When a baby is born, parents are often awed and alarmed to find themselves responsible for this tiny new person, and they desperately want to do their very best to keep their infant safe and healthy. New mothers worry about everything from SIDS to vaccines, from feeding practices to sleep hygiene, and they are bombarded with conflicting advice about caring for their babies. Myths and misinformation abound. Finally someone has written a truly science-based guide to the first year of life: The Science of Mom. The author, Alice Callahan, is a research scientist with a PhD in nutritional biology. When her first child was born, she had a lot of questions, and thanks to her background she knew how to look for reliable answers in the scientific literature. She started writing the Science of Mom blog and eventually turned her findings into a book.
Her first chapter covers the important concepts for understanding how to think about scientific studies:
- Good science is a process that takes lots of experiments, time, and people.
- Good science is peer-reviewed.
- One study on its own isn’t worth much, but scientific consensus is trustworthy.
- Some studies are more valuable than others (here she covers the various types of study from animal studies through observational studies in humans to RCTs and meta-analyses).
- Numbers matter (sample sizes).
- Don’t believe everything you read on the Internet (here she gives some practical tips for evaluating whether a website is reliable).
- Correlation is not causation (she uses my favorite example of the correlation between autism diagnoses and the sales of organic food).
- We can’t eliminate risks (but science can quantify the risks and benefits and families can use the information to decide what risks they are personally willing to take).
- Find smart allies (experts and providers you can trust).
- Forget about perfection and pay attention to your baby.
In subsequent chapters she delves into what science has to say about various topics. She finds that there is seldom a simple yes-or-no answer to these questions, and she presents the evidence on both sides fairly, adding a common-sense perspective.
When to cut the umbilical cord
There are clear benefits of delaying cord clamping, but there are also risks. We don’t know how long a delay is optimal. And there are practical problems like the logistics of resuscitating a baby in distress and of banking cord blood.
Vitamin K shots and eye goop
She explains why newborns are given vitamin K injections, illustrating the danger of vitamin K deficiency bleeding (VKDB) with a horror story about a baby who nearly died from a brain bleed after the shot was inadvertently omitted. The evidence shows that oral supplements are not as effective, and that the injections are safe.
Antibiotic eye ointment is routinely used to prevent blindness and other complications of gonorrhea and chlamydia, but the incidence of gonorrhea in the population has declined. If a woman is at very low risk of sexually transmitted diseases, eye prophylaxis might reasonably be omitted; but when European countries tried doing it selectively instead of universally, the number of gonococcal infections in newborns rose. And the risks of treatment are minimal.
Breast is best
For some families, breastfeeding is clearly the best choice, but for others it isn’t. The benefits of breastfeeding have been hyped beyond the actual evidence. It is definitely beneficial; but the advantages are not huge, and formula feeding is a perfectly good option for mothers who can’t breastfeed or prefer not to. There are even some benefits to formula: it is fortified with iron, so bottle-fed babies are less likely to become anemic than breast-fed babies.
There are benefits to keeping your baby close, but sleeping in the same bed is dangerous. She covers the published evidence, cultural differences, SIDS, factors that might have influenced study findings, and how to minimize the risks if you choose to co-sleep.
One of the biggest problems for parents of newborns is chronic sleep deprivation. She covers the research on normal infant sleep patterns, arousability, and how infants learn self-soothing behaviors to fall asleep without help. Sleep training works, but not for all infants. It doesn’t harm babies, and it can help stressed parents get the sleep they need to be good parents.
This chapter starts with an affecting personal story. One of the author’s uncles died at age 6 of encephalitis caused by measles. What had appeared to be a typically benign, uncomplicated case of measles suddenly turned deadly. The benefits of vaccines are undeniable. She shows the statistics for lives saved and she debunks many of the common anti-vaccine myths. She gives a lucid explanation of herd immunity. She recognizes that vaccines are not without risk, but the evidence shows that the risk is very small and the risks of not vaccinating are much greater. She explains how vaccines are rigorously tested and monitored for safety. She tells how the first rotavirus vaccine caused intussusception in a few recipients and how the system responded to create a safer vaccine. The new vaccine has prevented thousands of hospitalizations for rotavirus infection, and has even decreased the incidence of the disease in the unvaccinated through herd immunity.
When to start solid foods
When I started practicing medicine we used to recommend starting rice cereal at 1 month so the solid food in the tummy would help the baby sleep through the night; it didn’t work. The evidence for when to start solid foods is conflicting, and there are confounding factors like varying hygiene practices and resources in different cultures. Starting between 4 and 6 months reduces the risk of anemia in breastfed babies and may reduce the risk of allergies, celiac disease, and type I diabetes. Starting at 6 months may lower the risk of diarrhea and the baby is more developmentally ready, making feeding easier. Waiting longer than 6 months is not advisable.
She says, “Take the focus off the calendar and put it where it belongs, with the little one doing the eating.” Babies develop at different rates and have different preferences. A baby is ready for solid food when he can be positioned upright for feeding, has lost the tongue thrust reflex that pushes the food right back out in younger babies, shows an interest in solid food, and can communicate when he doesn’t want something by closing his mouth or turning his head away.
Breastmilk is the perfect food for newborns, but it becomes inadequate in later infancy. It fails to provide the iron that babies need to prevent anemia, and it is lacking in a number of nutrients like vitamins A, C, D, and E and micronutrients like zinc and manganese. Our ancestors probably overcame this by feeding older infants meat and other foods, and the evidence shows that meat, egg yolks, and fish are good for babies. Vegetarian diets, especially vegan and macrobiotic diets, have been shown to result in nutrient deficiencies, stunted growth, muscle and fat wasting, and slower psychomotor development.
The risk of anemia can be counteracted by feeding infant cereals fortified with iron. Whole grains may be more nutritious, but refined grain cereals are a better source of iron. She recommends feeding babies a varied diet, avoiding sugar, and not adding salt. She found no evidence that organic food benefited children’s health. She emphasizes that the most important part of feeding isn’t the food: parents should relax and enjoy feeding and interacting with their babies.
Babies are amazing
She includes a chapter that amounts to a love letter to babies, urging parents to observe how their newborns explore, communicate, and learn. Newborns have special reflexes and are capable of more than most people realize. And they are unique individuals; parents need to learn to interpret their cues and respond appropriately.
In eight appendixes, she offers reassuring evidence-based answers to these questions:
- Are the ingredients in the vitamin K shot safe?
- Why is the HepB vaccine given at birth?
- Do we give too many vaccines too soon?
- Do vaccines cause autism?
- Do vaccines increase the risk of SIDS?
- Should we worry about the aluminum in vaccines?
- How do we know that babies need so much iron?
- Should we be concerned about arsenic in rice cereal?
This is science-based medicine writing at its best. Callahan doesn’t cherry-pick. She knows how to evaluate the entire body of research and put it into perspective along with practical parenting considerations. She enhances her message with a personal touch, including anecdotes about her own experiences as a new mother and about the experiences of her friends and family. If I had three thumbs, I would give this book a 3-thumbs-up recommendation. If every new parent could read this book, it would go a long way towards immunizing them against the misinformation they will inevitably encounter, misinformation that so often clouds their judgment and worries them unnecessarily.
This article was originally published in the Science-Based Medicine Blog.