Iodine deficiency in pregnancy in Denmark. Regional variations and frequency of individual iodine supplementation.

Iodine requirements are increased during pregnancy and lactation and adequate iodine intake is important for normal brain development of the fetus/newborn child. The aim of the present study was to evaluate the extent to which this increase in iodine requirement is met in pregnant women living in various regions of Denmark. One hundred and fifty-two healthy pregnant women admitted to five different Danish departments of obstetrics participated in the study. Iodine status was evaluated by measurement of iodine in spot urine at day five after delivery and by careful history of the intake of iodine containing vitamin/mineral tablets. Approximately one third of the women had received tablets containing iodine. In women who had not received iodine supplementation urinary iodine was low with a median value of 39.7 micrograms/g creatinine (Aalborg 28, Randers 33, Ringkøbing 34, Arhus 43 and Copenhagen 62 micrograms/g creatinine). These values are far below internationally recommended levels. The consequences remain to be evaluated and no firm recommendations can be given. It seems reasonable, however, to recommend a high intake of food containing iodine (e.g. milk products) during pregnancy and lactation. Since nearly all the women took some kind of vitamin/mineral supplementation it could be considered to advocate intake of vitamin/mineral tablets containing iodine.