9-month-old baby: Milestones, development and growth


by Lorna White |

Your 9-month-old baby is really starting to develop their own little personality this month, and you may even begin to hear them say their first little words such as 'mama' or 'dada' which is a super exciting baby milestone for your little one to meet.

Of course, around this age all babies are different and it's normal for them to reach their milestones at different stages. So if your baby isn't being very vocal just yet, it's important not to worry as this could also happen at 10 months old or even beyond that.

As well as their cognitive development coming along, their physical development is going through a very exciting stage and your baby will be crawling very soon so don't forget the baby-proofing this month.

We spoke to Dr Amanda Gummer, a psychologist specialising in child development, play and parenting to find out more about the development milestones and things we should be looking out for at 9 months.

How much should a 9-month-old baby be sleeping?

On average, a 9-month-old baby needs about 12-14 hours of sleep per day, including nighttime sleep and naps. This can vary depending on the individual baby's needs, but most babies in this age group require 2-3 naps per day.

Each nap will typically be around 1-2 hours long, although some babies may take shorter or longer naps.

How much should they be feeding and eating?

At 9 months old, babies may be eating a combination of breast milk or formula milk and solid foods. The specific amount of breast milk or formula a baby needs will depend on their individual needs and appetite, but on average, a 9-month-old baby may consume around 24 to 32 ounces (710 to 950 mL) of breast milk or formula per day, divided into several feedings.

In addition to breast milk or formula, a 9-month-old baby will also typically be eating 3 meals of solid foods per day, along with 1-2 snacks. The amount of solid food a baby needs will vary depending on their appetite and individual needs, but on average, they may be consuming about 2 to 4 tablespoons (30 to 60 mL) of each food per meal.

9-month-old baby cognitive development

At 9 months old, babies experience significant cognitive development. They are becoming increasingly aware of their surroundings and are developing the ability to explore their environment and interact with others. Some key cognitive milestones that are typically reached around this age include:

Problem-solving: Babies are developing problem-solving skills, such as figuring out how to reach for a toy that is just out of reach or how to stack blocks.

Memory for repetitive events: Babies can remember simple events or routines, and get comfort from familiar patterns of events such as the bedtime routine.

Language development: Babies continue to develop their language skills and can understand more words than they can say. Babbling is common at 9 months and baby will soon be talking to you and having little conversations.

Social skills: Babies become more interested in interacting with others and may imitate actions or sounds. They may also show a preference for familiar people and may become upset when separated from their caregivers.

9-month-old baby toys

9-month-old baby physical development

At 9 months old, babies experience significant physical development. They are developing greater control over their movements and are becoming more mobile. Some key physical milestones typically reached at this age include:

Crawling: Many babies start to crawl or scoot on their stomachs or bottoms, although some may skip this stage and move straight to walking.

Pulling up: Babies may start to pull themselves up to a standing position while holding onto furniture or other objects for support.

Fine motor skills: Babies are developing greater control over their hands and fingers, and may be able to pick up small objects, feed themselves finger foods, and bang toys together.

Hand-eye coordination: Babies are learning to coordinate their movements and may be able to throw or roll a ball, or pick up objects with both hands.

Gross motor skills: Babies are becoming more coordinated and baby may soon be able to sit up without support, roll over in both directions, and move from a crawling to a sitting position.

How much should a 9-month-old weigh and measure?

The average weight for a 9-month-old baby is around 18 pounds (8.2 kg) for boys and 16.5 pounds (7.5 kg) for girls.

The average height for a 9-month-old baby is around 28.5 inches (72.4 cm) for boys and 27.5 inches (69.9 cm) for girls.

9-month-old baby health

At 9 months old, there are several health factors that parents should be aware of, including:

Teething: Many babies may be teething around this age, which can cause discomfort, irritability, and changes in eating and sleeping patterns.

Developmental milestones: While every baby develops at their own pace, it's important to monitor your baby's progress and discuss any concerns with your paediatrician. If your baby is not reaching certain milestones, such as sitting up or crawling, it may be a sign of a developmental delay that should be addressed.

Vaccinations: Your baby may be due for vaccinations at this age to protect against serious illnesses such as measles, mumps, and rubella. Talk to your paediatrician about the recommended vaccination schedule for your baby.

Things to think about at 9 months

There are many things that parents can do to aid their 9-month-old baby's development, including:

Encouraging physical activity: Babies at this age are becoming more mobile, so it's important to provide a safe space for them to crawl, stand and explore. This helps strengthen their muscles and develop coordination.

Engaging in interactive play: Playtime is important for a baby's cognitive and social development. Parents can engage in activities such as reading books, singing songs, playing peek-a-boo, and encouraging interactive play with toys.

Providing a stimulating environment: Babies are constantly learning and exploring their environment. Parents can provide a variety of safe and interesting toys, books, and objects to stimulate their baby's senses and encourage exploration.

Promoting healthy sleep habits: Adequate sleep is important for a baby's overall health and development. Parents can establish a consistent bedtime routine, ensure a comfortable sleep environment, and promote healthy sleep habits such as putting their baby to bed while drowsy but awake.

Providing a nutritious diet: At 9 months old, babies are starting to eat more solid foods. Parents can offer a variety of healthy foods to meet their baby's nutritional needs, such as fruits, vegetables, lean protein, and whole grains.

Reading to your baby: Reading to your baby can aid in their cognitive development, language skills, and encourage a love of books and learning. It also promotes bonding between the parent and baby.

About the expert

Dr Amanda Gummer is a psychologist, specialising in child development, play and parenting. Amanda has a PhD in Neuropsychology, the Postgraduate Certificate in Higher Education and over 20 years’ experience working with children and families. She is also the founder of The Good Play Guide.

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