Sleeping for two: a cross-sectional study on associations between objectively measured sleep during early to mid-pregnancy and maternal and fetal outcomes and inflammatory biomarker profiles.

Abstract

Background: Pregnant women often experience subjective sleep disturbances shown to be associated with maternal and fetal outcomes. However, subjectively experienced sleep often deviates from objective measurements. Therefore, the aim of this study was to explore the relationship between objectively measured sleep in early to mid-pregnancy and maternal and fetal outcomes and inflammatory biomarkers.

Methodology: A total of 1,610 pregnant women aged 18 or older from the Safe Physical Activity in Pregnancy (SPAP) study were recruited during early (week 10-14) to mid-pregnancy (week 16-19). Blood samples were taken and sleep was monitored using an Actiwatch, tracking total sleep time, sleep efficiency, wake after sleep onset, and sleep onset latency for 7 days in early to mid-pregnancy. A combined sleep categorisation was created using total sleep time and sleep efficiency to categorise participants into three sleep quality groups: Good, Intermediate, and Poor. Maternal and fetal outcomes were collected via questionnaires, medical records, and plasma samples were analysed using the Olink cardiovascular paneI Il (n = 407).

Results: A total of 1,444 participants were included. The women were categorized as good sleepers (50.4%), intermediate (32.6%), or poor sleepers (17.0%) based on the distribution of the participant's sleep parameters. Poor sleep was more common in women born outside Europe, those with higher pre-gestational BMI, and those with pre-pregnancy diabetes. Sleep groups did not differ in metabolic factors. Poor sleep was associated with an increased likelihood of requiring an emergency caesarean section (AOR = 1.86, 95% CI 1.13-3.05). No significant associations were found for other outcomes such as pre-eclampsia, premature birth, small for gestational age etc. Nine inflammatory biomarkers were significantly lower in poor sleepers, while one marker was higher.

Conclusion: Poor sleep in early to mid-pregnancy was more common in pregnant women with pre-pregnancy diabetes, obesity, and those born outside of Europe. Poor sleep was associated with a higher likelihood of emergency caesarean section, but no other maternal or fetal outcomes. An overall trend was observed towards lower levels of inflammatory markers in women that slept poorly; however, additional studies are needed to better understand the immune system's role in the relationship between sleep, maternal health, and maternal and fetal outcomes. Possible mechanisms underlying these associations warrant further research.