Risk Factors for First Trimester Iron Deficiency

Iron deficiency is the most common cause of anemia in pregnancy, which is associated with maternal and neonatal complications. The objective of this study was to identify the frequency and risk factors for isolated iron deficiency (iID) in the 1st trimester. This was a secondary analysis of a prospective cohort study to identify risk factors for iID of non-anemic pregnant individuals presenting for prenatal care in the 1st trimester from February 2022 to June 2022 at NYU Langone Health. iID was defined as serum ferritin level of ≤ 29 ng/mL. Inclusion criteria included pregnant individuals ages 18-60 years with a singleton gestation enrolled in the 1st trimester (prior to 14 weeks 0 days gestation) and were non-anemic (hemoglobin ≥11.0 g/dl). Patients were excluded if they had 1st trimester anemia or history of blood transfusion 3 months prior to pregnancy. Univariate analyses were followed by multiple logistic regression (OR [95% CI]) with statistical significance defined at p< 0.05. Of 600 patients enrolled in the study, 89 (14.8%) had 1st trimester iID. Black/African American patients (19.1% vs. 8.2%, p=0.003), those with uterine fibroids (20.2% vs. 9.4%, p=0.003), and those with higher median BMI (25.2 kg/m2 (IQR 22.7-29.6) vs. 23.6 kg/m2 (IQR 21.4-27.3), p=0.01) were more likely have to 1st trimester iID. White patients (41.6% vs. 56.6%, p=0.01) and those with a normal BMI (44.9% vs. 57.3%, p=0.04) were less likely to have 1st trimester iID. After adjusting for confounders in regression models, Black/African American patients had the strongest association with 1st trimester iID (aOR 2.18 [1.12-4.11], p=0.02), followed by uterine fibroids (aOR 2.02 [1.05-3.72], p=0.03). Overweight or obese BMIs were not identified as risk factors for 1st trimester iID. Based on our findings, Black/African American pregnant individuals and those with uterine fibroids are at highest risk for 1st trimester iID. Future studies should investigate perinatal outcomes for pregnant individuals with 1st trimester iID.