Postpartum depression (PPD) could lead to poor sleep quality, says a new study, which claims that depression symptoms worsen in PPD patients when their quality of sleep declines.

Sleep deprivation can hamper a mother's ability to care for her infant, as judgment and concentration decline. In fact, sleep-deprived mothers may unintentionally compromise their infants' sleep quality because infants often adopt their mothers' circadian sleep rhythms.

Following childbirth all new mothers experience some sleep loss, as their estrogen and progesterone hormone levels plunge. They typically spend 20 percent more of the day awake than average during the first six weeks postpartum.

Postpartum women wake more frequently and have less dream sleep than non-postpartum women, with women in their first month postpartum spending only 81 percent of their time in bed actually sleeping.

Also, neurotransmitters that influence sleep quality affect mood and raises sleep-deprived mothers' risk for depression.

Almost 6.5 to 13 percent of new mothers suffer from PPD in the United States, with there being more than 4.2 million births per year. And the rate is nearly 50 percent among mothers in the lowest socioeconomic levels.For the research, study author Bobbie Posmontier of Drexel University compared sleep patterns of 46 postpartum women, half with symptoms of PPD and half without. Sleep patterns were monitored for seven consecutive days.

The findings revealed that mothers suffering from PPD took longer to fall asleep and slept for shorter periods. The worse their sleep quality, the worse their depression.