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3 Months Old Baby

A 3 month old baby is getting bigger and becoming more aware every day.  At this stage the baby should be setting into a schedule. 

At 3 month old the baby is working hard to become more mobile.  The baby now is developing his motor and communications skills.

Physical Development

How much should 3 month-month-old weigh?

In month 3, your baby will start to go from weigh in ounces to pounds. The baby will start gaining around 2 pounds this month and from here on.  The baby can range anywhere from 10.14 – 17.41.

What should the height of a 3-month-old be?

The average height of a 3 month old is any where from 21.96 – 25.70 inches tall.

How much should their head size be?

The head size of a baby should be anywhere between 14.64- 16.81.

What is the respiratory rate of a 3 month old?

The baby’s respiratory rate in 3 months is 30 – 45 breaths per minute.

What is the heart rate of a 3-month-old?

The baby has 90 to 120 beats per minute.

What Should Your Baby Be Doing At 3 Months?

Motor Skills

 The baby motor skill in 3 months is constantly increasingly.  The baby has improved neck strength and can lift his head up. 

 In a short period of time he will be able to start rolling over. 


During 3 months old the baby Moro reflex starts to gradually decrease and go away.


 Your baby now is learning to communicate through facial expressions like frowning or smiling as well as crying, laughing, babbling, and squealing.  During month 3 crying is still his prime mode of expressing himself.

Cognitive Development

At 3 months old, a baby’s cognitive development is increasing exponentially.  In this stage, your baby starts to practice his kicks and reaches as he works on his cognitive development.  He also enjoys looking at himself in the mirror.


The vast majority of babies sprout their first tooth when they’re between 4 and 7 months old.  In this stage, the baby will start showing symptoms of excessive saliva secretion and drooling.

Sensory Development


The baby has increased during the third month. He is able to have more control of his eye muscles.

Hearing Skills

During the third month your baby now is able to recognize the parents voice.  They also start enjoying music during this stage.

How Much Should A 3-Month-Old-Eat?

A baby during the third month should be drinking around 5 ounces of milk.  The baby should be fed around 6 to  8 times  every day.

Sleep Schedule

The baby average sleeping schedule is around 15 hours daily. This includes his night sleep and naps through out the day.

Bowel Movement

In month 3, the baby has regular bowel movements regularly every  other day or multiply times in the same day.


The second dosages of vaccines are given during the third month.  The  different vaccines are DTaP, Hib, IPV, and Meningitis C.

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