In part 2 of How Bright Light Therapy Helps Seasonal Affective Disorder Kathleen Kendall-Tackett, PhD, IBCLC, FAPA examines the suitability of light therapy for pregnant and postpartum women.
Pregnant and postpartum women may be particularly vulnerable to seasonal affective disorder (SAD). Light therapy has been used with both. According to Crowley and Youngstedt (2012), perinatal women may be particularly vulnerable because of lack of light exposure. Toward the end of pregnancy, their mobility may be restricted, so that they may not spend as much time outside. After the baby is born, they may also spend more time indoors and they may be sleeping more during the day. These changes can desynchronize circadian rhythms, increasing the risk for depression.
An open-label trial with 16 pregnant women with major depression found that there was a 49% improvement in depressive symptoms after three weeks of treatment with bright light (10,000 lux, see part I for “Light intensity, duration and timing of light exposure”). Based on their results, the authors recommended a randomized trial to further test the efficacy of this intervention with depressed pregnant women (Oren et al., 2002).
Bright light therapy was also an intervention in a recent study of mothers with babies in the neonatal intensive care unit (NICU) (Lee, Aycock, & Moloney, 2012). They noted that in addition to the normal stresses associated with having a baby in intensive care, being in the NICU with its low level of light desynchronizes circadian rhythms. With that in mind, they conducted a pilot study with 30 mothers, randomizing 15 mothers to receive 3 weeks of bright light therapy. Seventy-three percent of the mothers were African-American, with a mean age of 26. The light in the NICU was <10 lux bedside, and 100 lux in the lobby. The design called for mothers using a light visor, and the adherence rate was approximately 88%. They found that the mothers in the experimental group had lower levels of depression, and nighttime and morning fatigue, as well as improved physical health-related quality of life. Self-reported sleep quality was better. The authors noted that none of the between-group differences were statistically significant due to the small sample size, but they were clinically significant. Further, the effect sizes ranged from small to large.
Read more in part I about why light therapy is effective and the safety issues of using it to treat seasonal affective disorder.
Crowley, S. K., & Youngstedt, S. D. (2012). Efficacy of light therapy for perinatal depression: A review. Journal of Physiological Anthropology, 31(1), 15. doi:10.1186/1880-6805-31-15
Lee, S.-Y., Aycock, D. M., & Moloney, M. F. (2012). Bright light therapy to promote sleep in mothers of low-birth-weight infants: A pilot study. Biological Research for Nursing, 15(4), 398–406. doi:10.1177/1099800412445612
Oren, D.A., Wisner, K.L., Spinelli, M., Epperson, C.N., Peindl, K.S., Terman, J.S., & Terman, M. (2002). An open trial on morning light therapy for treatment of antenatal depression. American Journal of Psychiatry, 159, 666–669. doi:10.1176/appi.ajp.159.4.666