Timing of umbilical cord-clamping and infant anaemia: the role of maternal anaemia Brittany Blouin 1,2 , Mary E. Penny 4 , Mathieu Maheu-Giroux 2 , Martı ´n Casapı ´a 5 , Eder Aguilar 6 , Herma ´nn Silva 6 , Hilary M. Creed-Kanashiro 4 , Serene A. Joseph 1,2 , Anita Gagnon 3 , Elham Rahme 2 , Theresa W. Gyorkos 1,2 1 Department of Epidemiology, Biostatistics and Occupational Health, McGill University, 2 Division of Clinical Epidemiology, Research Institute of the McGill University Health Centre, and 3 School of Nursing and Department of Obstetrics and Gynecology, McGill University, Montreal, Canada, 4 Instituto de Investigacio ´n Nutricional, Lima, 5 Asociacio ´n Civil Selva Amazo ´nica, and 6 Hospital Iquitos ‘‘Ce ´sar Garayar Garcı ´a’’, Iquitos, Peru Background: Evidence from randomized controlled trials has shown that delayed cord-clamping is beneficial to infant iron status. The role of maternal anaemia in this relationship, however, has not been established. Objective: To determine the effect of maternal anaemia at delivery on the association between timing of umbilical cord-clamping and infant anaemia at 4 and 8 months of age. Methods: A cohort of pregnant women admitted to the labour room of Hospital Iquitos (Iquitos, Peru) and their newborns were recruited into the study during two time periods (18 May to 3 June and 6–20 July 2009). Between the two recruitment periods, the hospital’s policy changed from early to delayed umbilical cord-clamping. Maternal haemoglobin levels were measured before delivery, and the time between delivery and cord-clamping was recorded at delivery for the entire cohort. Mother–infant pairs were followed-up at 4 (n5207) and 8 months (n5184) post partum. Infant haemoglobin levels were measured at follow-up visits. Data were analysed using logistic regression models. Results: The prevalence of maternal anaemia (Hb ,11.0 g/dl) at delivery was 22%. Infant haemoglobin levels at 4 and 8 months of age were 10.4 g/dl and 10.3 g/dl, respectively. Infant haemoglobin levels did not differ significantly between infants born to anaemic mothers and those born to non-anaemic mothers at either 4 or 8 months of age. However, the association between the timing of cord-clamping and infant anaemia was modified by the mother’s anaemia status. Significant benefits of delayed cord-clamping in preventing anaemia were found in infants born to anaemic mothers at both 4 months (aOR50.59, 95% CI 0.36–0.99) and 8 months (aOR50.38, 95% CI 0.19–0.76) of age. Conclusion: The study contributes additional evidence in support of delayed cord-clamping. This intervention is likely to have most public health impact in areas with a high prevalence of anaemia during pregnancy. Keywords: Anaemia, Developing countries, Haemoglobin, Child health, Umbilical cord Introduction Anaemia is a major health problem worldwide and is estimated to affect 24.8% of the global population in developed and developing countries. 1 The primary cause of anaemia (in 50% of cases 2 ) is iron deficiency, which is among the most important factors which contribute to the global burden of disease. 3 Iron deficiency during gestation and infancy can have devastating effects on both neural development and behavioural outcomes, and many of these negative consequences are not reversed by iron therapy. 4 Recently, delaying umbilical cord-clamping has been identified as one of four effective interventions to combat iron deficiency during the first 6 months of life. 5 An additional 15–40 ml of blood volume per kg of birthweight can be delivered to the infant through the umbilical cord by allowing placental transfusion of blood to complete. 6,7 This can increase total blood volume by an estimated 30–50%, 6,7 thus providing an additional 30–75 mg of iron at birth. 6–8 Maximizing placental transfusion of blood takes approximately 3 minutes. 9 Randomized controlled trials have demonstrated improved iron status in infants in whom cord- clamping was delayed compared with infants in whom Correspondence to: T W Gyorkos, Division of Clinical Epidemiology, McGill University Health Centre, Royal Victoria Hospital Campus (V Building), 687 Pine Avenue West, Montreal, QC, Canada H3A 1A1. Fax: z514 934 8293; email: theresa.gyorkos@mcgill.ca ß W. S. Maney & Son Ltd 2013 DOI 10.1179/2046905512Y.0000000036 Paediatrics and International Child Health 2013 VOL. 33 NO.2 79