Self-reported sleep during the third trimester of pregnancy.

Retrospective (questionnaire) and prospective (5-day diary) self-reports of sleep were obtained from 209 women during the 3rd trimester of pregnancy. On average, the women slept for 465 min, took around 20 min to get to sleep, and were awake for just over 30 min after initial sleep onset having woke 2.6 times on average. Sleep efficiency was around 89%. Significant differences were found between retrospective and prospective reports only on the number of minutes awake after sleep onset and on sleep efficiency. However, these differences were small. Retrospective and prospective reports were only moderately correlated. These results were not markedly different from values reported in much smaller, previous studies of pregnant women using polysomnography, suggesting that the self-reports were valid. The findings suggest that sleep parameters are not as adversely affected during the 3rd trimester of pregnancy as is generally believed.