Developmental milestones are things most children can do by a certain age. Skills such as taking a first step, smiling for the first time, and waving “bye-bye” are called developmental milestones. Children reach milestones in how they play, learn, speak, act, and move. You see children reach milestones every day. Though all children develop at their own pace, most children reach developmental milestones at or about the same age.1

If you want to learn more about this topic, you can watch Rhiannon Joslin's lecture here:

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What should you look out for?

Reaching milestones at the typical ages shows a child is developing as expected. Not reaching milestones or reaching them much later than children the same age can be the earliest indication that a child may have a developmental delay.1 We also have to remember to consider, has a milestone regressed? So was a young person running around, hopping, jumping and then suddenly struggling to get off the floor? If so, that could be an indication of serious pathology, potentially some neurological condition like Duchenne muscular dystrophy or even juvenile idiopathic arthritis.

One more thing to be mindful of, is to consider, have these milestones met, and then regressed or equally, have they been delayed? So have you got a child who hasn’t learned how to sit and they’re a year old and never learned how to sit. These conditions potentially would be something more. It can be something genetic or something from birth history. 2

Regression during puberty 

Regarding periods, which are sort of a late stage marker, what we have to see is, has the girl started the period and they have been regular and then stopped i.e a secondary amenorrhea. 
Or is there no signs of puberty yet and they are over 13 or 15 years of age, in this case it is delayed. In case of regression it can be a chronic disease like Crohn’s or that they’ve got an eating disorder, or it might be something like a Relative energy deficiency syndrome.2

Do not use pain as a marker!

De Martino in 2019, looked at spinal cord malignancy in under three year olds and despite all presentations having a motor regression, all of them, only 59% of them complained of pain. Apart from this, often in juvenile idiopathic arthritis or aspects like that, a child will regress in their motor milestones, but not necessarily complain of pain. Therefore, it’s really important in children not to use pain as the marker.2

The following are some of the common milestones children may reach in the age groups from 5 to 15 year old:

Motor milestones 

5  year olds
Jump rope
Walk backward
Balance on one foot for at least 5 seconds
Use scissors
Begin learning how to tie shoes
Draw a triangle and diamond
Draw a person with six body parts
Know address and phone number
Recognize and recite the alphabet
Write first name
Start to help with chores around the house
Start to lose their baby teeth 2

6-7 year olds
Enjoy many activities and stays busy
Like to paint and draw
Practice skills in order to become better
Jump rope
Ride bikes
Can tie shoelaces
Can do simple math like adding and subtracting 2

8- to 9-year-olds can:
Jump, skip and chase
Dress and groom self completely
Use tools (i.e., hammer, screwdriver) 2

10- to 12-year-olds may:
Like to write, draw and paint 2

Communication milestones

5 year olds
May put together six to eight words into a sentence
May know four or more colors
Knows the days of the week and months
Can name coins and money
Can understand commands with multiple instructions
Talks frequently 2

6- to 7-year-olds:
Cooperate and share
Can get jealous of others and siblings
Like to copy adults
Like to play alone, but friends are becoming important
Play with friends of the same gender
May have occasional temper tantrums
May be modest about body
Like to play board games 2

8- to 9-year-olds:
Like competition and games
Start to mix friends and play with children of different gender
May be modest about body
Enjoy clubs and groups, such as Boy Scouts or Girl Scouts
May become curious about relationships, but does not admit it 2

10- to 12-year-olds:
Will value friendship; may have a best friend
May develop romantic interests
Like and respect parents
Enjoy talking to others 2

Cognitive milestones 

5 year olds
Increased understanding of time
Curious about real facts about the world
May compare rules of parents with that of friend 2

6- to 7-year-olds:

Understand concept of numbers
Know daytime and nighttime
Can differentiate right and left hands
Can copy complex shapes, such as a diamond
Can tell time
Can understand commands with three separate instructions
Can explain objects and their use
Can repeat three numbers backwards
Can read age-appropriate books and/or materials 2

8- to 9-year-olds:
Can count backwards
Know the date
Read more and enjoy reading
Understand fractions
Understand concept of space
Draw and paint
Can name months and days of week, in order
Enjoys collecting objects 2

10- to 12-year-olds
Write stories
Like to write letters
Read well
Enjoy talking on the phone or texting 2

Puberty

Girls
Beginning of puberty: 8 to 13 years
First pubertal change: breast development
Pubic hair development: shortly after breast development
Underarm hair: 12 years old
Menstrual periods: 12 years old on average; normal range is 10 to 15 years old 2

Boys 
Beginning of puberty: 9 to 14 years old
First pubertal change: enlargement of the testicles
Penis enlargement: approximately one year after the testicles begin enlarging
Pubic hair development: 13.5 years old
Nocturnal emissions:  14 years old
Facial and underarm hair, voice changes and acne: 15 years old 2

If you want to learn more about this topic, you can watch Rhiannon Joslin's lecture here:

Click here

Sources:

1. ‘Learn the signs. Act early ‘, Milestones, Center for disease control and prevention, https://www.cdc.gov/ncbddd/actearly/milestones/index.html

2. Retrieved from Growth & development 6 to 12 years, Teenager growth and development 13 to 18 years, Children’s health of orange county (CHOC.org) https://www.choc.org/primary-care/ages-stages/6-to-12-years/

3. ‘Persistent pain in children‘ lecture by Rhiannon Joslin