says that babies should sleep in the parents’ room for the first six months , but two different providers told my husband and me that we should feel free to evict our son after a month or two.

One day, I asked a pediatric allergist if my baby’s eczema might be a sign that he’s allergic to dairy.

“Look, I don’t know!” he said in exasperation. “Stop Googling and read Emily Oster.”

As it happens, I do read Emily Oster, the author of the newsletter ParentData and several popular books about child-rearing. And I called her to ask why it’s so hard to know what, exactly, to do with your baby.

She told me that conducting a randomized, controlled trial on, say, the amount of tummy time an infant needs would require millions of dollars in funding and thousands of parents laying their children on their stomach for differing lengths of time for months. Few parents would do that. And when the scientists did finally arrive at the result—say, 30 minutes a day—they’d have little to show for it. “I can’t patent 30 minutes,” Oster told me. There’s no blockbuster tummy-time drug they could cash in on.

Instead, doctors rely on what they were taught in medical school or residency, or even “what they were taught by their moms or dads or grandparents,” says Aaron Carroll, a pediatrician and the CEO of AcademyHealth, a membership organization of health-services researchers. Medical-school curricula are, in part, evidence-based, but some of the material is more like “professional wisdom,” or practices that are rooted in tradition, Carroll told me.

Take tongue-tie releases, already-controversial procedures that are made only more controversial by the fact that most ear, nose, and throat doctors perform them with scissors, whereas most pediatric dentists perform them with a special laser. The reason? That’s just how they’ve always done it. “People tend to be very wedded to what they do, and there is no good evidence that shows that one is better than another,” says Anna Messner, a pediatric ENT at Texas Children’s Hospital who co-authored a position paper on tongue-ties.

[ Read: Pediatricians see an alarming number of noodle-soup burns ]

Other fields of medicine have patchy evidence bases too, but pediatrics is unique because people have so many questions about every little thing , and the answers all feel very high-stakes. Few adults worry that taking the wrong multivitamin will ruin their life, but giving your baby the wrong kind of formula can feel like a matter of life and death—at least when you’re hormonal and running on two hours of sleep.

Carroll told me about the day, 22 years ago, when he brought his eldest child home. The hospital had placed a hat on his baby’s head, and Carroll hadn’t been sure if he was allowed to take it off.

Carroll, a pediatric fellow at the time, had asked a more experienced pediatrician at his clinic how long babies are supposed to wear the hat.

“And he just laughed,” Carroll told me. “Because no one knows.”

This dearth of evidence also allows for the flourishing of woo-woo, unproved baby interventions, such as baby chiropractors . Desperate parents will take their babies to a chiropractor for the inexplicable crying jags known as colic, the baby will eventually get better (because all colic eventually gets better), and suddenly the chiropractor can promote “evidence” that their spinal manipulations work for colic.

Of course, some pediatric advice—about, say, the importance of childhood vaccines and placing babies on their back to sleep— is grounded in firm evidence. The problem is that many pediatricians don’t differentiate between advice that’s based in science and advice that’s just probably a good idea.

To figure out which is which, Oster recommends asking your pediatrician, “Why are you recommending that?” This is not to challenge their expertise, but to determine whether the doctor is relying on a study, a hunch, or something else.

And for parents, clashing pediatric advice can, paradoxically, be a relief. When doctors all agree on something, such as vaccines, it’s often because the consequences are important and well studied. But “in the places where people disagree, the effects are small,” Oster said. When large meta-analyses point in opposite directions, or when different specialists come to different conclusions, or when baby books offer conflicting suggestions, it’s often because what you do won’t matter all that much.

“That means I don’t have to rack my brain over these probiotics and which one is really the best one?” I asked Oster.

“Oh my God, you’re thinking about which probiotic?” Oster said. “No, that’s bananas.”