The association between maternal anemia during pregnancy and preterm birth

Maternal anemia is one of the most serious health problems during pregnancy. The causes of anemia include iron deficiency, parasitic diseases, micronutrient deficiencies, and hereditary hemoglobinopathies. Because the reported association between maternal anemia and preterm labor in different studies is varied depending on the month of pregnancy this study aims to determine this relationship after adjustment for potential confounders.

A case-control study was conducted among 801 pregnant women (267 cases and 534 controls) in Sardashat, Iran from October 2012 to October 2013. Hemoglobin (Hb) values were measured for all women participating in the study during the first and second trimesters of pregnancy, and the average Hb values were presented. Statistical analyzes were performed with logistic regression.

The mean age of participants was 26.4 ± 5.25 years for the case group and 27.2 ± 6.51 years for the control group. Preterm birth was associated with maternal anemia during pregnancy [aOR = 2.69 (95% CI; 1.46 to 4.95)] even after adjusting for confounding effects including maternal age, history of abortion [aOR = 2.41 (95% CI; 1.42 to 4.08)], history of preterm birth [aOR = 11.38 (95% CI; 3.48 to 37.22)], obesity (aOR: 3.441; CI95%: 1.18-10.06), parity [aOR = 0.42 (95% CI; 0.25 to 0.69)], preeclampsia/eclampsia [aOR = 6.08 (95% CI; 2.64 to 14)], and GDM [aOR = 4.80 (95% CI; 2.02 to 11.41)]).

Early detection and adequate treatment of anemia during pregnancy can help reduce the prevalence of preterm birth.