Maternal iron status and intrauterine growth retardation

The objective of this study was to compare the iron status of 356 mother-baby pairs who had intrauterine growth retardation (IUGR) with 356 mother-baby pairs who had appropriate weight for gestational age (AGA). Mothers were selected in 1991/92 from 4 hospitals in Campinas city, Brazil, where 95% of deliveries take place. Gestational age of the newborns was determined by the Capurro method. Newborns were classified as having IUGR according to the Lubchenco birthweight for gestational age standard. Haemoglobin (Hb), haematocrit (Ht) and ferritin were determined, respectively, by the cyanmethaemoglobin method, an haematocrit centrifuge, and an immunoenzymetric assay. Mean levels of Hb and Ht were higher in IUGR (16.4 g/dL; 51.7%) than in AGA babies (15.7 g/dL; 49.7%) (P < 0.001), as a consequence of intrauterine hypoxia. Higher maternal levels of ferritin (>50 mu g/L) were more common in IUGR than in AGA mothers (P < 0.001). Forty-seven percent (335/712) of the IUGR and AGA mothers were anaemic (Hb less than or equal to 11.0 g/dL), but only 4.4% (31/356) of them had low levels of ferritin (less than or equal to 10 mu g/L). We advise further large epidemiological studies involving IUGR and AGA mother-baby pairs, elucidating the mechanisms underlying the plasma-volume changes in pregnancy, and the prevalence of iron-deficiency anaemia assessed by different indicators, in view of the fact that ferritin can be affected by inflammation and infection, important risk factors for IUGR in developing countries.