Q&A: Tylenol and vaccination, periods, car seat mirrors, and preemies

Ask ParentData

It’s Q&A day!

Today’s first question is available to all subscribers (about whether girls are getting their period younger), and there are a few bonus ones behind the paywall (about Tylenol after a baby’s vaccination, infant car safety, and steroids for preterm birth risk).

Enjoy! And remember, you can submit questions for future weeks here.

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Is it true that nowadays girls are having their period younger than before, like around 8 to 10 years old? Is there any data supporting that? And if that is true, what is the reason behind it, and how to be prepared if you are the parent and the girl in case that happens?

—Mom-and-Dad-to-be of a girl

Great question. 

Over the past several decades, some parts of puberty have started to happen at younger ages. This includes breast growth and penis and testicle growth. However: periods have not moved in the same way. The average age of menarche (the first period) is 12 to 12.5, similar to how it was when we were kids. There is variation in these ages — girls can start their period as young as 8, but it’s not common. 

Regardless of the timing, here is my best advice for how to be prepared for puberty. Read the new book This Is So Awkward by Cara Natterson and Vanessa Kroll Bennett. If you want a preview, subscribe to the ParentData podcast, where tomorrow’s episode is an interview with this awesome team. We talk about ages of periods, body hair, and all of the other things you want to be ready for. 

Does giving a baby Tylenol after a vaccination dampen their immune response and make the vaccine less effective? How does Tylenol reduce inflammation and fever without making a shot less effective?

—Dewey user