Emily Oster (@profemilyoster)

The list of what not to do while pregnant feels longer than a CVS receipt. At ParentData, we want to empower you to make the right decisions for you. What an amazing group of women, and an honor to speak at the #MomsFirstSummit debunking parenting myths. What are some pregnancy rules you chose…

The alcohol level in your milk reflects the alcohol level in your bloodstream. The amount of alcohol passing through your breast milk is quite low even if you were to drink large quantities (which I don’t recommend, mainly because you probably can’t parent well after four tequila shots). And if…

Ever wondered if you can safely use leftover baby formula? 🍼 The CDC says to throw out unused formula immediately because of the risk of bacterial growth. However, research suggests that bacterial concentrations do not appreciably increase after 3, 12, or even 24 hours at refrigerator…

Election night is when counting starts, not when it ends. Ballots get counted, checked, and certified, and the timing varies by state. Early numbers can shift as more votes come in, and that’s normal. #CountEveryVote

There’s real data on this: making voting social gets more people to the polls. Election Day is Tuesday, Nov. 3. Bring a friend, bring the kids, or find a party at the polls near you. Questions or issues while voting? 866-OUR-VOTE #partyatthepolls

You may have heard of the phrase "hurried child syndrome." Some people think it’s about rushing your kid out the door, but it actually refers to something else: pushing your children to grow up too fast by packing their schedules, layering on academic and athletic pressure, and treating them like…

I talk a lot about what you shouldn’t worry about – but one thing you shouldn’t ignore is drowning. Every week in the US, an estimated 9 kids under 5 die from unintentional drowning. This is a leading cause of death for young children, and summer is the highest risk time. Worrying alone isn’t…

If you've felt confused by all the conflicting parenting advice out there, you're not alone. No time-outs. Don't be too permissive. Don't be too strict. It's a lot. So I went back to the research. Time-outs are actually one of the most studied, evidence-based components of discipline, and there's…

Heading to a July 4th cookout? You can absolutely have a drink if you want to—even if you're breastfeeding. The research doesn't support the idea that one glass of wine or a cocktail means you need to skip nursing—or pump and dump. Here's what the data says: alcohol does pass into breast milk, but…

There have been two botulism outbreaks linked to infant formula in the past year, and many parents are asking whether they could be connected. Newly released information suggests they may be. Both ByHeart and Nara Organics sourced powdered milk from the same supplier, and that supplier has been…

White noise can help babies sleep, and it’s safe to use despite some common concerns. The key is keeping the volume at a safe level. You can use a decibel meter app on your phone to check that it’s below 70 dB—a quick, easy way to reassure yourself that the sound isn’t too loud. For more details…

We all hate wasting breastmilk—pouring out a half-finished bottle can feel painful. The good news: new data suggest it may be safe to use for longer than older guidelines recommend. Read the full findings on ParentData.org, and share your breastmilk storage experiences in the comments.

GLP-1s are everywhere, and so are the questions: Can they help you conceive? When should you stop before pregnancy? What if you get pregnant while taking one? And are they compatible with breastfeeding? The reassuring news is that we're starting to get better data. Some evidence suggests GLP-1s…

If you co-sleep with your baby, you should know two things can be true at once: bed-sharing does increase SIDS risk, and the size of that risk depends a lot on the circumstances. The biggest risks in the data are smoking, alcohol use, soft bedding, pillows, and falling asleep with a baby on a…

Replying to @Apple User994582776 COVID generally poses a much lower risk to children than to adults, so an annual booster may not be necessary for every child. For children who have never had COVID, around six months of age is a reasonable time to discuss vaccination with a pediatrician…

The vitamin K shot given at birth is sometimes caught up in broader fears around vaccines and medical interventions, but it’s important to separate those issues. Vitamin K is not a vaccine—it’s a vitamin newborns need to help their blood clot properly. Without it, babies are at risk for a rare but…

Replying to @Megan D'Arcy The question of how GLP-1s affect fertility isn’t actually an easy one to answer. What we do know is that there’s evidence GLP-1s may improve fertility in women, especially those with PCOS. So far, we also haven’t seen evidence of negative effects on babies. Still, it’s…

Replying to @Jess Michelle⚡️ One of the best things you can do before the baby arrives is create space for regular check-ins. This is a chance to talk about what’s feeling good, what’s feeling hard, and how you can support each other better. Those small conversations build stronger communication…

Replying to @🍉 Salmonella isn’t actually considered an elevated pregnancy-specific risk with sushi — it’s a general foodborne illness risk, like it is for everyone. The bigger concern in pregnancy is toxoplasmosis, which is more associated with undercooked meat and is a true increased-risk…

A key cornerstone of my household is two weekly emails. It sounds slightly ridiculous when I say it out loud, but it’s probably the single most useful organizational habit we’ve built as a family. Every Saturday, I send one laying out the week ahead: schedules, dinners, pickups, anything unusual…

Replying to @twistyT What's the best exercise postpartum? Usually, it’s the one that feels doable. Walking counts. Stretching counts. Even just 10 minutes. Any movement can be good movement. That said, postpartum is also a great time to see a pelvic floor physical therapist—not because something…

Bug season is here, and the advice on mosquitoes and ticks is actually pretty simple. For mosquitoes: use repellent with DEET. Yes, it’s safe for kids when used as directed, and it’s the most effective way to prevent bites. For ticks: repellent helps, but nightly tick checks matter most. The…

Replying to @SamGurlCorp Breastfeeding has many established benefits, but current data do not show a clear reduction in type 2 diabetes risk for mothers or children. Observed links with obesity or metabolic outcomes are likely driven by differences across families, not breastfeeding itself…

Replying to @twistyT How do you increase your milk supply? Increase demand. The more milk that’s removed, the more your body makes. So, feed or pump more often, don’t skip sessions, and make sure milk is well drained each time. If your baby isn’t transferring milk effectively, add a pump after or…

Should you redshirt your kindergartener, or start on time? Delaying kindergarten by a year can give kids a slight early edge. Not all school districts allow it, but the data suggests older students are a bit less likely to struggle with behavior or be flagged for issues like ADHD. These…

Replying to @Ashlee Kate There’s a claim that breastfeeding is linked to SIDS, but that idea comes from very weak evidence. Much of it is based on case-control studies, which compare infants who died with those who didn’t and look back at factors like feeding. This design is especially vulnerable…

Replying to @user9091944105574 Water safety is incredibly important, so it’s great to be thinking about it early on. The two most important steps you can take are straightforward. First, if you're going to be around a pool, make sure it has a fence. Second, always actively supervise children…

When kids actually understand how their rights work, they're more likely to engage, ask questions, and participate in their communities. That's exactly the idea behind Know Your Rights University, and it's why I'm excited to partner with @ACLU to tell you about it. KYR-U is a new animated series…

Replying to @Shannon Gerow What does the data say about room sharing? While the AAP recommends room sharing with a baby for the first six months to reduce the risk of SIDS, the evidence behind that recommendation is limited. Some higher-quality studies suggest that transitioning babies to their…

There’s a viral paper arguing smartphones are driving global test score declines. It’s a compelling narrative, but the data doesn’t hold up. The result hinges on comparing 2012 to 2022, which folds in the COVID period. Look at the pre-pandemic years, and countries with higher or lower smartphone…