[An epidemiological study of sleep problems among the Japanese pregnant women]

The objective of the study was to identify: 1) what kinds of sleep problems that pregnant women experience in Japan; and 2) the relationships between sleep problems and month of pregnancy, sleep problems and the number of pregnancies, and sleeping hours, by means of a questionnaire given to pregnant women in Japan. Conditions to assure good quality sleep were studied.

Of 500 obstetric facilities which were randomly selected from areas surveyed by the Japan Association of Obstetricians and Gynecologists, 260 finally agreed to participate in this study. Women who had their pregnancy confirmed and were on a revisit to the 260 obstetric facilities were enrolled. These pregnant women completed anonymous self-administered questionnaires during the waiting time for treatment and submitted them to the obstetric facilities in sealed envelopes. The questionnaire covered personal attributes such as age and highest level of education, pregnancy status, working status, and patterns of smoking and alcohol drinking. Sleep-related items such as 1) subjective sleep quality, 2) difficulty in getting to sleep, 3) frequent awakenings, 4) waking up too early, 5) sleeping hours and 6) daytime drowsiness were also included.

The month of pregnancy was significantly related to four sleep-related items, including difficulty in getting to sleep and waking up too early. With respect to the relationship between the number of pregnancies and sleep problems, significance was found for five sleep-related items, including subjective sleep quality and waking up too early. Poor subjective sleep quality was significantly related to sleeping less than seven hours and whether or not pregnant women had a regular job. It was also suggested that the greater the number of pregnancies, the shorter the sleeping hours. When responses to each sleep-related item were compared between pregnant women and the general population, the former were more likely to have sleep problems.

These findings suggest that as well as the number of pregnancies and month of pregnancy with sleeping hours may be factor intimately related to sleep problems during pregnancy. A good quality sleep during pregnancy is vital for normal maternal health and fetal growth and sufficient sleeping hours are therefore needed. Attention should therefore be paid to the finding that pregnant women were more likely to have sleep problems than the general population.