Geophagia in pregnancy and its association with nutritional status: A prospective cohort study in rural north-eastern Tanzania

Background: Geophagia or soil-eating behavior is common among pregnant women in sub-Saharan Africa, however its relationship with nutritional status demands further investigation. Using a prospective pregnancy cohort from north-eastern Tanzania, we examined the characteristics of geophagia and its association with nutritional status parameters (mid-upper arm circumference (MUAC), vitamin B12, folate, ferritin, and hemoglobin) before conception and throughout the gestational period. Methods: Pregnant women (n = 530) were interviewed in each trimester regarding their soil-eating habits. Serum concentrations of vitamin B12, folate, ferritin, and hemoglobin, and MUAC were measured before conception and in each trimester. Cross-sectional comparisons between women who ate and did not eat soil were analyzed using Welch’s t-test for continuous variables and χ2-test for categorical variables. The association between changes in nutritional status parameters and the initiation of geophagia was investigated using multivariable logistic regression. Results: The prevalence of geophagia in this cohort was 27% (n = 143) with most women initiating geophagia in the third trimester. Pregnant women that ate soil had significantly lower ferritin (p = 0.001) prior to conception and at concentrations diagnostic of iron deficiency (p = 0.022) compared to women who did not eat soil. Geophagia was associated with lower ferritin (p ≤ 0.001) and lower hemoglobin (p < 0.05) in each trimester and lower folate in the third trimester (p = 0.007). A smaller decline in hemoglobin and folate across the gestational period was associated with reduced odds of initiating geophagia in the third trimester (hemoglobin: OR 0.71, p = 0.008; folate: OR 0.97, p = 0.008). There was no significant association between a change in MUAC, serum B12 or ferritin and the initiation of geophagia during pregnancy. Conclusions: Prenatal geophagia is closely related to iron and folate status. A greater decrease in hemoglobin and folate is associated with the initiation of geophagia during pregnancy. These findings are particularly relevant to low- and middle-income settings where geophagia is practiced and the prevalence of anemia in pregnancy is high.