London - Every new parent knows to expect plenty of sleepless nights with a screaming baby.
But the bad news is that even six years later you will still be missing out on some precious shut-eye.
First-time mothers are deprived of 22 minutes of sleep a night even after their child has started school, a study has found, while fathers lose 14 minutes.
Unfortunately, older children still get up in the night, fall ill and have nightmares. And even when their little ones do sleep soundly, the stresses and strains of parenthood can still make it harder for mum and dad to drop off.
Researchers led by the University of Warwick found that women were far more likely than men to be kept awake by their children. Among more than 4 600 parents, mothers lost more than an hour of sleep per night in the three months after giving birth, while men sacrificed only 13 minutes.
Women were more sleep-deprived right up until their child turned six – believed to be because society still expects them to do more of the household duties and child-rearing.
Dr Sakari Lemola, from the university, said: "We did not expect to see people sleeping less even when their children were six years old. Of course there are childcare demands, and children can become unwell at night. However, it is also likely that there are long-term effects of having children related to increased responsibilities as a parent.
"Before having a child, one is only responsible for oneself and then one becomes responsible for a child and family. While having children is a major source of joy for most parents, it can also bring worries, stress and strains."
The researchers asked 2 541 women and 2,119 men who had children between 2008 and 2015 about their sleep. In the first three months, when babies are at their "peak" for crying, women lost 62 minutes of sleep a night compared to before pregnancy, while men lost 13 minutes on average.
Breastfeeding meant 14 minutes of additional lost sleep for mothers forced to get up for night feeds, but even without this, women still lost more rest than men.
The study, published in the journal Sleep, states that in most industrial countries "mothers, including working women, still have more household and child-rearing responsibilities".
Parents lost out on similar amounts of sleep regardless of age, wealth or whether they own their own home, the study of German parents found.