[Supply of iodine during pregnancy--an inventory in Berlin, Germany]

Iodised salt was introduced in Germany in the early 1980s. A nation-wide study in 1996 showed that iodine levels among the population had improved since the introduction of the supplementation. The study did not separately investigate the iodine status of pregnant women. In our prospective study, we used three parameters to assess the iodine levels among pregnant women.

Between October 1999 and February 2000, we asked 109 German-speaking patients seeking prenatal care in our clinic to participate. Following informed consent, we measured goiter volume by ultrasound and collected venous blood (serum) and urine samples. We asked patients about any history of thyroid gland illnesses and about iodine supplementation which is generally given to pregnant patients in Germany. The blood and urine samples were stored at -18 degrees C until measurement. We used the iodine-creatinine-ratio to measure ioduria. Iodine was measured using the Cer-Arsenite-method (Dade-Behring). The thyroglobulin concentration in serum was measured using RIA.

The mean iodine-creatinine ratio was 181 +/- 109 microg/g, 20.4 % of the patients had a ratio between 50 and 100 microg/g which is defined as iodine deficiency I degrees (WHO). 8.7 % of the patients had thyreoglobulin levels above the cut-off value of 50 ng/ml. 12.6 % of the patients had a goiter (volume > 18 ml). 58 % of the patients were taking iodine supplements. These patients had significantly higher iodine-creatinine ratio levels (204 microg/g vs. 148 microg/g, P = 0.007) and lower serum thyroglobulin levels (38.4 vs. 34.1 pmol/l, P = 0.06) than non-supplemented patients.

The prevalence of goiter reflects an extended period of iodine deficiency. Using laboratory methods, up to 20.4 % of pregnant women were identified as having an iodine deficiency which indicates the need for a general iodine supplementation during pregnancy.