By the book, baby usually can sleep through the night (six hours or more) without nighttime feedings by six months old. Most parents would like their baby to sleep through the night as that means they could get some sleep, or time to finish the laundry, dishes, cleaning up the house, fixing the bills, the list goes on.
According to the National Sleep Foundation, 70 percents of babies can sleep through the night (eight to 12 hours) by nine months old. There are various of reasons that could contribute to baby not sleeping throughout the night, such as separation anxiety, hunger, illness, increased social skills and motor development. There are no straight rules in getting baby uninterrupted sleep, but establishing an enjoyable bedtime routine will definitely encourage baby to fall asleep independently. You can introduce bedtime routine at four months old.
Taking a warm bath, a milk bottle, reading a bedtime storybook, then bed will signal to your baby that it is time to go to sleep. It will not happen over night therefore parents must be patient and introduce the bedtime routine gradually. Sooner or later your baby's internal clock will start adjusting to this habit.
When babies are put to bed drowsy but not asleep, they are more likely to become "self- soothers" which enables them to fall asleep independently at bedtime and put themselves back to sleep during the night. Those who have become accustomed to parental assistance at bedtime often become "signalers" and cry for their parents to help them return to sleep during the night.
Last but not least, create a sleeping ambience with dark curtains, soothing colour walls, and low dim lights. Ensure the room temperature is right for your baby. Experts recommend the baby's room temperature to be kept between 68-72°F (20–22.2°C).