A guide to child milestones and development checkpoints

Watching your child grow is one of the greatest joys of parenthood. Every smile, every new sound, and every wobbly step feels like a milestone worth celebrating. But alongside that joy can come questions: Is my baby developing “on time”? What should I look out for?

In this guide, created in collaboration with How About Mom, we explore the key child development milestones and developmental checkpoints by age. All the way from the newborn stage to your kids' preschool years. With expert-backed insights, combined with relatable parenting experiences, this article is designed to give you clarity and confidence.

Why milestones matter

It's important to keep in mind that developmental milestones are not strict deadlines. Milestones are more like a roadmap, showing typical skills children tend to master at certain ages, such as smiling, rolling, or saying their first words.

Child development doesn’t follow a straight line. As UNICEF explains, milestones act as "guideposts" rather than exams – giving you perspective, not pressure. A baby might learn to sit before they roll or focus on language before movement. Periods of fussiness, such as growth spurts or sleep regressions, often signal that a developmental leap is underway. These phases can be challenging, but they are also signs of healthy growth.

What are the key developmental milestones by age?

Newborn to 3 months

The first 3 months of your newborn’s life are called the "fourth trimester". After 3 trimesters of pregnancy, this fourth trimester represents a crucial period of physical and emotional adjustment for both the newborn and the parents. Babies are discovering life outside the womb and beginning to interact with their environment.

Unfortunately, babies aren’t born with a manual. You are going to discover the character and preferences of your baby. Some days your baby may feed more frequently, sleep less, or be unusually fussy. These cluster feeding days often coincide with growth spurts. Exhausting for parents, but a sign that development is on track.

Physical developments during the first 3 months:

• Reflexes such as sucking, grasping, and startle are present at birth
• By around 2 months, babies may briefly lift their head during tummy time
• Movements become more purposeful, with arms and legs stretching and kicking

Social and emotional developments during the first 3 months:

• The first real smile of your baby might appear around 6–8 weeks (yes, that smile that makes you forget the broken night before)
• Your baby recognizes familiar voices and may become quiet when spoken to

Cognitive developments during the first 3 months:

• Your little one begins to track objects with their eyes
• Showing some recognition of parents’ voices and soothing tones

4 to 6 months

It's an important milestone: your little one is almost half a year old! At 4 months, your baby starts to move with purpose and interact with others more socially. By 6 months, your little one has grown from a tiny newborn into a little adventurer.

Physical developments 4 to 6 months:

• Holding up head steady without support
• May roll from tummy to back or back to tummy
• Starting to reach, grasp, and bring objects to the mouth

Social and emotional developments 4 to 6 months:

• Smiling and laughing in response to interaction
• Distinguishing between familiar and unfamiliar faces

Cognitive developments 4 to 6 months:

• Beginning to understand cause and effect (for instance, shaking a rattle makes noise)
• Watching moving objects with growing curiosity

7 to 12 months

The second half of the first year is full of exploration. Your baby may also begin to say their first words – or more accurately, their first sounds.

Physical developments 7 to 12 months:

• Sitting without support
• Crawling or pulling to stand. They may take their first steps at around 12 months
• Using the pincer grasp (thumb and finger) to pick up small items

Social and emotional developments 7 to 12 months:

• Waving, clapping, or using gestures to communicate
• Stranger anxiety may appear, which is a normal developmental phase for your baby. Don’t worry: it's a sign of healthy cognitive and social-emotional development, indicating a strong attachment to familiar caregivers

Cognitive developments 7 to 12 months:

• Recognizing familiar words like “bye-bye” or their own name
• Understanding simple instructions with gestures
• May say his or her first words around 12 months

1 to 2 years (toddler stage)

Toddlers are curious explorers. This stage often feels like a whirlwind of first steps, first words, and big emotions.

Physical developments 1 to 2 years:

• Walking independently, then running and climbing
• Can start stacking blocks

Social and emotional developments 1 to 2 years:

• Playing alongside other children (“parallel play”)
• Showing independence, wanting to try things “by myself"

Cognitive developments 1 to 2 years:

• Their vocabulary grows rapidly: by 2 years, toddlers may use two-word phrases (“more milk”)
• Can follow simple instructions and identify objects

Good to remember as a parent with a toddler: frustration and tantrums are normal at this stage. They reflect your toddler’s growing desire to communicate and be independent. A full-swing tantrum in the supermarket aisle is not a sign of your parenting skills, but rather a common developmental phase.

3 to 4 years (preschool stage)

Your child continues to develop rapidly. The preschool years bring imagination, language, and social skills to the forefront. You might notice your child starts playing and interacting differently.

Physical developments 3 to 4 years:

• Climbing stairs with alternating feet
• Pedalling a tricycle or bike with training wheels
• Improved drawing skills, for instance, circles or simple figures

Social and emotional developments 3 to 4 years:

• Engaging in imaginative play (“pretend play”) at this age – "You’re the dinosaur, mommy!"
• Forming first friendships and learning to share

Cognitive developments 3 to 4 years:

• May speak in longer sentences
• Asking a lot of “why” questions
• Understanding concepts like colors, shapes, and counting

How to track your child’s development mindfully

You may or may not have recognized some of these developments with your own child. Use milestones as a guide, not a test. Focus on steady progress, not exact timing, and celebrate each small win – from grasping a toy to saying "mama". If it suits you, track growth with apps or a journal. Remember, development isn’t linear: regressions in sleep, feeding, or mood often come just before new skills emerge.

When to seek professional guidance

Are you worried about your child’s development? Trust your instincts. If you feel something is off, it’s always okay to ask. Key times to seek help include:

• When skills are lost (for example, if a child stops using words they once knew)
• If major milestones are delayed far beyond the expected age
• If your child struggles with feeding, movement, or connection to his or her surroundings

Pediatricians and healthcare providers use developmental checkpoints to guide support. Early attention can make a big difference, so don’t hesitate to reach out.

Supporting development with everyday tools

By creating a nurturing environment and providing a safe, loving, and stimulating space for your child, you're setting the foundation for growth. Safe play spaces and reliable strollers give babies the freedom to discover the world. Play and interaction are vital to growth. Regular routines around sleep and meals also provide comfort and stability for your little one.

At Bugaboo, we focus on parental products that help you navigate daily life with ease, with your child by your side. Our strollers and home solutions are made to adapt to your family's changing needs, helping you create memorable moments through each milestone.

FAQs about your child’s developmental milestones

What are the key child development milestones by age?

From smiling and rolling in infancy to walking, talking, and imaginative play in toddlerhood, milestones are guideposts for healthy growth. Key child development milestones include physical, cognitive, language, and social-emotional skills, with specific achievements for each age group.

How do I know if my child is meeting their developmental checkpoints?

Milestones are general guidelines. Children develop at different paces, and there is a normal range for meeting milestones. One child may be early in one area and take more time in another. That’s why it’s best to track progress over time, not single moments. Regular check-ins at healthcare visits also help.

What are red flags in child development?

Loss of skills, lack of interaction, or long delays in movement or speech are reasons to seek advice. If you, as a parent or caregiver, have a feeling that something isn't right with your child's development, don't hesitate to voice your concerns.

How can I support my baby’s motor and cognitive development?

Play, talk, cuddle, and give your child safe ways to explore their environment every day. These daily interactions set the foundation for your baby's development and growth.

When should I be concerned about missed milestones?

If several skills are delayed, or if your instincts tell you something is wrong, reach out to a professional.

Final thoughts: empowering parenthood through awareness

Understanding child development milestones empowers you as a parent. It helps you celebrate progress, navigate challenges, and know when to ask for support. Most of all, it reminds you that your love, patience, and presence are the foundation for your child’s confident start in life.

About How About Mom

This Guide to Child Milestones and Development Checkpoints was written by the Dutch platform How About Mom. We have a clear mission: to provide new mothers the support they need – during pregnancy, childbirth, and the postpartum period, and in those first exciting years of motherhood. Every day we help, inform, and support thousands of (expectant) mothers with our iOS and Android apps, books, website, and social channels.