Researchers at the University of Michigan have found that babies whose mothers experienced depression any time before they became pregnant, or developed mood problems while they were pregnant, are much more prone to having chaotic sleep patterns in the first half-year of life than babies born to non-depressed moms.

They explained their finding by giving an example - infants born to depressed moms sleep more during the day, take much longer to settle down to sleep at night, and wake up more often during the night.

The researchers said that not only does this add to parents' sleepless nights, but also it may help set these children up for their own depression later in life.

Roseanne Armitage, Ph.D., the leader of the U-M Sleep and Chronophysiology Laboratory team at the U-M Depression Center, however, said that this doesn't mean that babies born to depressed moms are doomed to follow in their mothers' shoes, even though depression does tend to run in families.

Nor does it mean that parents who haven't suffered depression can ignore the importance of their babies' sleep.

Instead, it means that all parents - especially ones with a history of depression - must pay close attention to the conditions they create for their infant's sleep, from birth, she added.

"Keeping a very regular sleep schedule is incredibly important. We know that for both children and adults, and from this study we now know that for infants, the more stable the bedtime the less chaotic sleep is during the night," said Armitage.