Association between low MCV in early pregnancy and perinatal mental health in the Japan Environment and Children's Study and the possible effect of iron deficiency.

Postpartum anemia and iron deficiency are associated with postpartum depression. This study investigated the association between a low mean corpuscular volume (MCV) without anemia (which implies early-stage iron deficiency) in early pregnancy and perinatal mental health outcomes. The fixed data from the Japan Environment and Children's Study (JECS), a Japanese nationwide birth cohort, were used. Perinatal mental health was assessed using the Kessler 6-item psychological distress scale (K6) in mid-pregnancy and the Edinburgh Postnatal Depression Scale (EPDS) at 1- and 6-months postpartum. Among the 3635 women with MCVs <85 fL in early pregnancy, the proportions of women with K6 scores ≥13 in mid-pregnancy and EPDS scores ≥9 at 1- and 6-months postpartum were 2.7 %, 12.8 %, and 9.9 %, respectively, compared with the 33,242 women with MCVs ≥85 fL at 1.9 %, 11.9 %, and 9.0 %, respectively. Multivariate logistic regression models showed that an MCV <85 in early pregnancy was associated with a K6 score ≥ 13 in mid-pregnancy and an EPDS score ≥ 9 at 1- and 6-months postpartum (adjusted odds ratio (95 % confidence interval): 1.48 (1.16–1.87), 1.14 (1.01–1.28), and 1.09 (0.95–1.24), respectively). Low MCV values do not necessarily represent iron deficiency. Ferritin, currently the best indicator of iron deficiency, was not measured in the JECS. This study results suggest that a low MCV without anemia in early pregnancy is associated with a slightly increased risk of perinatal mental health deterioration. • MCV in early pregnancy and perinatal mental health was examined in a large cohort. • Low MCV without anemia in early pregnancy slightly declines perinatal mental health. • Iron deficiency should be managed from preconception to ensure maternal mental health. [ABSTRACT FROM AUTHOR]