Despite rumours to the contrary, newborn babies generally like to sleep a lot, on average around 16 hours a day, however this will not necessarily be at night or for long periods and may be punctuated with a fair amount of crying. There really are no hard and fast rules on this, your baby will sleep as long as he/she needs to.
Our own bodies run on a 24-hour clock (known as the circadian rhythm), with a long period of sleep at night. However babies are not born with this and it can take several weeks for them to develop it. By four to six weeks, babies start to develop a more distinct circadian rhythm. Sleep starts to occur in fewer and longer episodes as the baby grows, until the total time spent asleep falls from around 16 hours to about 12 hours by age one.
By six months, most babies are sleeping from 12 to 14 hours a night, mostly in one long block at night with at least one nap taken during the day. It is estimated that most new parents lose at least two hours of sleep for the first four or five months and one hour a night after that. This may not sound much, but it adds up to several hundred lost hours of sleep over the first year of your baby’s life.