By Shahed Samadi, MD, MPH
Fellow, University of Arizona Integrative Medicine, Tucson
Dr. Samadi reports no financial relationships relevant to this field of study.
SUMMARY POINTS
- Six randomized controlled trials show that exercise is both a preventive and treatment of depression in pregnancy.
- Aerobic and non-aerobic exercise had similar effects, though only yoga was studied in women who were depressed at baseline.
- The ACOG guideline still holds: ≥ 30 minutes of moderate exercise is beneficial in pregnant women.
SYNOPSIS: Exercise is associated with better mental outcomes during pregnancy.
SOURCE: Daley AJ, et al. The effectiveness of exercise for the prevention and treatment of antenatal depression: Systemic review with meta-analysis. BJOG 2015;122:57-62.
In this meta-analysis, the authors reviewed randomized, controlled trials to determine whether exercise is an effective intervention for preventing and improving depressive symptoms during pregnancy. Study selection included recruitment of non-depressed pregnant women, at risk or diagnosed with antenatal depression and any exercise intervention. Multiple databases were used for data extraction including: Cochrane Database of Systemic Reviews, MEDLINE, Excerpta Medica database, Allied and Complementary Medicine Database, and PsychINFO with published studies dating from 1946 to February 2014. The authors assessed potential studies for their methodological and reporting quality using the Delphi method, a scale used to assess the quality of randomized, controlled trials. The initial electronic database literature search resulted in a total of 919 articles. Of these, six trials met all inclusion criteria. The main reasons for exclusion were any intervention that did not evaluate depression, trials that did not last more than 6 weeks, or any studies that were not randomized, controlled trials.
The six studies were published between 2008 and 2014 in the United States and Colombia and included 406 pregnant women from 16 weeks’ gestation between the ages of 14-38 years. Interventions lasted 8 or 12 weeks, and almost 86% of the participants completed follow up. All trials evaluated exercise as single intervention and used the Centre for Epidemiological Studies-depression scale. Subgroup analyses were performed for women who were not depressed vs those who were depressed or at risk of depression at baseline; the type of exercise intervention was another subgroup analyzed. One trial evaluated aerobic exercise (walking, running, swimming) and five trials evaluated non-aerobic-based exercise (yoga, tai chi, strength training). All of the trials in the analysis of women depressed at baseline evaluated predominately yoga-based activities. All six trials showed a statistically significant reduction in depression scores with exercise (95% confidence interval [CI], -0.87 to -0.05; P = 0.03). The test for subgroup differences in women who were non-depressed and depressed at baseline was not significant (P = 0.32; I2 = 68%). The test for subgroup differences between aerobic and non-aerobic exercise was also not significant (P = 0.32; I2 = 68%). No trials reported data on safety or adverse effects.
COMMENTARY
Major depression is one of the most common mental disorders in the United States, and 6.7% of all U.S. adults have had at least one major depressive episode.1 The burden of depression and other mental health conditions is also on the rise globally, with an estimated 350 million people affected.2 Depression is the third leading contributor to the global disease burden, and is expected to rise to first by 2030.3 Women are commonly subjected to psychiatric illness, particularly during pregnancy, and depression is the most prevailing. Depression has been correlated with negative birth outcomes and it has been shown that children are vulnerable to the long-term effects of maternal depression during pregnancy well into adolescence.4 This is termed intergenerational transmission, which could explain the hereditary risks associated with depression. Researchers have found that children of mothers with a history of depression are five times more likely to have a depressive episode than children of mothers with no history of depression.5 Thus, finding effective interventions is important for the health of the mother and the newborn.
The benefits of exercise are generally positive, as it applies to many clinical conditions. For example, exercise has a protective effect on health and its benefits are long-standing, such as blood pressure reduction, prevention of coronary heart disease, and long-term glycemic control for diabetics, as adaptations to regular exercise improve insulin sensitivity.6 A consistent body of evidence also indicates that depression is associated with dysregulated inflammation and release of pro-inflammatory cytokines, which increase the development of metabolic syndrome.7 The general consensus among the American College of Obstetricians and Gynecologists (ACOG) and the Royal College of Obstetricians and Gynecologists is that exercise is associated with better mental health outcomes during pregnancy. ACOG guidelines suggest that pregnant women without obstetric complications should adopt the same recommendation that was written for non-pregnant women: an accumulation of 30 minutes or more of moderate exercise a day.8 The Centers for Disease Control and Prevention and the American College of Sports Medicine also recommend at least 30 minutes of moderate-intensity physical activity, defined as 3-5 energy metabolic requirements, for nonpregnant women.9 This is equivalent to brisk walking at 3-4 mph.
Exercise may be a safer method of treating depression than antidepressants. Use of antidepressants during pregnancy has been increasing in recent years and is estimated to be at 2-6% among pregnant women.10 Although depression in the general population is approached with both pharmacotherapy and complementary therapies, the disadvantages posed by the use of psychopharmacotherapy are more prominent in pregnant women. Multiple studies have shown an increased risk of pulmonary hypertension11 or other anomalies such as congenital heart defects12 with maternal use of selective serotonin re-uptake inhibitors in pregnancy. In fact, they are listed as FDA pregnancy category C in most sources. Furthermore, antidepressants with serotonergic activity are also known to cause mild to severe sexual dysfunction such as decreased libido, delayed orgasm,13 and even weight gain.14 A potential link between intellect and behavioral issues with antidepressant use during pregnancy also has been studied as a modifiable causal factor.15
Being in a state of depression can be stressful, and vice versa; in these situations, exercise may play a role. For example, stress has been shown to influence increased use of pharmacologic agents, dietary behaviors, and poorer compliance with prenatal care. The intensity, duration, and type of stress can exacerbate depressive symptoms and elevate cortisol levels. Perceived constraints in life, strains in relationships with friends and family, as well as difficulty with finances or job-related demands are some of the most common offending agents. Elevated levels of cortisol can increase one’s risk of developing depression and have the potential to predict adverse birth outcomes. In one study, women with low birth weight infants had higher levels of cortisol.16 Regular exercise has been shown to result in a reduction of circulating cortisol levels. However, studies show that the intensity threshold also matters and has to be taken into consideration. Low-intensity exercise reduces circulating cortisol levels whereas moderate- to high-intensity exercise provoked increases in circulating cortisol levels.17
Expectant mothers could benefit from exercise interventions to improve their physical and mental well being and reduce the risks associated with depression, but this isn’t borne out by results presented here. The findings of this meta-analysis are based on a small sample size and, thus, insufficient power; therefore, discretion is vital when interpreting results. Small demographic covariates and a large age gap between participants make it difficult to generalize to all ethnic populations and age groups. Self-reported race/ethnicity, income, body mass index, other medical conditions, marital status, and region of residence (such as in a metropolitan area) may have affected any potential effect modification on the association between depression and exercise during pregnancy. Although depression scores were reduced with exercise, there was no statistically significant difference between aerobic and non-aerobic exercise. Thus, it is difficult to assert what type of exercise, if any, might be most effective, as there is no clear dominance of one form over another. In addition, only two studies elaborated on whether the exercises were performed during exercise classes or at home. Group interventions provide motivational support from fellow staff and participants and thus make adherence more likely; this may explain the high percentage of participant follow-up in the study. This review does provide some preliminary support about exercise as a possible treatment for antenatal depression. However, a clear-cut conclusion about the use of exercise as a preventive measure for depression cannot be made. More high-quality trials are needed to address this question, and to clarify its safety in this population. In addition, while exercise is a viable alternative to standard medications in the treatment of depression, it would be intriguing to look at the long-term effects on the offspring post-intervention.
REFERENCES
- Major Depression Among Adults. National Institute of Mental Health. (2013). Available at: http://www.nimh.nih.gov/health/statistics/prevalence/major-depression-among-adults.shtml. Accessed Jan. 5, 2016.
- Depression Fact Sheet. World Health Organization. (October 2015). Available at: http://www.who.int/mediacentre/factsheets/fs369/en/. Accessed Jan. 5, 2016.
- Mathers CD, Loncar D. Projections of global mortality and burden of disease from 2002 to 2030. PLoS Med 2006;3:e442.
- Quarini C, et al. Are female children more vulnerable to the long-term effects of maternal depression during pregnancy? J Affect Disord 2016;189:329-335.
- Gotlib IH, et al. Telomere length and cortisol reactivity in children of depressed mothers. Mol Psychiatry 2015;20:615-620.
- Hardman AE. Exercise in the prevention of atherosclerotic, metabolic and hypertensive diseases: A review. J Sports Sci 1996;14:201-218.
- Penninx BW, et al. Understanding the somatic consequences of depression: Biological mechanisms and the role of depression symptom profile. BMC Med 2013;11:129.
- ACOG Committee Obstetric Practice. ACOG Committee opinion. Number 267: Exercise during pregnancy and the postpartum period. Obstet Gynecol 2002;99:171-173.
- Pate RR, et al. A recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA 1995;273:402-407.
- Tran H, Robb AS. SSRI use during pregnancy. Semin Perinatol 2015;39:545-547.
- Huybrechts KF, et al. Antidepressant use late in pregnancy and risk of persistent pulmonary hypertension of the newborn. JAMA 2015;313:2142-2151.
- Wemakor A, et al. Selective serotonin reuptake inhibitor antidepressant use in first trimester pregnancy and risk of specific congenital anomalies: A European register-based study. Eur J Epidemiol 2015;30:1187-1196.
- Montejo AL, et al. Sexual side-effects of antidepressant and antipsychotic drugs. Curr Opin Psychiatry 2015;28:418-423.
- Kloiber S, et al. Clinical risk factors for weight gain during psychopharmacologic treatment of depression: Results from 2 large German observational studies. J Clin Psychiatry 2015;76:e802-e808.
- Rai D, et al. Parental depression, maternal antidepressant use during pregnancy, and risk of autism spectrum disorders: Population based case-control study. BMJ 2013;346:f2059.
- Giurgescu C, et al. Symptoms of depression predict negative birth outcomes in African American women: A pilot study. J Midwifery Womens Health 2015;60:570-577.
- Hill EE, et al. Exercise and circulating cortisol levels: The intensity threshold effect. J Endocrinol Invest 2008;31:587-591.
Exercise is associated with better mental outcomes during pregnancy.
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