Alterations in sleep during pregnancy and postpartum: a review of 30 years of research.

Pregnancy, childbirth, and early motherhood physiologically and psychologically affect a woman's sleep. Hormonal alterations during early pregnancy, enlargement of the fetus during late pregnancy, and a newborn with random sleep-wake patterns all contribute to disrupted sleep. Since the initial study of sleep and pregnancy in 1968, fewer than 20 articles have been published which address alterations in sleep architecture related specifically to childbearing women. Furthermore, many of these studies suffer from small sample sizes and lack statistical power for consistent interpretation and replication of findings. While almost all of these studies included both nulliparas and multiparas in their samples, rarely have effects of parity been reported. The majority of older studies were cross-sectional designs, with comparisons to age-matched healthy controls. More recent studies have been longitudinal designs to describe changes in sleep during the course of pregnancy. However, women's baseline, prepregnancy sleep patterns or sleep histories have not been considered. With very few published reports of sleep changes related to mental health outcomes, we are no closer to understanding the implications of altered sleep patterns on postpartum depression or other women's health outcomes than we were when it was originally questioned 30 years ago.