Iron Absorption and Transfer to the Fetus During Pregnancy in Normal Weight and Overweight/Obese Women and the Effects on Infants Iron Status (PIANO)

Maternal Iron Absorption and Utilization and Iron Transfer to the Fetus During Pregnancy in Normal Weight and Overweight/Obese Women and the Effects on Infant Iron Status

Overweight and obesity causes low-grade systemic inflammation, which sharply increases risk for iron deficiency. Studies in our laboratory have shown that this is mainly the result of reduced dietary iron absorption because of increased hepcidin concentrations. During pregnancy, women have a large increase in iron needs because of the expansion of maternal blood volume and fetal needs. Iron deficiency anemia in infancy can impair cognitive development. Whether maternal adiposity impairs absorption and transfer of iron to the fetus, and thereby increases risk of iron deficiency in the mother and the infant is unclear.

Study Overview

• Status: Completed
• Conditions: Obesity; Overweight; Pregnancy
• Intervention / Treatment: Other: Stable iron isotope 57 (57Fe) labeled iron solution; Other: Stable iron isotope 58 (58Fe) labeled iron solution

Detailed Description

In obese subjects, hepcidin concentrations are increased and iron absorption is believed to be reduced, leading to iron deficiency over time. How all this will influence iron supply of the fetus in obese pregnancy has not been well investigated to date. Even if maternal and fetal iron uptakes are regulated separately, it is unclear to what extent maternal subclinical inflammation might influence this process. A small study by Dao et al. indicated that maternal-fetal iron transfer was impaired in obese pregnant women, possibly due to hepcidin up-regulation. In this study, both maternal BMI as well as hepcidin were negatively correlated with cord blood iron status. Maternal hepcidin and c-reactive protein were significantly higher and cord blood iron was significantly lower in the obese compared to the normal weight. Hepcidin was shown to have an effect on iron transfer across the placenta in the study by Young et al.: the transfer was increased in women with undetectable hepcidin at delivery compared to those with higher levels. As of now, clear associations between maternal BMI or maternal hepcidin concentration and fetal iron status were not shown.

• Study Type: Interventional
• Enrollment (Actual): 83
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Zurich, Switzerland, 8092
    • Human Nutrition Laboratory ETH Zurich

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• Pregnant women with either normal pre-pregnancy BMI (BMI 18.5 - 24.9kg/kg2) or with overweight or obesity (BMI > 27.5kg/m2) before pregnancy (assessed based on data reported by the women at their first visit at the hospital)
• 18 to 45 years old
• singleton pregnancy
• week of pregnancy 14±3

Exclusion Criteria:

• underlying malabsorption disease
• chronic illness, which influences iron absorption
• inflammatory status other than obesity
• medical problems known to affect iron homeostasis
• smoking during pregnancy
• no regular use of medication, which influences iron absorption

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Isotopically labeled test meal week of pregnancy 20	Other: Stable iron isotope 57 (57Fe) labeled iron solution; test meal labeled with 12 mg 57Fe
Experimental: Isotopically labeled test meal week of pregnancy 30	Other: Stable iron isotope 58 (58Fe) labeled iron solution; test meal labeled with 12 mg 58Fe

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fractional iron absorption	The fractional iron absorption from the first test meal will be calculated based on the shift of the iron isotopic ratios in the collected blood samples 14 days after administration of the isotopically labeled meal.	week 20 of pregnancy
iron transfer from the mother to the fetus in cord blood/infant	To determine the amount of iron transferred from the mother to the fetus	delivery
Fractional iron absorption	The fractional iron absorption from the second test meal will be calculated based on the shift of the iron isotopic ratios in the collected blood samples 14 days after administration of the isotopically labeled meal.	week 30 of pregnancy
infants iron status	infants iron status	over the first six months of life

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in plasma ferritin	Change in plasma ferritin	weeks of pregnancy 12, 18, 20, 28, 30, 36; 3 and 6 months after delivery
Change in Hepcidin	Change in Hepcidin	weeks of pregnancy 12, 18, 20, 28, 30, 36; 3 and 6 months after delivery
Change in transferrin receptor	Change in transferrin receptor	weeks of pregnancy 12, 18, 20, 28, 30, 36; 3 and 6 months after delivery
Change in hemoglobin	Change in hemoglobin	weeks of pregnancy 12, 18, 20, 28, 30, 36; 3 and 6 months after delivery
Change in c-reactive protein	Change in c-reactive protein	weeks of pregnancy 12, 18, 20, 28, 30, 36; 3 and 6 months after delivery
Change in interleukin-6	Change in interleukin-6	weeks of pregnancy 12, 18, 20, 28, 30, 36; 3 and 6 months after delivery
Chage in alpha-1-acid glycoprotein	Chage in alpha-1-acid glycoprotein	weeks of pregnancy 12, 18, 20, 28, 30, 36; 3 and 6 months after delivery
Change in retinol binding protein	Change in retinol binding protein	weeks of pregnancy 12, 18, 20, 28, 30, 36; 3 and 6 months after delivery
Change in riboflavin	Change in riboflavin	weeks of pregnancy 12, 18, 20, 28, 30, 36; 3 and 6 months after delivery
Assessment of children's iron needs within their first 2 years of life using an isotope dilution technique	Assessment of children's iron needs within their first 2 years of life	Follow-up blood samples at 3, 6, 12, 18, 24 months after birth
Assessment of recovery of mother's iron Status after pregnancy using an isotope dilution technique	Assessment of recovery of mother's iron Status after pregnancy	Follow-up blood samples at 3, 6, 12, 18, 24 months after delivery
infants iron status	infants iron status	over the first 24 months of life

Collaborators and Investigators

• Sponsor: Swiss Federal Institute of Technology

Publications and helpful links

General Publications

• Stoffel NU, Zimmermann MB, Cepeda-Lopez AC, Cervantes-Gracia K, Llanas-Cornejo D, Zeder C, Tuntipopipat S, Moungmaithong S, Densupsoontorn N, Quack Loetscher K, Gowachirapant S, Herter-Aeberli I. Maternal iron kinetics and maternal-fetal iron transfer in normal-weight and overweight pregnancy. Am J Clin Nutr. 2022 Apr 1;115(4):1166-1179. doi: 10.1093/ajcn/nqab406.

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2016
• Primary Completion (Actual): April 1, 2019
• Study Completion (Actual): September 1, 2020

Study Registration Dates

• First Submitted: January 8, 2016
• First Submitted That Met QC Criteria: April 18, 2016
• First Posted (Estimate): April 21, 2016

Study Record Updates

• Last Update Posted (Actual): April 23, 2021
• Last Update Submitted That Met QC Criteria: April 21, 2021
• Last Verified: April 1, 2021

More Information

Terms related to this study

• Keywords: Hepcidin; Iron absorption; Iron bioavailability
• Additional Relevant MeSH Terms: Body Weight; Overweight; Physiological Effects of Drugs; Trace Elements; Micronutrients; Pharmaceutical Solutions; Iron
• Other Study ID Numbers: PIANO