21-Week-Old Baby
21-Week-Old Baby
Bits of your 21-week-old’s personality are emerging as baby continues to hit more milestones. Are they feisty and quick to get frustrated during tummy time? Are they quiet and content while watching you throughout the day? Whatever their personality, love them up! And be sure to narrate what you’re doing when they’re nearby. The more words they hear, the better for their language development. Plus, your voice is one of their most favorite things in the world. Read on for more about your 21-week old.
Growth
At 21 weeks old, baby boys in the 50th percentile weigh about 16.4 pounds, while girls clock in at about 15.1 pounds. The average length (aka height) is around 25.1 inches for girls and 25.8 for boys. Your child’s own metrics may be off compared to these averages, and that’s fine! Every baby grows at a different rate.
Emerging skills
Along with physical skills, your 21-week-old is working on their social-emotional development as well. Baby may be starting to distinguish between emotions just by the tone of your voice. They’re also getting better at expressing their own emotions! Your little one might smile, squeal or giggle when they’re feeling happy, and frown, grunt or cry when they’re sad or frustrated. At this age, baby also recognizes familiar faces and knows whether someone is a stranger; they may even start to show signs of stranger anxiety, though it more commonly develops around 6 months or later.
A 21-week-old baby feeding schedule looks pretty similar to what baby has been doing for a while now. On average, breastfed babies eat about five or six times a day. Don’t be concerned if your nursing sessions are getting shorter—your little one is just becoming a more efficient eater! Formula-fed babies typically take in anywhere from 20 to 32 ounces a day. Watch for cues that they’re full, like turning their head away from the bottle.
Sleep
Some 21-week-olds still wake up once during the night to feed, especially breastfed babies. Even if you still wake to do a feeding session, your little one is now likely sleeping for five to six hours at a time, so you can hopefully get some quality shuteye. You might be gearing up for (or are in the middle of) sleep training, which can help improve the sleep quality for the whole family.
As for mid-day snoozes, 21-week-old babies typically nap two or three times a day, and they’ll let you know they’re tired by rubbing their eyes, drooping their heads or acting fussy. By sticking to a regular routine, their bodies will be primed for sleep when naptime rolls around. Babies at this age need between 12 and 16 hours of sleep per day.
Common ailments
Fever
It’s bound to happen at some point, but plenty of parents get a bit panicky when baby gets their first fever. Don’t fret! A temperature of 100.4 degrees Fahrenheit or higher is considered a fever. There are lots of different thermometer types out there, but the best way to get an accurate temp reading on a baby is with a rectal thermometer. Call your pediatrician to get guidance on how to treat the fever. Keeping your kiddo hydrated with breast milk or formula will be super important. You’ll also want to keep them as comfortable as possible: Try giving them a lukewarm sponge both, dress them in light layers and, if needed, give them a dose of Infant Tylenol.
When should baby sleep through the night?
Better nights are coming! Every baby is different, and there’s no specific age when all babies start sleeping through the night. But your 21-week-old should be able to last a few hours now without waking. A five- to six-hour stretch of nighttime sleep is considered good at this age, and they’ll progress to about nine hours when they’re between 6 and 8 months old.
If baby wakes, try letting them self-soothe for a few minutes before going in. Whenever you feed at night, keep it all business: low lights, no chatting or loud interaction. This distinction will help baby realize that it’s time for sleep. You can also look into the different methods of sleep training; the Cry It Out Method is a popular one but it’s not the only approach! See what works for your family.
When do babies say their first word?
Did baby just say “da da?” You’re not hearing things! But chances are, they’re not intentionally saying “daddy.” Your 21-week-old baby is babbling up a storm and experimenting with consonant-vowel combos, and that syllabic repetition may sound like words you know—but real talking won’t come until your child is closer to a year old. In the meantime, keep reading, chatting and singing to them to help boost their language development.
Baby sleeping on their stomach
Your 21-week-old is probably mastering the roll—and they’re practicing day and night. You know you’re supposed to put baby to sleep on their back, but what happens when they roll over onto their tummy in the middle of the night? Here’s the good news: Once baby is capable of rolling over on their own and has good head and neck control, it’s fine to leave them as they are. (But as soon as they’re showing signs of rolling, it’s time to stop swaddling them for safety purposes.) Rest assured, there’s no need to constantly wake to check on them or turn them over. That said, you should still place baby to sleep on their back until they turn one year old.
Does baby still need tummy time?
Yes! Even if baby can now roll over on their own, 21-week-olds should still be spending supervised time on their tummy. It helps strengthen baby’s arms, chest and back muscles and gives them an opportunity to practice lifting their head and chest higher and higher. When you first started, you probably did tummy time with baby for just a few minutes two or three times a day. Now that they’re older, you should be aiming for a total of 60 to 90 minutes a day.
- Get a sitter. Baby is at a prime social age right now, so take advantage of it! Get used to leaving your 21-week-old with your parents, in-laws, a trusted neighbor or sitter. Taking a few hours away from your child goes a long way for your mental well-being—and it’s good for baby too. Having them mingle with other people helps support their social development. Plus, there’s nothing like seeing their face light up when you walk through the door!
- Activity center. Now that baby is able to sit upright while supported and reach for objects, it’s a great time to introduce an activity jumper or chair. Under supervision, baby can sit safely contained and thoroughly entertained by the attached toys and activity features while you use your free hands to read a book, wash the dishes or tackle one of the other million things on your to-do list.
- 5-month-old toys. Your little one is learning facial expressions, grabbing toys and seeing in full color—so make sure you offer them playthings that help support their development. Mirrors, clutching toys and brightly colored books make great toys for a 5-month-old.
Ready to have a splashing good time? Cue up some sensory play with baby. Take out a baking tray and fill it with water, then add a teething ring or other lightweight toy that can float. At this age, your little one is likely starting to reach out and grab objects. So not only with your 21-week-old enjoy splashing in the water, but they’ll have to work at tracking the moving toy with their eyes and exercise hand-eye coordination to grab the plaything.
Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.
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