Maternal iron status in early pregnancy and birth outcomes: insights from the Baby's Vascular health and Iron in Pregnancy study

Nisreen A Alwan; Janet E Cade; Harry J McArdle; Darren C Greenwood; Helen E Hayes; Nigel A B Simpson

doi:10.1017/S0007114515001166

Maternal iron status in early pregnancy and birth outcomes: insights from the Baby's Vascular health and Iron in Pregnancy study

Nisreen A Alwan, Janet E Cade, Harry J McArdle, Darren C Greenwood, Helen E Hayes, Nigel A B Simpson

The Rowett Institute of Nutrition and Health

Research output: Contribution to journal › Article › peer-review

74 Citations (Scopus)

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Abstract

Fe deficiency anaemia during early pregnancy has been linked with low birth weight and preterm birth. However, this evidence comes mostly from studies measuring Hb levels rather than specific measures of Fe deficiency. The present study aimed to examine the association between maternal Fe status during the first trimester of pregnancy, as assessed by serum ferritin, transferrin receptor and their ratio, with size at birth and preterm birth. In the Baby VIP (Baby's Vascular health and Iron in Pregnancy) study, we recruited 362 infants and their mothers after delivery in Leeds, UK. Biomarkers were measured in maternal serum samples previously obtained in the first trimester of pregnancy. The cohort included sixty-four (18 %) small for gestational age (SGA) babies. Thirty-three babies were born preterm (9 %; between 34 and 37 weeks). First trimester maternal Fe depletion was associated with a higher risk of SGA (adjusted OR 2·2, 95 % CI 1·1, 4·1). This relationship was attenuated when including early pregnancy Hb in the model, suggesting it as a mediator (adjusted OR 1·6, 95 % CI 0·8, 3·2). For every 10 g/l increase in maternal Hb level in the first half of pregnancy the risk of SGA was reduced by 30 % (adjusted 95 % CI 0, 40 %); levels below 110 g/l were associated with a 3-fold increase in the risk of SGA (95 % CI 1·0, 9·0). There was no evidence of association between maternal Fe depletion and preterm birth (adjusted OR 1·5, 95 % 0·6, 3·8). The present study shows that depleted Fe stores in early pregnancy are associated with higher risk of SGA.

Original language	English
Pages (from-to)	1985-1992
Number of pages	8
Journal	British Journal of Nutrition
Volume	113
Issue number	12
Early online date	6 May 2015
DOIs	https://doi.org/10.1017/S0007114515001166
Publication status	Published - 28 Jun 2015

Bibliographical note

Date of Acceptance: 16/03/2015

Acknowledgements
N. A. A. was funded by a Wellcome Trust Research Training Fellowship (WT87789). H. J. M. and H. E. H. are supported by the Scottish Government’s Rural and Environment Science and Analytical Services. N. A. B. S. is supported by Cerebra. The authors’ contributions are as follows: N. A. A. was responsible for organising the study conduct, data collection and database management, performed the statistical analysis, interpreted the results and drafted the paper. N. A. A., N. A. B. S., J. E. C., H. J. M. and D. C. G. contributed to the study concept and design, and interpretation of results. H. J. M. and H. E. H. analysed the laboratory samples. J. E. C. and D. C. G. provided advice on statistical strategy and analysis. All authors have fully participated in the reporting stage
and have critically reviewed and approved the final draft of the paper.
The authors declare no conflict of interest

Keywords

iron
birth weight
preterm birth
pregnancy

Access to Document

10.1017/S0007114515001166Licence: CC BY

Maternal iron status in early pregnancy and birth outcomes
Copyright © The Authors 2015 This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Cite this

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abstract = "Fe deficiency anaemia during early pregnancy has been linked with low birth weight and preterm birth. However, this evidence comes mostly from studies measuring Hb levels rather than specific measures of Fe deficiency. The present study aimed to examine the association between maternal Fe status during the first trimester of pregnancy, as assessed by serum ferritin, transferrin receptor and their ratio, with size at birth and preterm birth. In the Baby VIP (Baby's Vascular health and Iron in Pregnancy) study, we recruited 362 infants and their mothers after delivery in Leeds, UK. Biomarkers were measured in maternal serum samples previously obtained in the first trimester of pregnancy. The cohort included sixty-four (18 %) small for gestational age (SGA) babies. Thirty-three babies were born preterm (9 %; between 34 and 37 weeks). First trimester maternal Fe depletion was associated with a higher risk of SGA (adjusted OR 2·2, 95 % CI 1·1, 4·1). This relationship was attenuated when including early pregnancy Hb in the model, suggesting it as a mediator (adjusted OR 1·6, 95 % CI 0·8, 3·2). For every 10 g/l increase in maternal Hb level in the first half of pregnancy the risk of SGA was reduced by 30 % (adjusted 95 % CI 0, 40 %); levels below 110 g/l were associated with a 3-fold increase in the risk of SGA (95 % CI 1·0, 9·0). There was no evidence of association between maternal Fe depletion and preterm birth (adjusted OR 1·5, 95 % 0·6, 3·8). The present study shows that depleted Fe stores in early pregnancy are associated with higher risk of SGA.",

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note = "Date of Acceptance: 16/03/2015 Acknowledgements N. A. A. was funded by a Wellcome Trust Research Training Fellowship (WT87789). H. J. M. and H. E. H. are supported by the Scottish Government{\textquoteright}s Rural and Environment Science and Analytical Services. N. A. B. S. is supported by Cerebra. The authors{\textquoteright} contributions are as follows: N. A. A. was responsible for organising the study conduct, data collection and database management, performed the statistical analysis, interpreted the results and drafted the paper. N. A. A., N. A. B. S., J. E. C., H. J. M. and D. C. G. contributed to the study concept and design, and interpretation of results. H. J. M. and H. E. H. analysed the laboratory samples. J. E. C. and D. C. G. provided advice on statistical strategy and analysis. All authors have fully participated in the reporting stage and have critically reviewed and approved the final draft of the paper. The authors declare no conflict of interest ",

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AU - Greenwood, Darren C

AU - Hayes, Helen E

AU - Simpson, Nigel A B

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N2 - Fe deficiency anaemia during early pregnancy has been linked with low birth weight and preterm birth. However, this evidence comes mostly from studies measuring Hb levels rather than specific measures of Fe deficiency. The present study aimed to examine the association between maternal Fe status during the first trimester of pregnancy, as assessed by serum ferritin, transferrin receptor and their ratio, with size at birth and preterm birth. In the Baby VIP (Baby's Vascular health and Iron in Pregnancy) study, we recruited 362 infants and their mothers after delivery in Leeds, UK. Biomarkers were measured in maternal serum samples previously obtained in the first trimester of pregnancy. The cohort included sixty-four (18 %) small for gestational age (SGA) babies. Thirty-three babies were born preterm (9 %; between 34 and 37 weeks). First trimester maternal Fe depletion was associated with a higher risk of SGA (adjusted OR 2·2, 95 % CI 1·1, 4·1). This relationship was attenuated when including early pregnancy Hb in the model, suggesting it as a mediator (adjusted OR 1·6, 95 % CI 0·8, 3·2). For every 10 g/l increase in maternal Hb level in the first half of pregnancy the risk of SGA was reduced by 30 % (adjusted 95 % CI 0, 40 %); levels below 110 g/l were associated with a 3-fold increase in the risk of SGA (95 % CI 1·0, 9·0). There was no evidence of association between maternal Fe depletion and preterm birth (adjusted OR 1·5, 95 % 0·6, 3·8). The present study shows that depleted Fe stores in early pregnancy are associated with higher risk of SGA.

AB - Fe deficiency anaemia during early pregnancy has been linked with low birth weight and preterm birth. However, this evidence comes mostly from studies measuring Hb levels rather than specific measures of Fe deficiency. The present study aimed to examine the association between maternal Fe status during the first trimester of pregnancy, as assessed by serum ferritin, transferrin receptor and their ratio, with size at birth and preterm birth. In the Baby VIP (Baby's Vascular health and Iron in Pregnancy) study, we recruited 362 infants and their mothers after delivery in Leeds, UK. Biomarkers were measured in maternal serum samples previously obtained in the first trimester of pregnancy. The cohort included sixty-four (18 %) small for gestational age (SGA) babies. Thirty-three babies were born preterm (9 %; between 34 and 37 weeks). First trimester maternal Fe depletion was associated with a higher risk of SGA (adjusted OR 2·2, 95 % CI 1·1, 4·1). This relationship was attenuated when including early pregnancy Hb in the model, suggesting it as a mediator (adjusted OR 1·6, 95 % CI 0·8, 3·2). For every 10 g/l increase in maternal Hb level in the first half of pregnancy the risk of SGA was reduced by 30 % (adjusted 95 % CI 0, 40 %); levels below 110 g/l were associated with a 3-fold increase in the risk of SGA (95 % CI 1·0, 9·0). There was no evidence of association between maternal Fe depletion and preterm birth (adjusted OR 1·5, 95 % 0·6, 3·8). The present study shows that depleted Fe stores in early pregnancy are associated with higher risk of SGA.

KW - iron

KW - birth weight

KW - preterm birth

KW - pregnancy

U2 - 10.1017/S0007114515001166

DO - 10.1017/S0007114515001166

M3 - Article

C2 - 25946517

SN - 0007-1145

VL - 113

SP - 1985

EP - 1992

JO - British Journal of Nutrition

JF - British Journal of Nutrition

IS - 12

ER -

Maternal iron status in early pregnancy and birth outcomes: insights from the Baby's Vascular health and Iron in Pregnancy study

Abstract

Bibliographical note

Keywords

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