Relationships between Maternal Obesity and Maternal and Neonatal Iron Status.

Angela Flynn,Jane Sandall,Scott Nelson,On Behalf ,Melissa Whitworth,Annette Briley,Nisreen Alwan,Shahina Begum,Sara White,Carolyn Gill,Mairead Kiely,Lucilla Poston,Deirdre Murray,Gladys Latunde-Dada,Eugene Oteng-Ntim,Kathryn Dalrymple,Thomas Sanders,Ruth Bell,Louise Kenny

doi:10.3390/nu10081000

Abstract

Obesity in pregnancy may negatively influence maternal and infant iron status. The aim of this study was to examine the association of obesity with inflammatory and iron status in both mother and infant in two prospective studies in pregnancy: UPBEAT and SCOPE. Maternal blood samples from obese (n = 245, BMI ≥ 30 kg/m2) and normal weight (n = 245, BMI < 25 kg/m2) age matched pregnant women collected at approximately 15 weeks’ gestation, and umbilical cord blood samples collected at delivery, were analysed for a range of inflammatory and iron status biomarkers. Concentrations of C- reactive protein and Interleukin-6 in obese women compared to normal weight women were indicative of an inflammatory response. Soluble transferrin receptor (sTfR) concentration [18.37 nmol/L (SD 5.65) vs. 13.15 nmol/L (SD 2.33)] and the ratio of sTfR and serum ferritin [1.03 (SD 0.56) vs. 0.69 (SD 0.23)] were significantly higher in obese women compared to normal weight women (P < 0.001). Women from ethnic minority groups (n = 64) had higher sTfR concentration compared with white women. There was no difference in maternal hepcidin between obese and normal weight women. Iron status determined by cord ferritin was not statistically different in neonates born to obese women compared with neonates born to normal weight women when adjusted for potential confounding variables. Obesity is negatively associated with markers of maternal iron status, with ethnic minority women having poorer iron statuses than white women.

Highlights

Normal fetal growth and development is dependent upon maternal iron sufficiency during pregnancy
In order to investigate the association of maternal obesity with neonatal iron status, we examined inflammatory and iron metabolism markers in cord blood obtained at delivery
Our findings add to the growing evidence of the detrimental effect of obesity on maternal iron status, which may be an additional risk factor, but hepcidin was not a regulatory factor

Summary

Introduction

Normal fetal growth and development is dependent upon maternal iron sufficiency during pregnancy. Iron deficiency (ID) is common in young women of reproductive age; in Europe, a recent estimate suggests that the prevalence of ID is 10 to 32% [2]. Rates of obesity in pregnancy have significantly increased in recent years, with UK women reported to have the highest prevalence in Europe (25.2%) [10], and maternal obesity is associated with most major adverse maternal and fetal outcomes [11]. In non-pregnant populations, there is evidence to suggest an association between obesity and increased risk of ID, with a meta-analysis of the available data concluding that overweight and obese individuals have lower serum iron, transferrin saturation, and a higher risk of iron deficiency [12]

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