Survey of maternal sleep practices in late pregnancy in a multi-ethnic sample in South Auckland, New Zealand

Background: The Auckland Stillbirth study demonstrated a two-fold increased risk of late stillbirth for women who did not go to sleep on their left side. Two further studies have confirmed an increased risk of late stillbirth with supine sleep position. As sleep position is modifiable, we surveyed self-reported late pregnancy sleep position, knowledge about sleep position, and views about changing going-to-sleep position.

Methods: Participants in this 2014 survey were pregnant women (n = 377) in their third trimester from South Auckland, New Zealand, a multi-ethnic and predominantly low socio-economic population. An ethnically-representative sample was obtained using random sampling. Multivariable logistic regression was performed to identify factors independently associated with non-left sided going-to-sleep position in late pregnancy.

Results: Respondents were 28 to 42 weeks' gestation. Reported going-to-sleep position in the last week was left side (30%), right side (22%), supine (3%), either side (39%) and other (6%). Two thirds (68%) reported they had received advice about sleep position. Non-left sleepers were asked if they would be able to change to their left side if it was better for their baby; 87% reported they would have little or no difficulty changing. Women who reported a non-left going-to-sleep position were more likely to be of Maori (aOR 2.64 95% CI 1.23-5.66) or Pacific (aOR 2.91 95% CI 1.46-5.78) ethnicity; had a lower body mass index (BMI) (aOR 0.93 95% CI 0.89-0.96); and were less likely to sleep on the left-hand side of the bed (aOR 3.29 95% CI 2.03-5.32).

Conclusions: Maternal going-to-sleep position in the last week was side-lying in 91% of participants. The majority had received advice to sleep on their side or avoid supine sleep position. Sleeping on the left-hand side of the bed was associated with going-to-sleep on the left side. Most non-left sleepers reported their sleeping position could be modified to the left side suggesting a public health intervention about sleep position is likely to be feasible in other multi-ethnic communities.