Iron requirements increase significantly during pregnancy. Current recommendations for iron intake in pregnant and lactating women (PLW) are mainly based on factorial estimates and extrapolated from non-PLW. High-quality quantitative data on iron requirements in PLW are lacking, particularly in Sub- Saharan Africa where anaemia and infections are common. The primary objective of this study is to use the stable iron isotope technique to determine iron requirements and assess iron absorption and losses in PLW living in Kenya. In this prospective observational study, we will enrol pregnant women in the first trimester (n = 250) from a previous study cohort (n=1000) who participated in an iron absorption study at least 12 months ago and received the stable iron (Fe) isotope 57Fe. This 57Fe has now distributed and equilibrated throughout the women's body iron. Once enrolled in the present study, following Kenyan guidelines, women will receive standard prenatal care, including routine daily iron and folate supplementation. We will collect venous blood samples in each trimester and at delivery, and during the first 6 months of lactation in the mothers and infants (heel prick samples). To directly assess dietary iron absorption, in a randomly selected subset of women (n=35), oral and intravenous stable iron isotope tracers (54Fe, 58Fe) will be administered in the 2nd and 3rd trimesters.
Study Type
OBSERVATIONAL
Enrollment
250
In the CO-rebreathing method, a dedicated apparatus is used for inhaling and rebreathing a very small bolus of CO through a spirometer for \~2 min, which is absorbed through the lungs and binds to Hb, and then the increase of HbCO content of blood is measured 8 min after the CO inhalation. The increase of COHb in blood samples can then be used to precisely calculate Hb mass and blood volume
Participants randomly assigned to the sub-group, will receive 54Fe with a test meal in the second and third trimester for assessment of dietary iron absorption
Participants randomly assigned to the sub-group, will receive intravenous 58Fe in the second and third trimester for assessment of erythrocyte iron incorporation
Msambweni Referral Hospital
Msambweni, Kenya
RECRUITINGIron absorbed, lossed and gained in the first trimester
isotope dilution
Time frame: Change in 57Fe tracer abundance between gestational age 6, 10 and 15 weeks
Iron absorbed, lossed and gained in the second trimester
isotope dilution
Time frame: Change in 57Fe tracer abundance between gestational age 15, 20 and 25 weeks
Iron absorbed, lossed and gained in the third trimester
isotope dilution
Time frame: Change in 57Fe tracer abundance between gestational age 25, 30 and 35 weeks
Iron absorbed, lossed and gained throughout pregnancy
isotope dilution
Time frame: Change in 57Fe tracer abundance between gestational age 6, 10, 15, 20, 25, 30 and 35 weeks
Iron absorbed, lossed and gained in lactating women
isotope dilution
Time frame: Change in 57Fe tracer abundance between 6, 14 and 24 weeks postpartum
Iron absorbed, lossed and gained in infancy
isotope dilution
Time frame: Change in 57Fe tracer abundance between age 6, 14 and 24 weeks
Fractional iron absorption (%) in the second trimester
shift in iron isotopic ratios
Time frame: gestational age 20 weeks
Fractional iron absorption (%) in the third trimester
shift in iron isotopic ratios
Time frame: gestational age 30 weeks
Erythrocyte iron incorporation (%) in the second trimester
shift in iron isotopic ratios
Time frame: gestational age 20 weeks
Erythrocyte iron incorporation (%) in the third trimester
shift in iron isotopic ratios
Time frame: gestational age 30 weeks
Hemoglobin concentration (g/dl)
Hb
Time frame: gestational age 6 weeks
Hemoglobin concentration (g/dl)
Hb
Time frame: gestational age 10 weeks
Hemoglobin concentration (g/dl)
Hb
Time frame: gestational age 15 weeks
Hemoglobin concentration (g/dl)
Hb
Time frame: gestational age 20 weeks
Hemoglobin concentration (g/dl)
Hb
Time frame: gestational age 25 weeks
Hemoglobin concentration (g/dl)
Hb
Time frame: gestational age 30 weeks
Hemoglobin concentration (g/dl)
Hb
Time frame: gestational age 36 weeks
Hemoglobin concentration (g/dl)
mother
Time frame: 6 weeks postpartum
Hemoglobin concentration (g/dl)
infant
Time frame: age 6 weeks
Hemoglobin concentration (g/dl)
mother
Time frame: 14 weeks postpartum
Hemoglobin concentration (g/dl)
infant
Time frame: age 14 weeks
Hemoglobin concentration (g/dl)
mother
Time frame: 24 weeks postpartum
Hemoglobin concentration (g/dl)
infant
Time frame: age 24 weeks
Mean corpuscular volume (fl)
MCV
Time frame: gestational age 6 weeks
Mean corpuscular volume (fl)
MCV
Time frame: gestational age 10 weeks
Mean corpuscular volume (fl)
MCV
Time frame: gestational age 20 weeks
Mean corpuscular volume (fl)
MCV
Time frame: gestational age 30 weeks
Mean corpuscular volume (fl)
mother
Time frame: 6 weeks postpartum
Mean corpuscular volume (fl)
infant
Time frame: age 6 weeks
Mean corpuscular volume (fl)
mother
Time frame: 14 weeks postpartum
Mean corpuscular volume (fl)
infant
Time frame: age 14 weeks
Mean corpuscular volume (fl)
mother
Time frame: 24 weeks postpartum
Mean corpuscular volume (fl)
infant
Time frame: age 24 weeks
Erythropoietin concentration (mU/ml)
EPO
Time frame: gestational age 10 weeks
Erythropoietin concentration (mU/ml)
EPO
Time frame: gestational age 20 weeks
Erythropoietin concentration (mU/ml)
EPO
Time frame: gestational age 30 weeks
Erythropoietin concentration (mU/ml)
EPO
Time frame: 6 weeks postpartum
Erythropoietin concentration (mU/ml)
EPO
Time frame: 14 weeks postpartum
Erythropoietin concentration (mU/ml)
EPO
Time frame: 24 weeks postpartum
Erythroferrone concentration (ng/ml)
ERFE
Time frame: gestational age 10 weeks
Erythroferrone concentration (ng/ml)
ERFE
Time frame: gestational age 20 weeks
Erythroferrone concentration (ng/ml)
ERFE
Time frame: gestational age 30 weeks
Erythroferrone concentration (ng/ml)
ERFE
Time frame: 6 weeks postpartum
Erythroferrone concentration (ng/ml)
ERFE
Time frame: 14 weeks postpartum
Erythroferrone concentration (ng/ml)
ERFE
Time frame: 24 weeks postpartum
Hepcidin concentration (ng/ml)
Hep
Time frame: gestational age 10 weeks
Hepcidin concentration (ng/ml)
Hep
Time frame: gestational age 20 weeks
Hepcidin concentration (ng/ml)
Hep
Time frame: gestational age 30 weeks
Hepcidin concentration (ng/ml)
Hep
Time frame: 6 weeks postpartum
Hepcidin concentration (ng/ml)
Hep
Time frame: 14 weeks postpartum
Hepcidin concentration (ng/ml)
Hep
Time frame: 24 weeks postpartum
Serum ferritin concentration (ug/l)
SF
Time frame: gestational age 10 weeks
Serum ferritin concentration (ug/l)
SF
Time frame: gestational age 20 weeks
Serum ferritin concentration (ug/l)
SF
Time frame: gestational age 30 weeks
Serum ferritin concentration (ug/l)
mother
Time frame: 6 weeks postpartum
Serum ferritin concentration (ug/l)
infant
Time frame: age 6 weeks
Serum ferritin concentration (ug/l)
mother
Time frame: 14 weeks postpartum
Serum ferritin concentration (ug/l)
infant
Time frame: age 14 weeks
Serum ferritin concentration (ug/l)
mother
Time frame: 24 weeks postpartum
Serum ferritin concentration (ug/l)
infant
Time frame: age 24 weeks
Soluble transferrin receptor concentration (ul/l)
sTfR
Time frame: gestational age 10 weeks
Soluble transferrin receptor concentration (ul/l)
sTfR
Time frame: gestational age 20 weeks
Soluble transferrin receptor concentration (ul/l)
sTfR
Time frame: gestational age 30 weeks
Soluble transferrin receptor concentration (ul/l)
mother
Time frame: 6 weeks postpartum
Soluble transferrin receptor concentration (ul/l)
infant
Time frame: age 6 weeks
Soluble transferrin receptor concentration (ul/l)
mother
Time frame: 14 weeks postpartum
Soluble transferrin receptor concentration (ul/l)
infant
Time frame: age 14 weeks
Soluble transferrin receptor concentration (ul/l)
mother
Time frame: 24 weeks postpartum
Soluble transferrin receptor concentration (ul/l)
infant
Time frame: age 24 weeks
C-reactive protein concentration (mg/l)
CRP
Time frame: gestational age 10 weeks
C-reactive protein concentration (mg/l)
CRP
Time frame: gestational age 20 weeks
C-reactive protein concentration (mg/l)
CRP
Time frame: gestational age 30 weeks
C-reactive protein concentration (mg/l)
mother
Time frame: 6 weeks postpartum
C-reactive protein concentration (mg/l)
infant
Time frame: age 6 weeks
C-reactive protein concentration (mg/l)
mother
Time frame: 14 weeks postpartum
C-reactive protein concentration (mg/l)
infant
Time frame: age 14 weeks
C-reactive protein concentration (mg/l)
mother
Time frame: 24 weeks postpartum
C-reactive protein concentration (mg/l)
infant
Time frame: age 24 weeks
alpha-glycoprotein concentration (mg/dl)
AGP
Time frame: gestational age 10 weeks
alpha-glycoprotein concentration (mg/dl)
AGP
Time frame: gestational age 20 weeks
alpha-glycoprotein concentration (mg/dl)
AGP
Time frame: gestational age 30 weeks
alpha-glycoprotein concentration (mg/dl)
mother
Time frame: 6 weeks postpartum
alpha-glycoprotein concentration (mg/dl)
infant
Time frame: age 6 weeks
alpha-glycoprotein concentration (mg/dl)
mother
Time frame: 14 weeks postpartum
alpha-glycoprotein concentration (mg/dl)
infant
Time frame: age 14 weeks
alpha-glycoprotein concentration (mg/dl)
mother
Time frame: 24 weeks postpartum
alpha-glycoprotein concentration (mg/dl)
infant
Time frame: age 24 weeks
Blood volume (l)
Time frame: gestational age 10 weeks
Blood volume (l)
BV
Time frame: gestational age 20 weeks
Blood volume (l)
BV
Time frame: gestational age 30 weeks
Blood volume (l)
BV
Time frame: 6 weeks postpartum
Blood volume (l)
BV
Time frame: 14 weeks postpartum
Blood volume (l)
BV
Time frame: 24 weeks postpartum
Intestinal fatty acid binding protein
I-FABP
Time frame: gestational age 10 weeks
Intestinal fatty acid binding protein
I-FABP
Time frame: gestational age 20 weeks
Intestinal fatty acid binding protein
I-FABP
Time frame: gestational age 30 weeks
Retinol binding protein
RBP
Time frame: gestational age 10 weeks
Retinol binding protein
RBP
Time frame: gestational age 20 weeks
Retinol binding protein
RBP
Time frame: gestational age 30 weeks
soluble CD14
sCD14
Time frame: gestational age 10 weeks
soluble CD14
sCD14
Time frame: gestational age 20 weeks
soluble CD14
sCD14
Time frame: gestational age 30 weeks
Insulin-like growth factor 1
IGF-1
Time frame: gestational age 10 weeks
Insulin-like growth factor 1
IGF-1
Time frame: gestational age 20 weeks
Insulin-like growth factor 1
IGF-1
Time frame: gestational age 30 weeks
Fibroblast growth factor 21
FGF21
Time frame: gestational age 10 weeks
Fibroblast growth factor 21
FGF21
Time frame: gestational age 20 weeks
Fibroblast growth factor 21
FGF21
Time frame: gestational age 30 weeks
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