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Your 40-Week-Old Baby
Updated on
September 14, 2023

Your 40-Week-Old Baby

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Your 40-Week-Old Baby.
Your 40-Week-Old Baby

The 9-Month Growth Spurt

Do those footie pajamas suddenly not zip? Nine months is a common time for your baby to have a growth spurt. And it may look like it happened overnight.

This is a huge time for development and physical growth. From sitting to crawling, pulling up to pincer grasping, there’s so much to be amazed by.

The telltale signs of a growth spurt (aside from an instant need for new clothes!) include:

  • Disrupted sleep or lots of sleep!
  • A spike in appetite. (If you’re breastfeeding, you may notice your kiddo wants to nurse more frequently, so follow their lead. And be sure to eat and drink more to keep up.)
  • A shift in mood (you may find your happy camper to be more cranky than usual).

If your baby is going through a growth spurt, know that the crankiness/sleep issues won’t last forever—they typically last anywhere from 2-3 days to a week. Each baby develops on their own timeline, so you may find a growth spurt occurring a little earlier or later.

Development: Music Is Good for Babies!

Hanging out with a baby can get a little monotonous. No offense to those cuties, but one-sided convos aren’t always super stimulating for us adults. A fun way to shake things up (literally) is to turn on some music and have an impromptu dance party. You’ll be the one doing most of the moves, but even babies at this young age love listening to music and, of course, making their own.

Set out some musical toys like maracas, a tambourine, a xylophone and egg shakers and play your favorite tunes (because a baby won’t judge if there’s a lot of Taylor Swift on your playlist). You can also play kids songs. Baby Shark, anyone? Make DIY instruments with Tupperware, plastic bowls, spatulas and wooden spoons. Playing music in the car can help ease fussiness. And at bedtime, soothe your kiddo to sleep with classical music (which will help you unwind too).

Aside from the benefits of being exposed to new sounds and words, babies may actually have an innate sense of rhythm. A study by the University of Nevada-Las Vegas shows that babies notice when someone dances off beat (so you better bring your A-game!). Researchers showed babies a series of videos featuring a woman dancing. In one video, the dancer’s moves synced up with the music; in the other, she moved out of sync. Babies as young as 8½ months noticed the difference between good dancing and bad, looking at the screen longer when the woman was moving off beat.

So keep the tunes coming and watch as music becomes an even more interactive experience as your kiddo grows.

Ready to rock out? From keyboards to shakers, these are our favorite musical toys for babies and toddlers.

This information is provided for educational and entertainment purposes only. We do not accept any responsibility for any liability, loss or risk, personal or otherwise, incurred as a consequence, directly or indirectly, from any information or advice contained here. Babylist may earn compensation from affiliate links in this content. Learn more about how we write Babylist content and review products, as well as the Babylist Health Advisory Board.