The first time your 39 week old baby attempts to climb the stairs, you will feel two things simultaneously: pride and raw terror. One moment they are crawling across the living room floor, and the next they have planted both hands on the bottom step, hauled one knee up, and are reaching for the second step with the focused determination of someone summiting a mountain. Week 39 marks the arrival of the climbing instinct, a developmental leap that changes your daily life in immediate, practical ways. Your baby's balance while standing is also improving noticeably, pointing has become a primary communication tool, and they are beginning to follow simple instructions -- sometimes. Here is everything you need to know about this high-energy, high-adventure week.
Quick Answer
At 39 weeks, babies begin climbing stairs, cushions, and low furniture. Standing balance improves significantly, with longer periods of unsupported standing. Pointing becomes a deliberate communication method, and babies start understanding and occasionally following simple instructions like "give it to me" or "come here."
What's Happening at Week 39
Physical Development
Climbing is the new frontier. Your 39-week-old has spent weeks building upper body strength through crawling and pulling to stand, and now that strength meets ambition. Stairs are the most obvious target, but babies at this age will also attempt couch cushions, low step stools, open dishwasher doors, and anything else that presents a vertical challenge. According to the American Academy of Pediatrics, stair climbing typically emerges between 9 and 12 months, and the ascending skill develops well before the descending skill -- which is exactly why this milestone demands immediate safety attention.
Standing balance takes a visible step forward at week 39. Many babies can now stand unsupported for five to ten seconds, and some are beginning to shift weight from foot to foot while standing -- a subtle but critical precursor to walking. You may notice your baby standing in the middle of the room, hands free, swaying gently, looking surprised at their own achievement. These balance sessions get longer every day as the vestibular system and core muscles strengthen through repetition.
Crawling itself has become so efficient that it is almost an afterthought. Your baby moves across rooms at startling speed, navigates around obstacles, and transitions fluidly between crawling, sitting, pulling up, and cruising without pause. This movement fluency frees cognitive bandwidth for higher-level tasks like exploring new terrain -- which is precisely why climbing appears now.
Cognitive Development
Pointing transforms from a vague gesture into a precise communication tool at 39 weeks. Your baby now points at specific objects and then looks back at you, clearly expecting a response. Point at the dog: look at you. Point at a banana on the counter: look at you. This "declarative pointing" -- pointing to share interest rather than just to request -- is a milestone that developmental researchers consider one of the strongest predictors of language development. A study referenced by the National Institutes of Health found that the frequency of declarative pointing at 9 to 12 months positively correlates with vocabulary size at 24 months.
Simple instruction comprehension is emerging. When you say "give it to me" and extend your hand, your baby may actually hand over the toy. When you say "come here," they may crawl toward you. Compliance is inconsistent -- sometimes they understand perfectly and simply choose not to follow through -- but the comprehension itself is genuine. They are processing your words, connecting them to actions, and making decisions about whether to respond.
Social and Emotional Development
Your baby's social world is expanding in complexity. They are beginning to observe and imitate more nuanced behaviors -- stirring a spoon in a cup, holding a phone to their ear, wiping a surface with a cloth. These imitative actions show that your baby is not just watching you but building mental models of how the world works. Parents in our community often tell us that week 39 is when they first feel truly "watched" by their baby -- every action you take is being catalogued and filed away for future imitation.
Best Activities for Week 39
1. Supervised Stair Practice
Rather than only blocking stair access, set aside time each day for supervised climbing. Place your baby at the bottom of a carpeted staircase and stay directly behind them as they climb two or three steps. Then help them turn around and practice coming back down feet-first on their belly. Teaching the descent is critical -- babies who only practice going up will eventually attempt to come down headfirst, which is dangerous.
2. Cushion Mountain
Build a climbing course from couch cushions, firm pillows, and rolled blankets on the floor. Arrange them at varying heights so your baby can practice climbing up, over, and down soft obstacles. This satisfies the climbing urge in a controlled environment and builds core strength, balance, and spatial awareness. Place a favorite toy at the "summit" for motivation.
3. Point-and-Name Game
When your baby points at something, respond immediately and enthusiastically: "Yes! That is a bird! Bird!" This positive feedback loop reinforces the power of pointing as communication and builds vocabulary simultaneously. Aim to name the object within two seconds of the point -- the faster the response, the stronger the neural connection between gesture and word.
4. Simple Instruction Relay
Practice one-step instructions throughout the day: "Put the block in the cup." "Give the spoon to Daddy." "Push the ball." Keep instructions simple, use gestures to support the words, and celebrate every successful follow-through. If your baby does not respond, demonstrate the action yourself and try again -- modeling is more effective than repetition at this age.
5. Standing Balance Play
While your baby stands unsupported, offer them a toy that requires two hands -- a large ball, a wide book, a stuffed animal. Accepting a two-handed toy while standing forces your baby to maintain balance without using their hands for support, which accelerates vestibular development. Stay close enough to catch them but far enough that they do not reach for you reflexively.
Creating the Right Environment
A climbing baby changes the safety calculus of your entire home. Every low surface becomes a launchpad, and the dismount is almost never graceful. At 39 weeks, your baby is ascending couch cushions, crawling over pillows, pulling up on anything within reach, and standing unsupported for increasing stretches -- all of which end in falls more often than not. The floor around every climbable surface is now an active landing zone.
A PocoKoko memory foam play rug provides 1.3 inches of CertiPUR-US certified cushioning across the entire area where your baby climbs, stands, and inevitably tumbles. Unlike foam tiles that separate at the seams or shift when pushed, a PocoKoko rug stays flat and anchored with its non-slip backing -- giving your baby stable footing for standing practice and a soft landing for every fall. The machine-washable cover is essential now that your baby drags food, drool, and outdoor debris across every surface they touch. Designed to look like a stylish area rug, it earns permanent real estate in your living room rather than hiding in a closet between play sessions.
When to Talk to Your Pediatrician
Week 39 sits within a wide window of normal development, and not every baby will be climbing or standing unsupported yet. However, the AAP recommends contacting your pediatrician if your baby cannot bear weight on their legs when supported, does not sit independently, shows no interest in moving toward objects or people, does not use gestures like pointing or waving, does not respond to their name consistently, or appears to have lost skills they previously had. Trust your instincts -- if something feels off, your pediatrician wants to hear about it sooner rather than later.
FAQ
What should a 39 week old baby be doing?
At 39 weeks, most babies are crawling confidently, cruising along furniture, and beginning to climb low surfaces like stairs and couch cushions. Many stand unsupported for several seconds. Pointing becomes a primary way to communicate wants and interests, and babies begin following simple one-step instructions. Some may take supported steps while holding your hands. Fine motor skills allow more deliberate manipulation of objects. Development varies widely at this age, so not every baby will hit every milestone at the same time.
When should I worry about my baby not standing at 39 weeks?
Standing independently is not expected at 39 weeks -- the typical range for unsupported standing is 9 to 12 months, and many healthy babies do not stand alone until closer to their first birthday. What matters more is that your baby is bearing weight on their legs when held upright and showing interest in pulling to stand. If your baby does not bear weight on their legs at all or shows no interest in upright positions, mention it to your pediatrician. The CDC developmental milestones provide a helpful framework, but remember that ranges exist for a reason.
How do I keep my climbing 39 week old safe?
Install baby gates at the top and bottom of all staircases immediately. Anchor all freestanding furniture -- bookshelves, dressers, TV stands -- to the wall, since climbing babies can topple unsecured furniture. Remove any objects from low surfaces that could hurt your baby if pulled down. Supervise climbing attempts rather than preventing all climbing, as the skill develops best with practice. Cushion landing zones around furniture with padded mats, and teach your baby to descend stairs and furniture feet-first on their belly.
Related Milestones
- Previous: Baby Week 38 Development
- Next: Baby Week 40 Development
- Monthly: 9-Month-Old Milestones
- Activity Guide: Best Activities for 9-Month-Olds
- Hub: Baby Milestones Hub
Written by the PocoKoko Team -- parents, product designers, and child safety researchers dedicated to creating safer floors for families.