Adequate iodine and Fe intakes are imperative during pregnancy to prevent fetal defects, but such data are not available in the Democratic Republic of Congo. We aimed to assess iodine and Fe status in pregnant women from Lubumbashi.

Cross-sectional study. We measured urinary iodine concentration (UIC) in random urine samples using a modified Sandell–Kolthoff digestion method; the WHO reference medians were used to classify iodine intake as deficient, adequate, more than adequate or excessive. Serum ferritin concentrations were measured by immunoenzymatic assay and considered insufficient when <12 ng/ml.

Maternity units from rural, semi-urban and urban areas of Lubumbashi, Democratic Republic of Congo.

Two hundred and twenty-five randomly selected pregnant women attending prenatal consultation, seventy-five postpartum women and seventy-five non-pregnant women as controls.

Overall median UIC in pregnant women was 138 (interquartile range: 105–172) μg/l, indicating iodine deficiency, whereas postpartum and non-pregnant women had adequate iodine intake: median UIC = 144 μg/l and 204 μg/l, respectively. Median UIC values were lower in late pregnancy than in early pregnancy: in the first, second and third trimester respectively 255 μg/l, 70 μg/l and 88 μg/l in the rural area; 306 μg/l, 166 μg/l and 68 μg/l in the semi-urban area; and 203 μg/l, 174 μg/l and 99 μg/l in the urban area. Fe was insufficient in 39 % of pregnant women compared with 21 % of non-pregnant and postpartum women. In the third trimester, deficiencies in both iodine and Fe were high: 40 %, 12 % and 18 % in the rural, semi-urban and urban areas, respectively.

Our data suggest that pregnant women are at risk of iodine and Fe deficiencies in Lubumbashi. Country policies fighting against iodine and Fe deficiencies during pregnancy should be reinforced.