Cribsheet: A Data-Driven Guide to Better, More Relaxed Parenting, from Birth to Preschool (The ParentData Book 2)

by Emily Oster

But it illustrates what will be one of the great themes of your parenting life: you have way less control than you think you do.

The answer is that you do have choices, even if not control, and these choices are important.

The problem is that the atmosphere around parenting rarely frames these choices in a way that gives parents autonomy.

There are lines you shouldn’t cross with young children, but there are many more gray areas. Thinking about our choices in cost/benefit terms helps take some of the stress off a decision.

There was a time when women would stay in the hospital for a week or even ten days to recover after giving birth, but that time has decidedly ended.

In particular, baby-friendly hospitals must follow a ten-point plan designed to improve breastfeeding.

These tenets include things like not giving infants formula unless medically indicated, not giving pacifiers, and informing all pregnant women about the benefits of breastfeeding.

Babies who cry a lot are often described as “colicky.” Infantile colic isn’t a biological diagnosis like strep throat, but a label we give to babies who cry a lot for no identifiable reason. A common definition of colic (although not the only one) is the rule of three: unexplained crying for more than three hours a day for more than three days a week for more than three weeks.

Based on this definition, colic is pretty rare. In one study of 3,300 babies, researchers found that at one month of age, 2.2 percent of babies fit the “rule of three” colic definition; this is similar at three months.

As you relax the definition, the shares go up. For example, if you look for babies who cry more than three hours a day for more than three days a week for more than one week (this is like the rule of 3–3-1), this share is 9 percent at one month. If you rely on parental reports that the infant “cries a lot,” the share is close to 20 percent.

Two treatments have some known success with colic. One is supplementation with a probiotic, which a number of studies have shown to reduce crying. These effects seem to show up only in breastfed infants.

In contrast, if your two-week-old has even a low fever, you’ll need to take them to the hospital, where they’ll be subjected to lab tests—likely including a lumbar puncture (spinal tap)—given antibiotics, and admitted as an inpatient. With very young babies, doctors have a harder time distinguishing between high- and low-risk fevers. Babies in this group are somewhat more susceptible to bacterial infections, including meningitis, which is extremely serious. Somewhere between 3 and 20 percent of infants under a month old who come to the doctor with a fever have a bacterial infection.14 These are mostly urinary tract infections, but they must be treated, and reasonably quickly.

But the world is oddly lacking in discussions of what happens, physically, to Mom after the baby arrives. Before the baby, you’re a vessel to be cherished and protected. After the baby, you’re a lactation-oriented baby accessory.

This omission is problematic, since it fails to inform women about what to expect after you’re expecting. Physical recovery from childbirth is not always straightforward, and even in the best of circumstances, it’s messy. Hence, the ice diaper. In this

There are two other considerations. First, contraception: Even if you are breastfeeding and just had a baby three weeks ago, you can get pregnant. Most people do not plan babies ten months apart, so unless you have, make sure you are using some kind of birth control. (And think carefully about what type: some kinds of birth control, specifically some birth control pills, can interfere with milk production.)

With anxiety, it can be hard to know where the line is between normal parental worry and obsessive worry. If anxiety is interfering with your ability to enjoy spending time with your baby, if it is occupying all your thoughts and preventing you from sleeping—that is over the line.

In particular, as I mentioned in the introduction, most studies of breastfeeding are biased by the fact that women who breastfeed are typically different from those who do not. In the US, and most developed countries, more educated and richer women are more likely to nurse their babies.

SIDS is rare; ear infections and colds are common. Your kids will get colds for sure, whether you breastfeed or not. SIDS deaths, in contrast, occur in about 1 of every 1,800 births; among babies with no other risk factors (not premature, not sleeping on their stomachs), this is perhaps 1 in 10,000.13

In fact, it does take longer than that for many women. The graph on this page—from a study of 2,500 women—shows the distribution of days from baby’s birth to milk production. Almost a quarter of women have milk production delayed beyond three days. This is even higher—about 35 percent—for first-time mothers.

In addition to pain, an issue with oversupply is that when the baby does start to nurse, the milk may come very fast and overwhelm him, making it hard to actually eat. Basically, it is like you trying to drink from a firehose. Pumping for a couple of minutes—or hand-expressing milk—right before you nurse can help with this problem. It will also improve as the baby gets bigger and the oversupply problems calm down.

This paper cautions that drinking four drinks quickly will impair your ability to parent and is not healthy, so it should be avoided, but the issue isn’t alcohol in your breast milk. Therefore, there is no need to pump and dump. The milk has the same alcohol concentration as your blood. As that goes down, so does the milk alcohol level. It isn’t stored in the milk.

There is now a product called the Freemie, which is a pumping system where the cups effectively fit inside your bra and also collect the milk. The key, I think, is that the pump motor itself is quite small so you can store it in a pocket or clip it to your clothing.

There are basically three reasons to use a breast pump. Let’s review.

Finally, the main thing women use the pump for is to replace breastfeeding sessions after they’re back at work. The idea is that you pump at approximately the same times the baby would eat, and they eat what you pump the next day. If you are a prolific pumper, you may pump enough extra to freeze.

The causes of SIDS are not well understood. It seems to occur when a baby spontaneously stops breathing and doesn’t start again. It is more common in vulnerable infants—premature babies, for example—and in boys. Among the most

Until the early 1990s, the most common sleeping position for infants—in the US and elsewhere—was on their stomach. The reason for this is likely that many infants sleep better this way—they don’t wake up as much.1 However, as early as the 1970s, there were some clues that stomach sleeping was associated with a higher risk of SIDS.2 Studies comparing populations with different sleeping patterns showed worse outcomes for the group that slept on their stomach. These

This means there is seemingly no benefit to extending room sharing for so long.

In a 2017 study, researchers evaluated whether a child’s sleeping in a room with a parent made for worse sleep. They found that it did. At four months old, total sleep time was similar for babies sleeping in a parents’ room and those sleeping in their own room, but sleep was more consolidated (i.e., in longer stretches) for those in the latter group. This makes sense: their own room will be quieter.

Across virtually all studies of sleep location, the one thing that jumps out as really, really risky is babies sharing a sofa with an adult. Death rates as a result of this behavior are twenty to sixty times higher than the baseline risk.

Ferber, for instance, says that at six months, a baby should sleep a total of about 13 hours: 9.25 hours at night, and two 1- to 2-hour naps. Weissbluth suggests this same six-month-old should sleep a total of about 14 hours, but with more of those hours falling at night: 12 hours at night, and two 1-hour naps. This is a 3-hour difference in the suggested nighttime sleep.

Longer nighttime sleep develops around two months. Move to three regular naps around four months. Move to two regular naps around nine months. Move to one regular nap around fifteen to eighteen months. Drop napping around age three.

But I’d like to encourage you to also think about 2. That is, you should think about whether you want to work. It is common for people to say they work “because I have to” or stay home “because I have to.” And in either case, that can sometimes be true. But I think it is not true as much as people say it. And this is a problem.

We can start with a place where we do have some causal evidence: the impact of a parent staying home in the first couple of years. I’ll talk below about maternity leave specifically, and the question of, say, no maternity leave versus six weeks or three months of leave.

But there is also a set of literature that estimates whether it matters for kids if parents are home for, say, a year versus six months, or fifteen months versus a year.

The bottom line from this literature is that these parental-leave extensions have no effect on child outcomes.1 No effects on children’s test scores in school, on income later in life, or on anything else.

Second, studies tend to find that the impacts of both parents working are positive (i.e., working is better) for kids from poorer families, and less positive (or even slightly negative) for children from richer families.

The authors found that attending higher-quality day care strongly correlated with better child language development: kids who went to better day cares seem to talk more. When they looked at behavior problems, though, there did not seem to be a relationship to day-care quality in either direction—the effect was about zero.

The researchers doing this study followed the children through sixth grade and continued to find that day-care quality is associated with better vocabulary outcomes, but not with behavior.

and adults seem to have a positive and loving relationship?

On the cognitive side, the results are mixed. More months in day care before eighteen months are associated with slightly lower cognitive scores by four and a half years old, but more time in care after that is associated with higher cognitive outcomes.

It is hard to know why this is. It could be that very early on the one-on-one attention enhances early language development, but at older ages, children in day care are likely to spend more time on skills like letters, numbers, and social integration than children cared for by nannies or stay-at-home parents. But this is speculation. It is also possible that these are just correlations—that they are not causal at all.

Studies that combine this suggest that, overall, the effect is positive—that kids who are in day care for more time over this entire period have better languag...

There are various other things evaluated in these studies. One is “infant attachment.” Are kids in day care less attached to their moms? No, they are not. Quality of parenting matters for this, but day-care time makes no difference.

A final data-driven comparison is with illness. Kids who are in day care are more likely to get sick.9 These are not serious illnesses, more like colds and fevers, stomach flu, and so on. On the plus side, these early exposures seem to confer some immunity, with children who were in day care for more years as toddlers having fewer colds in early elementary school.

There isn’t an easy choice. But by being explicit about what else you’d do with the money, you can at least frame the decision a bit more concretely: Would you rather have your own nanny, or two vacations a year, or more retirement savings?

One of the best pieces of parenting advice I got from my friend Nancy was this: Regardless of what childcare you choose, have a plan for who is in charge when the nanny or the kid is sick.

Of course, there is yet a third solution, advocated more strongly in the attachment-parenting community, that you should not be doing this at all. This philosophy is often linked with William Sears, a Californian doctor with more than thirty parenting books to his name.

Even if you do not think there are long-term consequences of sleep training, it is unpleasant to do—most parents do not like to listen to their children cry.

Good news: yes, this method works for improving sleep.

It is worth noting that most of these studies—and, indeed, virtually all sleep books—recommend a “bedtime routine” as part of any sleep intervention.