[Changes in sleep parameters of young women from late pregnancy to postpartum].

Mothers in postpartum periods are forced to be awake at night in order to take care of their babies. It is important to investigate relationships between the sleep patterns of postpartum mothers and their babies' activities under conditions in daily life to determine effects on their health. In this study, changes in sleep parameters of young women from late pregnancy to the 6th postpartum week were studied using the ambulatory EEG monitoring system. Subjects were 10 primiparae, aged 23-31 yrs (mean age of 26.8 yrs), who had a normal course of pregnancy and delivery. EEG, EMG, EOG and ECG of the mothers and their babies' actigrams from legs during sleep were simultaneously recorded using Medilog 9000 at home at four points: during late pregnancy (36 weeks), and the 1st, 3rd and 6th postpartum weeks. In the late pregnancy period, mean sleep efficiency for the 10 subjects was 94.5%, and mean total sleep time was 368.8 min. We compared the sleep parameters of four points using a two-way analysis of variance (point x subject). Total sleep time showed no significant differences among the four points (postpartum 1st week: 336.8 min, 3rd: 314.2 min, 6th:312.6 min.). Percent of waking time after sleep onset in the 1st postpartum week (21.1%) significantly increased compared with late pregnancy (5.4%), but did not change through the 3rd (19.7%) and 6th week (20.7%). The percent of stage 3 + 4 and stage REM did not change across the four points, but the percent of stage 2 in the postpartum period (1st week: 39.7%, 3rd: 41.2%, 6th: 41.0%) significantly decreased compared with late pregnancy (59.6%). There were no significant differences in the number of awakening among the four points. In conclusion, wakefulness after sleep onset during postpartum period increased compared with late pregnancy. The mothers' sleep pattern did not change through the 1st, 3rd and 6th postpartum weeks. These findings suggested strongly that their sleep was interrupted by their babies' activities, as shown in another abstract.