Cross-Cultural Differences in Maternal Insomnia and Infant Sleep Patterns

Mothers in Korea experience higher levels of insomnia compared with those in the United States and Australia, and their infants have shorter nighttime sleep and longer sleep onset latency, according to study findings published in Behavioral Sleep Medicine.

Researchers analyzed data from the US, Australia, and Korea to compare infant sleep patterns, parental insomnia, and the effect of sleep location on both parent and infant sleep outcomes. They used the Brief Infant Sleep Questionnaire to measure infant sleep patterns, behaviors, environment, and location, as well as total nighttime sleep time, sleep onset latency, and co-sleeping. The Dysfunctional Beliefs and Attitudes about Sleep Scale was used to measure beliefs and attitudes about sleep, while the Insomnia Severity Index was used to assess difficulties with falling and staying asleep.

A total of 2005 infants and 2005 mothers were included in the study. The mean (SD) age of the infants was 13.82 (6.23) months. Among the mothers, 51.1% were aged between 29 and 34 years, and 72.1% were Caucasian.

Compared with mothers in the US and Australia, Korean mothers had higher total Insomnia Severity Index scores and higher mean Dysfunctional Beliefs and Attitudes about Sleep scores at all timepoints (P <.001 and P ≤.04, respectively). Their infants also had shorter mean nighttime sleep time by 4.2 to 75.6 minutes, and longer mean sleep onset latency by 2.16 to 19.17 minutes, than those in the other countries.

Infants of American mothers consistently slept longer at night compared with infants of Korean mothers, with differences ranging from 34.2 to 66.0 minutes across all timepoints (P <.05). Similarly, infants of Australian mothers slept significantly longer at 12 and 24 months by 83.4 minutes and by 53.4 minutes, respectively (P <.002).

In terms of sleep onset latency, infants of American mothers fell asleep faster than Korean infants at all timepoints, with differences ranging from 11.86 to 17.73 minutes (P <.05). Australian infants also showed significantly shorter sleep onset latencies at 12 and 24 months by 14.28 and 14.06 minutes, respectively (P <.01).

At 24 months postpartum, American infants had significantly longer daytime sleep than Korean infants, with a difference of 12.0 minutes (P =.004).

Researchers noted co-sleeping rates at 6, 12, and 24 months: 54%, 31%, and 20% among Australian participants; 77%, 85%, and 77% among Korean participants; and 13%, 6%, and 5% among American participants, respectively. At 12 and 24 months, Korean participants were 2.80 and 2.31 times more likely to co-sleep at 12 and 24 months than Australian participants (P <.001).

There was a significant association between co-sleeping and infant sleep onset latency (38.55; P =.004) and daytime total sleep time (0.86; P =.046) at 6 months postpartum. After adjusting for nonsignificant interactions, co-sleeping was significantly associated with shorter infant nighttime total sleep time at all timepoints (P <.031), but not infant nighttime awakenings. In addition, bedsharing was found to lower Insomnia Severity Index scores for Korean mothers at 24 months postpartum (P =.043).

Study limitations include inconsistent methods for measuring data, lack of generalizability to individuals in other countries, and subjective infant sleep reports.

The researchers concluded, “[C]o-sleeping and bedsharing are prominent cultural practices with measurable effects…contextual factors such as parental insomnia, knowledge about behavioral sleep interventions and practices, gender roles in caregiving, and architectural constraints also play significant roles.”