Sleeping patterns during pregnancy in Japanese women.

Although sleep disturbance is commonly reported in pregnancy, there have been few studies on sleep characteristics in pregnancy. In this study, all women attending the antenatal clinic at Sapporo Medical College Hospital for 1 month during autumn and 3 months during winter were surveyed with a questionnaire and sleep log. Of the 192 patients, 169 (88.0%) stated that sleep was altered from their usual experience. A principal components analysis identified three sleep factors from the ten items in the measure of sleep used (Sleep Log). The three factors were: Sleep Duration and Quality, Insomnia and Daytime Alertness. Although no significant differences across trimesters were found on the three sleep factors, Sleep Duration and Quality, and Insomnia were worst during the first trimester. Sleep normalized in the second trimester, but the third trimester was characterized by increased Insomnia and decreased Daytime Alertness. The most frequent reasons cited by women for sleep alterations were urinary frequency, backache or ache in the hips and fetal movement. Contingency X2 analyses were used to investigate a relationship between the frequency of reporting the reasons and the trimester of pregnancy. Significant increases were found in reporting as the reasons for sleep difficulties, fetal movement in the third trimester, and heartburn, nausea and vomiting in the first trimester. The description of sleep patterns during pregnancy has clinical relevance as sleep alterations in pregnancy are common.