First year milestones: Baby milestones by month

Understanding newborn, infant, and toddler age ranges

Different terms are often used interchangeably to describe babies and young children. Before we explore developmental milestones, let’s clarify what we mean by newborn, infant, and toddler.

What is the newborn phase?

According to the World Health Organization (WHO), the newborn phase begins once the baby is born and lasts for the first 28 days of life. Some believe that the newborn phase starts once the baby is born through the first 8 weeks. Many medical experts consider the newborn stage to be the baby’s first 12 weeks of life.

Premature

Babies born early are considered premature because they are born prior to 37th week of pregnancy. Babies are born early for several reasons including diabetes, high blood pressure, or genetics.

What is the infant age range?

A baby is an infant through their first year of life, from birth to 1 year. There is overlap between the terms “newborn” and “infant” since infancy includes the newborn phase.During the first three months of a baby’s life, the terms “newborn” and “infant” can be used to describe a baby, and you might even hear the term “newborn infant.”

What is the toddler age range?

After infancy, a child becomes a toddler. A child enters toddlerhood once they reach their first birthday. Children are considered toddlers from their first birthday until age three.

What is the difference between a toddler and a preschooler?

From ages 3 to 5, children are considered preschoolers. During this stage, while kids are still growing physically, much of their energy is focused on mental and emotional development. Many kids begin school at this age, which is why it’s called the preschool stage.

Newborn baby milestones, week by week

Caring for a newborn is a learning curve for new parents. At this stage, your baby is adjusting to life outside the womb, and both of you are getting to know each other. With everything feeling new, it can easily become overwhelming. Before diving into milestones, it’s helpful to first understand the two main activities that fill a newborn’s day: sleep and feeding.

Newborn sleep

Newborns sleep a lot in a 24-hour period, with about 16 to 17 hours of sleep in a 24-hour period.

Newborns have small stomachs so they will wake up every 3 to 4 hours to eat.  

Newborn eating habits

In a 24-hour period, most newborns will have 16 to 24 oz of milk, whether breast milk, formula, or a combination of the two. Breastfed babies feed more frequently, typically 8 to 12 times a day, also known as cluster feeding. The general guideline is to feed newborns on demand, letting them eat as much as they need. Tracking wet and dirty diapers is a good way to ensure they’re getting enough to eat. At each checkup, your pediatrician will ask about your baby’s progress with developmental milestones—a process called developmental monitoring.

Newborn developmental milestones: Week-by-week

Week 1

During the first week, your baby will spend most of their time sleeping. In their brief awake periods, they may open their eyes or lift their head momentarily. You’ll also start to notice natural reflexes, like the startle (Moro) reflex, rooting reflex, and sucking reflex.

Your baby will still have their umbilical cord stump, so it’s essential to keep it clean. Watch for signs of jaundice, feed frequently to help them regain the weight lost in the first few days, and track wet and dirty diapers to make sure they’re getting enough to eat.

Week 2

By the second week, most babies have regained their birth weight. Formula-fed babies typically regain weight a bit faster than breastfed babies. If you’re breastfeeding, it might take a little more time to establish a routine, so breastfed babies may take slightly longer to get back to their birth weight. Regardless of feeding method, most newborns experience an increase in appetite during this week.

Week 3

Even if your little one isn't sleeping for long stretches yet, it's important to start working on a nighttime or sleep routine. This will help establish a rhythm of eating, sleeping, and diaper changes, making it easier to incorporate activities like tummy time and play during wake windows. During these wake periods, engage your child with songs, reading books, or making silly faces can provide beneficial stimulation.

Week 4

Keep practicing tummy time, even if your baby doesn’t enjoy it. Just a minute or two each day can be beneficial. If your baby’s weight is looking good, your pediatrician may no longer suggest counting diapers. At this stage, your baby may begin to experiment with their voice and produce amusing sounds. Engage with your baby by "talking back" during these moments to support their development.

Week 5

Newborns will start to string together longer stretches of sleep time. Even if you’re having sleep struggles, creating a sleep routine can help establish healthy sleep habits for the future.

Your baby has the stamina for longer stretches of tummy time and will look around in more directions and focus on objects of different patterns and colors.

Week 6

Your baby will continue to eat 24 to 32 ounces per day, but may eat less often. Instead of every 2 to 3 hours, you can extend the time between feedings to 3 to 4 hours.

Week 7

As your baby approaches the 2 month mark, they are likely looking very much like a baby and less like a newborn. It probably helps that they’re likely practicing using their voice more often and hopefully enjoying tummy time more. Don’t forget to continue helping your baby practice those skills which are super important for their physical growth and development.

Week 8

Your baby will begin to closely examine faces, calm down when they hear your voice, and may smile in response. They’ll show increased interest in their toys and observe the people around them as they move. During tummy time, most 8-week-olds can lift their heads and lose the startle reflex. As they gain weight, your baby will transition from one diaper size to the next.

How can I help my newborn meet their newborn milestones?

• Provide a loving environment
• Ensure proper nutrition
• Tummy time
• Stimulate their senses with different textures, colors, and voices
• Establish routines
• Encourage social growth
• Monitor development milestones
• Attend pediatrician appointments

If you ever have concerns about whether your baby is meeting milestones, don’t hesitate to discuss them with your pediatrician. Consult your local or Summer Health pediatrician for additional guidance.  

First year: Major infant developmental milestones by month

Infant sleep

The American Academy of Sleep Medicine (AASM) recommends that infants aged 4 to 12 months get 12 to 16 hours of sleep within a 24-hour period. As with the newborn phase, this total sleep time includes naps. Once your baby reaches the infant stage, they may begin to establish a more predictable sleep schedule that incorporates both nap time and nighttime sleep.

Infant eating habits

Babies start eating solids between 4 and 6 months, leading to significant changes in their eating habits and meal routines.

Four-month milestones

• Smile spontaneously
• Chuckle or coo to gain your attention
• Respond to your voice by making sounds back or turning their head to look at you
• Babbling
• Show improved ability to hold toys in their hands
• Hold their heads steady when being held

Six-month milestones

• Recognize loved-ones
• Recognize themselves in the mirror
• Laughing
• Babbling and high-pitched squealing noises
• Grabbing
• Putting toys in their mouth
• Rolling over from tummy to back

Nine-month milestones

• Stranger anxiety
• Separation anxiety
• Recognize and respond to their own name
• Stringing sounds together
• Sit without support
• Get into the sitting position on their own
• Say “dada”

Twelve-month milestones

• Wave
• Say “mama” and “dada”
• Put objects in containers
• Pull to stand
• First steps
• Pick up small objects using their index finger and thumb

Developmental screenings during infancy

Your baby will have their first developmental and behavioral screening at 9 months. Developmental screenings are more formal than standard developmental monitoring of milestones. During developmental screening and behavioral screening, your child’s pediatrician will use questionnaires to assess how well your child is developing in areas like language, behavior, emotions, and movement.

A look ahead: Toddler age range and toddler milestones

Your baby’s transition from infant to toddler

Toddlers are naturally curious and actively practicing new skills. While newborns and infants may experience rapid transitions, the shift from infant to toddler can be particularly challenging for parents. Some may feel like they’ve just figured out how to care for a baby, only to realize their child now has different needs. This transition can also be emotional for many parents as they witness clear signs of their child growing up!

Major transitions happening during the transition from infant to toddler include:

• First steps: By 15 months, most toddlers have taken their first steps and others are comfortably walking.
• Eating: After age 1, toddlers are getting most of their nutrients from solid foods, along with some type of milk source.
• Dropping naps: Toddlers need slightly less sleep than infants. Toddlers between age one and two should get 11 to 14 hours of sleep in a 24-hour period, including naps.

Developmental screenings for toddlers

During the toddler years, your child will undergo two additional developmental screenings, one at 18 months and another at 30 months. Additionally, toddlers should receive autism screenings at 18 and 24 months, which includes a questionnaire about your child. While understanding developmental milestones is important, it’s essential to remember that each child is unique, and every child progresses differently.  

If you have additional questions about your child’s developmental progress, consult your local or Summer Health pediatrician for support.