If your baby isn’t sitting on their own by age nine months, contact your pediatrician. It may be good to act sooner, especially if your baby is close to 9 months and is unable to sit with support. Development varies from baby to baby, but this may be a sign of a gross motor skill delay.

Babies do reach milestones at different times.

I believe babies begin sitting up unaided at about six months. If you’re concerned speak with your GP or community health nurse.

Most children start sitting somewhere between 4 and 7 months, but every child follows it’s own cue. There are some things you can do to help your child sit up. Have for example a look here (many other websites with info out there) http://day2dayparenting.com/help-baby-sit-up-independently/