Postpartum depression impacts the lives of 10-15% of postpartum women and typically occurs within one month of giving birth, despite the identification of some clear risk factors1,2. Furthermore, having a baby is often viewed as a joyous event and there is a negative stigma associated with depression that occurs following the birth. Research has indicated that there are risk factors that can strongly predict postpartum depression, such as socioeconomic status, relationship status, and mental health throughout pregnancy but less research has focused on nutritional factors influencing postpartum depression2,3.
Being able to make adjustments in the diet during pregnancy to reduce the risk of postpartum depression could increase a mother’s ability to bond with her baby, make social interactions and increase positive outcomes for her baby. Despite the prevalence of postpartum depression, risk factors that help to predict postpartum depression are not always clear, and postpartum depression may not be discussed with women, regardless of their risk status. Parker et al. , HoggKollars et al. , and Etebary et al. all discuss different nutritional factors that may affect the development of postpartum depression 1,3,4.
Looking at the association between micronutrients and essential fatty acids and postpartum depression could help women in the antenatal period refine their diet and supplement intake to best prevent the negative repercussions that accompany postpartum depression. When the role of nutrients is not adequately assessed, it presents a problem because the onset of postpartum depression can have significant impact, not only on the mother, but on her infant – bonding, cognitive development and child behavior.
5,6 A oman needs the tools to predict postpartum depression so that she may reduce the risk and, therefore, increase her risk of experiencing postpartum depression. Screening for postpartum depression is important, but predicting it may be more useful. Predicting postpartum depression can include screening for depression in the perinatal period. It is unclear if it is more important to identify postpartum depression once it has presented, or if assessing and identifying an at-risk patient in the antenatal period will improve treatment.
Gjerdingen and Yawn suggested that research indicates predicting postpartum depression with a screening test is not well supported and may not have significant improvement when compared to postpartum screening2. The purpose of this literature review is to determine which nutritional factors: essential fatty acids, iron, copper, zinc, magnesium or selenium, are predictors of postpartum depression and what may be missing in the analysis of postpartum depression prediction 1,3,4,7-9.
The analysis will discuss the results of studies assessing nutrition and postpartum depression, and the methodology employed in the various studies. As a mother of two, I have experienced the postpartum “baby blues” which is sometimes confused with postpartum depression. After a particularly stressful birth of my second son I told to “get it together because [l] should be happy to have a baby” by a labor and delivery provider and I realized there is a grave need for all healthcare providers to be more aware of what postpartum depression is and how to help women who have it or are at risk for it.
To research the topic of nutritional factors and postpartum depression, all subject populations in studies will be women who are in the antenatal period or reflect on that period and the are assessed again in the postpartum period. When selecting articles, I will mostly look at studies that looked for nutritional predictors of postpartum depression in women who were pregnant at the beginning of their enrollment of the study and were no more than twelve months postpartum at the final intervention or ssessment, or studies that are retrospective for that period of time.
The only exception to this will be completely retrospective research where the woman many recall from the antenatal period. I picked this time period during pregnancy and twelve months afterwards because to observe a change, researchers need to have a baseline during pregnancy and determine if there is a change in depression level afterwards. Furthermore, postpartum depression has usually had its onset within the first year4.
By limiting my selection to this population, I will be excluding men who get depression during the postpartum period, women who may get postpartum depression after a year has gone by and perhaps women who have miscarriages during their pregnancy. When looking for articles that investigate the effect of nutrition on postpartum depression, have looked for the studies that are peered reviewed and have been published in the last 8 to 10 years.
The studies, so far, have used retrospective and prospective data collection methods to look at the effects of nutrition on postpartum depression. In retrospective studies, the subjects were asked to recall dietary habits and recall emotions felt in the months following pregnancy1,3,4. Others used food frequency questionnaires to assess habitual intake during pregnancy, both from a retrospective stance and for prospective research1,3. Still others assessed dietary status through blood samples1,3,7-9.
To assess postpartum depression, a variety of tools were utilized: the Edinburgh Postnatal Depression Scale, the MINI, Patient Health Questionnaire or the Postpartum Depression Screening Scale 1,3,4,7-9. For prospective studies, these scales were often utilized during the antenatal period as well as the postpartum period to assess change in depression status1,3 4. While assessing the impact of nutritional factors on postpartum depression the methods of analysis varied.
The variables were analyzed frequently by mean comparison – average concentration of a nutrient at a specific time or score on a test and again on follow up. However, in general the analyses performed, to assess nutritional factors and postpartum depression, were multivariate logistic regression and univariate logistic, independent t-test analyses, Pearson’s r correlation and ANOVA tests 1,3,4,7-10. In a t-test two independent means are compared – as stated above, this form of analysis is common.
An ANOVA compares three means to determine if any significant difference occurs between any of the three groups/means. In a Pearson’s r test, two independent variables are significantly correlated to one another or not. If they are significantly correlated, it may imply that one can predict the other. A multivariate logistic regression has many predictor (independent) variable and associate them with one dependent variable. A univariate regression analysis looks at a single predictor and dependent variable – may be conducted before a multivariate analysis.
The exclusion criteria, when looking at articles, will be to omit any that look at major depression disorder, or depressive mood instead of postpartum depression. Postpartum depression is a separate condition from major depression and is specific to women and to a specific period of time2,5,6. It is essential that the articles address and analyze data regarding postpartum depression as opposed to generalized major depressive disorder. Also, data will only be included if it looks at women from the antenatal period or just after birth, to the onset of postpartum depression up to a year from birth.
This time period is set because postpartum depression typically sets in within a few weeks of birth to up to a year, with the majority of cases occurring by 6 months1,2,5,6. Socioeconomic status, health, age, education, income, previous mental illness have been widely studied in relation to postpartum depression but this literature review is concentrating on nutritional factors and, therefore, these factors will be excluded in the article criteria.
Nutritional factors analyzed in the articles that will be included in the literature review will be essential fatty acids, iron, selenium, calcium, zinc and magnesium. The articles will allow the literature to truly reflect current research on nutritional factors that can be altered by women to help prevent postpartum depression during the antenatal period and prevent it during the postpartum period as well.
By selecting and omitting articles, based on this criteria, it is possible that articles that illustrate strong associations between a nutrient and the prevention of or contribution to depression may be missed. It is also possible that the time period selected may not capture the entire period in which postpartum depression may develop. The criteria forth, for inclusion and exclusion of selected articles, will allow the question “do certain nutritional factors influence the development of postpartum depression” to be answered.