As baby’s independence increases, so does their exploration of the world around them—which includes everything from household objects to pets to the playground. Here’s what else you can expect from 40-week-old baby development, milestones and more.

40-Week-Old Baby Milestones & Development

Growth

The average weight for baby at 40 weeks is 18.3 pounds for girls and 19.8 pounds for boys. The average length at this stage is 27.8 inches for girls and 28.4 inches for boys. Of course, every baby is different: Baby’s growth depends on many factors, including genetics, diet and overall health. Your child’s pediatrician will follow baby’s unique growth curve to make sure everything is on track.

Emerging skills

Baby’s working on an impressive range of social, communication, cognitive and physical milestones. This might include looking for objects that you hide during games (so keep challenging them!), banging things together to explore cause-and-effect (oh how fun for your ears), showing a variety of emotions and more. They’ve also likely begun responding to their name. Physically, baby’s pulling up to stand and maybe even starting to take a few steps while holding the edge of the couch or a low table. Make sure baby’s holding on to stable objects—not potted plants, floor lamps and the like.

40-Week-Old Baby Health

Feeding

By 40 weeks, it’s likely that baby’s exploration of solid foods is well underway, whether you started off with pureed foods, baby-led weaning or some combination of the two. Make mealtime fun by offering food in various colors, like orange sweet potato, red peppers and yellow squash.

Sleep

Although every baby is different, on average your 40-week-old needs 12 to 16 hours of sleep every 24 hours, including nine to 12 hours at night and the rest spread out between a morning and afternoon nap. It’s totally normal for baby to wake up in the middle of the night for any number of reasons, including simply seeking comfort. Continue to set the stage for good sleep habits by sticking to a consistent bedtime routine.

40-Week-Old Baby FAQs

Can houseplants be dangerous for baby?

Now that your little one is more mobile, it’s extra important to be mindful of which plants you have and where you put them. As part of your baby proofing, move plants high up out of reach. It’s also a good idea to brush up on which houseplants can be poisonous for children. Philodendron, pothos, peace lilies, caladium and English ivy are all popular houseplants that can be toxic if eaten.

Should I teach baby sign language?

Absolutely! It can be frustrating for baby to communicate when they can’t yet fully verbalize what they need. Teaching baby simple sign language is a useful tool that can lead to improved communication and increase your bond with baby.

Timely 40-Week Topics

Separation anxiety

If baby bursts into tears when you step out of a room or hand them to someone else, they may be dealing with separation anxiety, which tends to appear when babies are around 9 months old. Some other signs might be if baby clings to you (or your partner) and doesn't welcome attention from others. Don't worry, it's not a bad thing! As hard as it is to see your little one in tears, it's natural for baby to want to stay with their caregiver, and it's an indication of a strong bond. To ease the separation, time your departure for when baby is fed and well-rested, keep your goodbyes calm and cheery and make it quick—the more drawn out it is, the more time your child has to become anxious. The tears will stop, and they'll be so happy to see you when you return.

Safety around pets

Your “fur baby” is an important part of the family, and there are a few things you can do to make sure your pet and baby live in harmony, especially as baby gets bigger. Create a baby-free zone for your pet (and vice versa, of course!), and give them a place to hide if they need a break. Make sure they’re getting enough exercise too. Also, model how to touch animals gently for baby, and firmly tell them “no” if they’re being too rough. Practice good hygiene around your pet, always washing your and baby’s hands after touching them. Lastly, don’t leave baby alone with your pet.

Parent Tips

• Carve out some just-the-two-of-us time. Maybe you expected having a newborn to bring new challenges to your relationship, but for things to get back to normal once baby got a bit older. Except…life is still kind of crazy, and sometimes it feels like you and your partner are roommates who argue over things like who was supposed to order a new box of diapers. It's definitely normal for your relationship to change after baby. But it’s also a good idea to actively work on your communication—and to plan regular date nights.

• Listen to some adult music. No, not that Cocomelon tune you have on repeat in your head. We’re talking about the music you used to listen to before you had baby. Turn on your favorite artists and jam out! This is a great mood booster for those long, stressful days.

Products You Need at 40 Weeks

• Convertible car seat. Your infant car seat has been a trusted piece of baby gear, but at 40 weeks old, baby might be getting a bit big for it! Every car seat has a specific height and weight limit, so check the manufacturer’s website, but some kids can outgrow their infant car seat as early as 9 months. If that’s the case, it’s time to switch to a rear-facing convertible car seat.
• Date night ideas. Ready to spice things up? If you’re eager to spend more time with your partner but having trouble deciding what to do, these fun ideas, conveniently delivered to your door, might just do the trick.

Weekly Activity for Your 40-Week-Old Baby

Play “put it back” by dumping blocks from a container and putting them back in together. This simple activity will help with baby’s fine motor skills, hand-eye coordination and problem-solving.