Your 20 Week Old Baby's Development And Milestones

by Scary Mommy
Originally Published: 
20 week old baby

You officially have a 20 week old baby!

Great news! If he hasn’t started already, your baby might begin sleeping through the night right about now. Hallelujah! Finally, you are one step closer to not looking like an extra on The Walking Dead and can resume conducting yourself in a manner consistent with humanity.

A word of caution, though: Don’t get too excited. Many pediatricians consider “sleeping through the night” to be a mere five hours, so unless you want to endure a fresh hell unlike any other you’ve experienced to date, you should probably save the whiskey shots and table dancing for another 16 years or so.

Your 20 Week Old Baby’s Development & Growth Milestones

Want to try out some of that slap-stick comedy you’ve been dying to perform? Now’s the perfect time to beta test your material on your baby. That’s because at this age, a baby’s brain development is to the point where he’ll laugh at all those silly things you do. So give him your best cross-eyes and goofy tongue. Just don’t be mad when he laughs uncontrollably after you accidentally slip and fall on the kitchen floor because somebody (not pointing fingers, but it was totally your partner) spilled water and neglected to clean it up.

As your baby gets older, they should be settling into a more regular sleep schedule, getting in about 12 to 15 hours a night. This is great news for you. Now that baby may be getting a bit more nighttime shut-eye, you should, too. It’s tempting to want to dive into other things, such as paying those bills that have been staring you down for a week or actually showering for the first time in days, but try to get some rest. Besides, nobody thinks you smell as bad as you think you smell. (Probably.)

Your 20 Week Old Baby’s Physical, Social, And Cognitive Milestones

If you thought your baby was developing quickly as a newborn, then this period will seem like a veritable free-for-all of milestones, with a new one popping up every day. And you’re not wrong, according to, the American Academy of Pediatric finds that most five months old babies exhibit one or more of the following:

  • Rolling from their back to belly and belly to back
  • While standing with support, accepts entire weight with legs
  • Reaches for nearby toys while on tummy
  • While lying on their back, the baby reaches both hands to play with feet
  • While lying on back, the baby transfers a toy from one hand to the other
  • The baby uses both hands to explore toys
  • Generally happy when not hungry or tired
  • Brings hands and objects to mouth
  • The baby is calms down with rocking, touching, and gentle sounds
  • Is not upset or frightened by everyday sounds
  • Enjoys a variety of movements
  • Is responsive or vocalizing in response to playful interaction
  • Turns head toward sounds
  • Uses hands to support self while sitting

Your 20 Week Old Baby’s Health

With your next well-visit only a few weeks away, your tot is due for a series of vaccines to keep her up to date. Per the CDC, look out for side-effects like fussiness, irritability, a low-grade fever, and soreness at the site of the injections for a day or two after the appointment.

This article was originally published in 2015.

Read More:

20 Weeks Of Sleep Deprivation

Your 21 Week Old Baby’s Development And Milestones

Dear New Mom: Please Take A Shower

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