Profound lifestyle changes that are brought about by caring for the infant are also frequently hypothesized to cause PPD. However, little evidence supports this hypothesis. Mothers who have had several previous children without suffering PPD can nonetheless suffer it with their latest child. Despite the biological and psychosocial changes that may accompany pregnancy and the postpartum period, most women are not diagnosed with PPD. Many mothers are unable to get the rest they need to fully recover from giving birth. Sleep deprivation can lead to physical discomfort and exhaustion, which can contribute to the symptoms of postpartum depression.