Sleep-wake cycles, social rhythms, and sleeping arrangement during Japanese childbearing family transition.

Objective: To examine how sleep-wake cycles and social rhythms of Japanese parents are related to their sleeping arrangements before and after the birth of their first child.

Design: Prospective longitudinal, time-series methods.

Setting: Participants' homes in four geographical areas of Japan.

Participants: Convenience sample of 101 Japanese first-time parent couples who completed antepartum and postpartum questionnaires.

Main Outcome Measures: 24-hr sleep-wake rhythm from 7-day logs at 32 to 36 weeks gestation and 4 to 5 weeks postpartum and daily social rhythm from Monk's Social Rhythm Metric.

Results: Mothers' total sleep time and activity level decreased after birth. Social rhythms became less regular for mothers and more consistent and regular for fathers. Although sleeping arrangement had no effect on parents' daily social rhythms, it had a significant effect on the 24-hr sleep-wake rhythm. Regularity of sleep-wake rhythms was more prominent for fathers sleeping with mother and baby than for fathers sleeping alone.

Conclusions: Couples having their first child face great changes in their sleep-wake cycles and social rhythms. Nurses can counsel expectant parents to think about their sleeping habits and social activities and assist them in making informed decisions about the best sleeping arrangement during transition to parenthood.