A 4-month-old baby can’t sit in a stroller, he can lie flat in the stroller. When the baby is about 8 months old, you can sit on the stroller to take him out.
The spine of babies less than 8 months old is still not enough to support the head, can not sit for a long time, easy to affect the development of the spine, so babies less than 8 months old can lie flat in the stroller when they go out.
When the baby 8 months after the spinal development is gradually perfect, you can take the baby out in the stroller every day, but do not let the baby sit for a long time, this stage of the baby is still mainly lying down.
Note, parents take the baby in the stroller out, be sure to check in advance whether the stroller is safe in all aspects, do not take the baby to the crowded place, to avoid infection with bacteria or viruses.