Is low vitamin D during pregnancy predictive of postpartum depression?
Public Health Nutrition Editorial Highlight ‘Association of antepartum vitamin D deficiency with postpartum depression: a clinical perspective’ Author Mercedes J Szpunar discusses their research below.
Postpartum depression (PPD) affects up to 20% of women within the first 12 months after delivery of a newborn. PPD is a debilitating disorder that negatively impacts the entire family unit because a new mother may experience feelings of being overwhelmed, mood changes, irritability, poor sleep and guilt. These feelings may impair her care of the newborn, and additionally, may have deleterious consequences for the development of the child, such as poor growth, impaired attachment, decreased cognitive ability, and dysregulated attention and emotions.
Vitamin D is a fat-soluble vitamin produced in the skin after exposure to sunlight, but it has limited availability from dietary sources. The importance of vitamin D in physical health – including skeletal and endocrine processes – is well established. Increasing evidence also indicates the importance of vitamin D in mental health, specifically in mood. Furthermore, fertility and reproductive functioning may be compromised in the setting of vitamin D deficiency. A number of studies have found low normal or inadequate blood levels of vitamin D in pregnant women, including in locations with high sun exposure. Recent data suggests that vitamin D deficiency early in pregnancy is associated with increased depressive symptoms later in pregnancy.
The purpose of this literature investigation [link to my PHN article] was to determine if vitamin D deficiency during pregnancy was associated with postpartum depression. If this hypothesis is correct, intervention during pregnancy – i.e., vitamin D supplementation – could potentially prevent this debilitating disorder in the postpartum period. Four out of five prospective studies discovered an inverse relationship with a pregnant women’s blood level of vitamin D and depressive symptoms postpartum, or that vitamin D supplementation during pregnancy decreased postpartum depressive symptoms. This finding implies that low vitamin D during pregnancy and postpartum depression are related, but a causative mechanism remains to be determined.
The Endocrine Society recommends routine vitamin D supplementation during pregnancy and lactation due to increased metabolic demand in the mother, but a recent Cochrane Review recommended against this practice. Anecdotally, this author routinely evaluates vitamin D blood levels in patients assessed for PPD, and the result is often low normal or deficient. Oral vitamin D supplementation is considered a safe and cost-effective intervention during pregnancy, with few known adverse effects.
While the benefit of vitamin D supplementation during pregnancy as preventative for depression requires additional investigation, its supplementation has known benefit in reducing pregnancy complications, such as preeclampsia, gestational diabetes, and preterm delivery. Thus, screening pregnant women for blood levels of vitamin D should be a public health priority, and if a deficiency is revealed, supplementation should be recommended by the woman’s provider. This practice may reduce the incidence of postpartum depression, but further research is required to confirm this theory.
The full article ‘Association of antepartum vitamin D deficiency with postpartum depression: a clinical perspective’ published in Public Health Nutrition is available to download for free for a limited time.