Adiposity and Iron Requirements in Pregnancy

The main aim of this study is to investigate the influence of adiposity on the difference in response to 25 or 50 mg of daily iron supplementation during pregnancy. The primary aim is to determine the influence of maternal adiposity on adjusted maternal ferritin concentrations in response to 25 mg or 50 mg iron supplementation in pregnancy. The secondary outcomes of this study include: investigating the impact of maternal body fat on various maternal iron biomarkers (such as haemoglobin, soluble transferrin receptor, hepcidin, transferrin saturation, and other haematological markers) in response to either 25 mg or 50 mg iron supplementation during pregnancy, evaluating changes in adjusted ferritin concentrations and other iron markers throughout pregnancy relative to the dosage of iron supplementation received, determining the effect of maternal body fat on neonatal iron biomarkers in response to maternal iron supplementation, assessing changes in markers of inflammation in response to iron supplementation during pregnancy, and examine changes in mental health scores in response to iron supplementation during pregnancy.

This is a double-blind randomised controlled intervention study, in which 312 pregnant women with singleton pregnancy, without current complications, aged ≥ 18 years and BMI ≥ 18.5 kg/m2 will be recruited. Participants who are taking multivitamins will be included. They will be asked to discontinue any current supplementation. Pregnant women with anaemia, iron deficiency, high risk of iron overload, history of bariatric surgery, who are planning home birth, are currently involved in another research study, and those who cannot speak or understand English language will be excluded.

Blood samples and anthropometric and body composition measurements will be taken at different points in the pregnancy (12, 28, 36 gestational weeks) and an umbilical cord blood sample at the time of birth. Blood concentrations of iron and inflammation markers will be analysed. General, dietary intake and lifestyle information will be collected, through a Health and Lifestyle questionnaire and a 4-day diary. Additionally, participants will complete a questionnaire about their mental health and gastrointestinal symptoms. The compliance of the supplementation will be evaluated at each timepoint. Additionally, participants will receive a telephone call to evaluate possible adverse effects and compliance of the supplementation between the timepoints (18, 24 and 32 weeks of gestation). In the event that a participant has been prescribed iron treatment, anaemia diagnosis at any time during pregnancy or the occurrence of any adverse outcome such as miscarriage, the participant will be withdrawn from the study. Electronic forms prepared in RedCap will be used to collect data.