MADRID – Poor sleep in early pregnancy might be one significant driver of depression in later pregnancy, an Australian prospective study has found.
"This finding suggests the need for clinicians to not just screen for depressive symptoms during pregnancy (which is the trend now), but to consider other potentially important problems, like the quality of sleep and severe physical symptoms during early pregnancy," Helen Skouteris, Ph.D., said at the World Conference on Women’s Mental Health. "These issues may very well contribute to the development of – or maintain – depression throughout pregnancy."
Dr. Skouteris, an expert in developmental psychology at Deakin University in Burwood, Victoria, presented the results of a prospective study of 257 pregnant women in Australia who were recruited at 15-23 weeks’ gestation. The study consisted of two self-reported questionnaires that assessed physical symptoms of pregnancy, sleep quality, and mood during early pregnancy and during the last trimester.
At recruitment, the women’s mean age was 32 years. Almost half (48%) were first-time mothers and most (77%) were married. Most of the women (73%) also had at least some college education, and 57% had an annual household income of more than 75,000 Australian dollars ($77,500). "This is typical of the women who volunteer for our research programs," Dr. Skouteris noted.
At the time of the first survey, the women had been pregnant for a mean of 18 weeks; the mean gestation at the time of the second survey was 34 weeks.
Both packets, which were mailed to the subjects, contained the self-administered Beck Depression Inventory, the Pittsburgh Sleep Quality Index, and a physical symptoms questionnaire that listed 29 common symptoms of pregnancy. Women were asked to rate these symptoms on a 0-3 scale (with 0 as "not at all" and 3 as "very much") regarding discomfort from the symptoms, their frequency, and their general effect on life. Sleep was reported for the prior 4 weeks, physical symptoms for the prior 8 weeks, and mood at the time of the interview.
A previous study by Dr. Skouteris and her colleagues concluded that physical symptoms were the main driver of maternal depression (J. Affect. Disord. 2010;123:317-20). "In that study, we showed that physical symptoms in early pregnancy were predictive of greater depression scores in late pregnancy," Dr. Skouteris said at the conference. However, that study did not find that sleep quality early on was associated with later physical symptoms, she added.
The current unpublished data, based on three regression analyses, show that poor sleep is the missing link between early physical symptoms and late depression. Fatigue was the most commonly reported physical symptom at both the early and later interviews (94% and 92%, respectively).
"The path seems to travel from severe physical symptoms early to poor sleep throughout, and then to depression later in pregnancy. Clearly, these results show that physical symptoms early in pregnancy might be a key risk factor for depression later on in pregnancy. Now we must consider other moderators in this relationship; there might be other things that contribute to this equation."
She also mentioned that 15% of the women in the study rated very high on the anxiety measure.
"These women were very anxious about the delivery and what it might mean to their education, career, and general way of life," Dr. Skouteris said. "We’re now exploring these subjective ways a woman feels about her pregnancy, and their possible relationship between stress, anxiety, and depression throughout pregnancy and into the postnatal period." This study will provide more data about these links, since the women will be assessed monthly instead of twice.
The Australian Research Council supported the study. Dr. Skouteris had no potential conflicts of interest.