Perinatal sleep and postnatal mood in New Zealand women : an investigation of the relationship and trial of a sleep education intervention : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Public Health at Massey University, Sleep/wake Research Centre, Wellington campus, New Zealand

Abstract

Changes to normal sleep are experienced by almost all women in pregnancy and the postnatal period. Little is known about the frequency, magnitude or chronicity of these changes, or the relationship between perinatal sleep and postnatal mood. Two studies were completed to investigate these relationships and to trial a sleep education intervention. Study One involved 316 Māori and 635 non-Māori women. Women completed sleep and health surveys during the third trimester of pregnancy, at 4-6 weeks and 12 weeks postpartum. On average, sleep duration and quality were highest before pregnancy, lowest in late pregnancy and did not return to usual, non-pregnant levels by 3 months postpartum. Symptoms of minor and major depression, measured using the Edinburgh Postnatal Depression Scale, were more common in pregnancy (35.6% minor, 16.5% major depression) than at 3 months postpartum (16.3% minor, 7.8% major depression). Hierarchical regression models were used to investigate the relationship between sleep and postnatal mood. After controlling for demographics and known risk factors, both sleep quality and quantity were related to postnatal depression, especially when sleep continued to decline after birth and the magnitude of sleep change was large. Difficulty falling asleep, staying asleep, and restless legs syndrome were all also related to postnatal depression. Study Two was a controlled trial of a behavioural-educational sleep intervention for first-time mothers. Control group mothers (n=20) attended a prenatal, general information session and received two contact-only telephone calls at 2 and 4 weeks postpartum. Intervention group mothers, (n=20) attended a prenatal sleep education session and received weekly support calls in the first 6 weeks postpartum. All mothers completed sleep and health questionnaires. Sleep was objectively measured in all mother-infant pairs at 6 and 12 weeks postpartum using actigraphy. Intervention group mothers experienced a greater increase in sleep at night than control mothers, and reported higher levels of confidence, but no other group differences were found. Replication of the intervention and extension of the study timeframe are recommended. These findings indicate the importance of sleep for maternal health and have implications for the practice of health professionals and maternal health policy.