Rationale of a Cohort Study on Risk of Obstetrical Outcomes Associated with Iron Supplementation during Pregnancy

Abstract

Background: Anemia is one of the most widely prevalent disorders, affecting the lives of almost half a billion women of reproductive age, contributing to over 100,000 maternal and almost 600,000 perinatal deaths (mostly through pre-term delivery, low birth weight) each year. Increased risk of infant mortality and reduced cognitive development and reduced energy levels which affect productivity in adults are cited. During pregnancy increased requirements, inadequate intake of iron and other micronutrients and parasitic (malaria, hookworm) as wells as bacterial (mostly urinary tract) infections are the main causes. In order to reduce such maternal and neonatal burden, it has been worldwide admitted to adopt cost-effective preventive interventions during pregnancy, including iron-folic acid supplementation, de-hookworming medication and anti-malarial prevention or treatment. Intestinal absorption of iron is limited by a lot of factors including bioavailability, iron status of the woman, substances accompanying or contained in diet, chelating agents such as diet fibers or calcium salts. Any supplementation put additional constraint in terms of absorption. Unabsorbed iron is known to have pro-oxidant properties likely to induce production of free radicals. These in turn might induce oxidative stress accountable for in generation of many obstetrical outcomes. This potential link between oxidative stress resulting from free radicals hyperproduction induced by non absorbed iron and harmful maternal/perinatal conditions is rarely questioned by searchers. Objectives: To determine overall (food and supplemented) iron consumption, iron and oxidative status in a cohort of pregnant women and to seek associations between findings and adverse obstetrical outcomes. Methods: At the University Clinics of Kinshasa, we designed a protocol for a prospective cohort study dealing with clinical and biochemical parameters of oxidative stress among pregnant women iron supplemented. Women with a single pregnancy not exceeding 19 weeks without obvious pathology, regardless of age and parity, were eligible for inclusion in the study. Conclusion: This study is expected to assess consequences of oral iron supplementation during pregnancy in terms of obstetrical outcomes associated with oxidative stress linked to unabsorbed iron.

Baseline Iron Status and Indices of Oxidative Stress in a Cohort of Pregnant Women in Kinshasa, DR Congo

“…This is a cross-sectional study concerning women belonging to a prospective cohort followed at the University Clinics of Kinshasa during 10 months (September 2017 throughout June 2018), the protocol of which was recently published [3]. The study sample was represented by pregnant women with a singleton pregnancy not exceeding 19 weeks (starting point of iron supplementation), without obvious pathology likely to have a negative influence on pregnancy (hypertension, diabetes mellitus, sickle cell disease, HIV, malaria, respiratory insufficiency) and regardless of age and parity.…”

“…It is postulated that the most prevalent type of anemia during pregnancy is iron-deficient one, which makes iron administration the central part of the prevention. Due to the fact that ferrous iron salts are absorbed three times faster than ferric they should be prefered in this form [3].…”

Routine Iron Supplementation during Pregnancy: Its Reflection on Iron and Oxidative Status in a Cohort of Pregnant Women in Kinshasa, DR Congo

“…The current study was approved by the Ethics Committee of the School of Public Health of the University of Kinshasa, DR Congo, and was conducted during 10 months (from September 2017 throughout June 2018), the protocol of which was recently published [12]. The study sample was represented by pregnant women with a singleton pregnancy not exceeding 19 weeks (starting point of iron supplementation), without obvious pathology likely to have a negative influence on pregnancy (hypertension, diabetes mellitus, sickle cell disease, HIV, malaria, respiratory insufficiency) and regardless of age and parity.…”

Iron and Oxidative Status Following Routine Iron Supplementation: Reflection on Pregnancy Outcomes in a Cohort of Women in Kinshasa, DR Congo

“…The current study is a prospective observational cohort of 74 pregnant women with singleton pregnancy and was approved by the Ethics Committee of the School of Public Health of the University of Kinshasa, DR Congo. It was conducted during 10 months (from September 2017 throughout June 2018), the protocol of which was recently published [19]. The study sample was represented by pregnant women with pregnancy not exceeding 19 weeks (starting point of iron supplementation), without obvious pathology likely to have a negative influence on pregnancy (hypertension, diabetes mellitus, sickle cell disease, HIV, malaria, respiratory insufficiency) and regardless of age and parity.…”

“…Throughout confinement adverse obstetrical outcomes were registered in terms of preterm labor and premature delivery (<37 weeks of gestation), PE (hypertension considered as blood pressure ≥ 140/90mmHg), GDM (to be di-Open Journal of Obstetrics and Gynecology agnosed between weeks 26 and 28 of gestation using a glucose tolerance test according to the "Hyperglycaemia and Adverse Pregnancy Outcomes or HAPO study" [21]), PROM, prematurity (birth between 28 weeks of gestation and 37 weeks), LBW (birth weight < 2500 g), stillbirth (defined as death of a fetus after 28 weeks of gestation), perinatal mortality (deaths including stillbirths and neonatal deaths before 7 days of life), birth asphyxia or neonatal distress (defined as an Apgar score < 7 at the fifth minute) and any other neonatal or postpartum morbidity [19].…”