The baby seven months still can not sit steadily such as may be normal, if the baby has a calcium deficiency or developmental delay is not normal. There are individual differences between babies, some babies may sit earlier, some sit later, generally around 8~9 months can sit on their own. If your baby is still unsteady at seven months, we suggest that you continue to observe him or her and don’t worry too much. If the baby due to the lack of vitamin D and calcium, make the body calcium amount is insufficient, so that the baby the whole relatively soft, may to seven months still can’t sit steady; there may also be motor function development delay and so on, this time is usually not normal phenomenon. If your baby’s unsteadiness does not improve at seven months, or is accompanied by other symptoms, it is recommended that you go to the hospital in a timely manner.