They looked at data of patients who visited the Women’s Health Concerns Clinic in Hamilton (WCHH), Ontario, in the period between 2009 and 2016.
“During this time, the WHCC was the principal setting in southwestern Ontario specializing in treating mood and anxiety disorders during the perinatal period,” the researchers wrote in their report, published this month in the Journal of Obstetrics and Gynaecology Canada.
Because of this, the researchers said the results may not be generalizable to all pregnant women, but added that “regardless, clinicians providing antenatal care may benefit from an awareness of the possible role of iron deficiency in the development and risk of maternal depression during pregnancy.”
Study design and results
The retrospective study, which means the researchers looked at past data of patients, included data of women between the ages of 18 and 25 who were in middle to late pregnancy when they completed the Edinburgh Postnatal Depression Scale (EPDS) questionnaire at the clinic.
They also had to have had blood drawn for the analysis of serum ferritin, a biological marker of iron storage, the same day they filled the EPDS questionnaire. Overall, 142 women met this criteria.
Compiled data revealed that 31% of women were iron deficient. On average, iron deficient pregnant women scored significantly higher on the EPDS compared with iron sufficient pregnant women.
“The study of women in the second or third trimester of pregnancy suggests that a link exists between iron deficiency and antenatal depression,” the researchers wrote.
Even after adjusting for confounding variables, the findings persisted, the researchers argued, suggesting that “iron deficiency could be an important risk factor for the development of depression during pregnancy.”
Consistent with other research results
The researchers admitted that there were several limitations in the study. Other than the very specific study population, the retrospective nature “leaves open the possibility of reverse causality—i.e., antenatal depression leads to iron deficiency, rather than the converse.”
In addition, the EPDS used is a survey but not a formal diagnostic interview for depression. Finally, the study design didn’t account for nutritional status of patients during pregnancy, and the iron deficiency may be a marker of poor nutrition in general.
Nevertheless, their findings are consistent with research showing associations between iron deficiency and depression in both general population samples and postpartum women.
“Future research with larger samples that are followed prospectively will help to determine whether widespread screening of ferritin can be recommended as a means of detecting antenatal depression risk,” they added.
Source: Journal of Obstetrics and Gynaecology Canada
Published online ahead of print, https://doi.org/10.1016/j.jogc.2017.09.027
Iron Deficiency and Risk of Maternal Depression in Pregnancy: An Observational Study
Authors: Manish Dama, Ryan J Van Lieshout, Gabriella Mattina, Meir Steiner