Iron metabolism in African American women in the second and third trimesters of high-risk pregnancies

Authors: WELKE, LAUREN - University Of Illinois; KOENIG, MARY - University Of Illinois; Thomson, Jessica; NEMETH, ELIZABETA - University Of California; WHITE-TRAUT, ROSEMARY - University Of Chicago; MCFARLIN, BARBARA - University Of Chicago; GIURGESCU, CARMEN - Wayne State University; ENGELAND, CHRISTOPHER - Pennsylvania State University; KOMINIAREK, MICHELLE - Northwestern University; TUSSING-HUMPHREYS, LISA - University Of Chicago

Submitted to: Journal of Obstetric Gynecologic and Neonatal Nursing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2016
Publication Date: 1/27/2017
Publication URL: http://handle.nal.usda.gov/10113/5642516
Citation: Welke, L., Koenig, M.D., Thomson, J.L., Nemeth, E., White-Traut, R., Mcfarlin, B.L., Giurgescu, C., Engeland, C., Kominiarek, M., Tussing-Humphreys, L. 2017. Iron metabolism in African American women in the second and third trimesters of high-risk pregnancies. Journal of Obstetric Gynecologic and Neonatal Nursing. 46:148-158. doi: http://dx.doi.org/10.1016/j.jogn.2016.06.013.

Interpretive Summary: A high-risk pregnancy is linked to increased rates of premature birth and greater maternal and infant morbidity and mortality. African American women are more likely to be classified as a high-risk pregnancy possibly due in part to increased rates of known risk factors for high-risk pregnancy, such as obesity and gestational diabetes. These conditions have been reported to negatively impact a pregnant woman’s ability to metabolize iron, a concern since iron deficiency in the mother also is associated with greater risk for maternal and infant mortality, preterm birth, and irreversible neurocognitive defects in infants. Again, African American women are at higher risk for iron deficiency in pregnancy as compared to their white counterparts. Given these facts, this study was designed to examine maternal iron metabolism in African American women with high risk pregnancies in the second and third trimesters. African American women with high-risk pregnancies and seeking care at an urban, Midwestern, university based, maternal-fetal medicine clinic were recruited for study participation. Blood drawn from participants in the second and third trimesters was analyzed for various markers of iron status and inflammation. On average, the 32 participants were relatively young (28 years of age) and obese prior to becoming pregnant. Almost half (48%) of the participants were classified with iron deficiency as compared to 20% and 40% for general populations of pregnant white and African American women, respectively. Additionally, levels of a biomarker associated with both iron stores and inflammation were higher in this cohort of women as compared to healthy pregnant women, suggesting these women had less iron available for their body’s use. Further investigation is warranted to provide insight into why African American women are more likely to suffer from iron deficiency during pregnancy given this condition’s adverse effects on maternal and infant health.

Technical Abstract: Objective: To examine iron metabolism during the second and third trimesters in African American women with high-risk pregnancies. Design: Longitudinal pilot study. Setting: Large, university-based, urban Midwestern U.S. medical center. Participants: Convenience sample of 32 African American women with high-risk pregnancies seeking care at an urban maternal-fetal medicine clinic. Methods: Nonfasting venous blood was collected in the second and third trimesters to assess iron status, hepcidin, and systemic inflammation. Anthropometric and survey data were obtained via self-report. Descriptive statistics were calculated from these data, and changes in the clinical parameters between the second and third trimesters were evaluated via paired t tests. Associations among demographic, reproductive, anthropometric, inflammatory, and iron-related parameters were also assessed in each trimester. Results: The mean age of participant was 28 (± 6.8) years, and prepregnancy body mass index was 31.9 (± 10.7) kg/m2. In the longitudinal analysis, significant (p < 0.05) declines in serum iron, ferritin, transferrin saturation, and C-reactive protein were observed between the second and third trimesters. There was no statistically significant change in hepcidin between trimesters. When using a ferritin cut-point of less than 15 ng/ml and soluble transferrin receptor level of greater than 28.1 nmol/l, 48% of the participants (14 of 29) were classified with iron deficiency in the third trimester. Conclusion. In this pilot study, iron deficiency was prevalent among a small cohort of African American women with high-risk pregnancies. Hepcidin concentrations were greater than previously reported in healthy, pregnant, primarily White women, which suggests decreased iron bioavailability in this high-risk group.