Associations between Maternal Iron Supplementation in Pregnancy and Changes in Offspring Size at Birth Reflect Those of Multiple Micronutrient Supplementation.

Clive J Petry,Ieuan A Hughes,David B Dunger,Ken K Ong

doi:10.3390/nu13072480

Clive J Petry, Ieuan A Hughes + Show 2 more

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https://doi.org/10.3390/nu13072480

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Journal: Nutrients	Publication Date: Jul 20, 2021
Citations: 9	License type: CC BY 4.0

Affiliation: University of Cambridge, MRC Epidemiology Unit

Abstract

It was previously observed that in a population of a high-income country, dietary multiple micronutrient supplementation in pregnancy was associated with an increased risk of gestational diabetes (GDM) and increased offspring size at birth. In this follow-up study, we investigated whether similar changes are observed with dietary iron supplementation. For this we used the prospective Cambridge Baby Growth Study with records of maternal GDM status, nutrient supplementation, and extensive offspring birth size measurements. Maternal iron supplementation in pregnancy was associated with GDM development (risk ratio 1.67 (1.01–2.77), p = 0.048, n = 677) as well as offspring size and adiposity (n = 844–868) at birth in terms of weight (β’ = 0.078 (0.024–0.133); p = 0.005), head circumference (β’ = 0.060 (0.012–0.107); p = 0.02), body mass index (β’ = 0.067 (0.014–0.119); p = 0.01), and various skinfold thicknesses (β’ = 0.067–0.094; p = 0.03–0.003). In a subset of participants for whom GDM statuses were available, all these associations were attenuated by adjusting for GDM. Iron supplementation also attenuated the associations between multiple micronutrient supplementation and these same measures. These results suggest that iron supplementation may mediate the effects associated with multiple micronutrient supplementation in pregnancy in a high-income country, possibly through the increased risk of developing GDM.

Highlights

Evidence from middle and low-income countries suggests that dietary supplementation with multiple micronutrients in pregnancy is beneficial in terms of reducing the prevalence of preterm births and low birth weight babies, as well as the numbers born small for their gestational age (SGA) [1], its value in high-income countries is more controversial
Multiple micronutrient supplementation was associated with increased maternal gestational diabetes (GDM) risk that may underpin the associations with increased offspring size at birth
Sensitivity analyses were performed by repeating the association analyses in women who supplemented their diets with iron alone and by excluding those women who reported a diagnosis of anaemia in pregnancy

Summary

Introduction

Accepted: 19 July 2021 evidence from middle and low-income countries suggests that dietary supplementation with multiple micronutrients in pregnancy is beneficial in terms of reducing the prevalence of preterm births and low birth weight babies, as well as the numbers born small for their gestational age (SGA) [1], its value in high-income countries is more controversial. Multiple micronutrient supplementation was associated with increased maternal gestational diabetes (GDM) risk that may underpin the associations with increased offspring size at birth At present, it is not known which individual or group of micronutrients caused the effects associated with multiple micronutrient supplementation in this study. It does not appear to be folic acid supplementation, as our assessment of effects in pregnancy produced results that failed to reflect those of supplementation with multiple micronutrients [3]. Another candidate micronutrient for underpinning associations with multiple micronutrient supplementation in pregnancy is iron

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