When a baby's head flops back it can cause the baby's brain to rock inside their head and can bruise the baby's brain or even tear delicate blood vessels.
Shaking a baby can also cause the head to move back and forth quickly and lead to more serious problems.
Shaken baby syndrome can occur when a baby's brain shifts quickly inside their skull and result in tears to the fragile blood vessels.
Symptoms of shaken baby syndrome are irritability, tiredness, breathing problems, loss of consciousness, blindness, motor deficits and even learning disabilities.
It's important to support your baby's head and neck until they can support it themselves.
To support your baby's head and neck you can scoop the baby up with one hand and support their head, neck and spine and tuck your other hand under the baby's bottom for support.
Holding a baby in a sitting position for short periods of time is not bad and is not likely to cause any harm.
However when holding a baby in a sitting position the baby should have good head control and be able to stabilize their bodies.
Propping your baby up in a sitting position and holding them in a sitting position before they are able to stabilize their bodies can put pressure that is harmful on their spine.
If you sit a baby up too early it can interfere with the baby's development and can be dangerous.
Sitting or propping your baby up too early can place harmful pressure on the baby's spine and can lead to spinal cord injury.
Also forcing your baby to sit before their brain has fully developed can lead to and cause brain damage.
sitting your baby too early can also prevent the baby from developing the trunk and head control they require to creep, crawl and sit up safely.
When you sit your baby up too early it can also reduce the amount of time the baby spends on their tummy which is where the baby develops their important reflexes.
Choking is also another possible hazard and risk of propping your baby up to sit too early as the baby can drop their head forward while they feed and choke.
The youngest baby should sit up is 4 months old.
However most babies sit up independently between 6 months to 9 months of age.
At 4 months babies can often hold their head steady without support.
At 6 months babies can sit with some help.
At 9 months babies can sit up well enough without support and can get in and out of a sitting position but may still require some help.
At 12 months babies can get into a sitting position without help.
You can help your baby learn to sit by giving your baby daily tummy time and allowing them to practice sitting while they lean against you.
Babies will begin sitting with support once the baby has good head and neck control, which is usually around 4 to 5 months of age.
And between the ages of 6 and 8 months old, babies will get the hang of sitting independently.
Then by 9 months of age, the baby will be able to get themselves into a sitting position.