Participants and methods
Participants
We enrolled 313 pregnant women into a cross-sectional voluntary screening study, which was coordinated by the physicians and nurses of the Health Care System in Debrecen. The ages of the women were 26.8 6 5.2 (range 17±47) years and the gestational ages were 23.6 6 7.9 (6±39) weeks. Multivitamin products, which may contain iodine, are routinely offered to pregnant women by gynaecologists. The consumption of these drugs and the use of iodized salt were elicited by detailed history and four groups were established according to the form of iodine supplementation: group A, no iodine supplementation (n 119); group B, regular use of iodized salt, no consumption of iodinecontainingmultivitamins (n 50); group C, taking iodine-containing multivitamins, no use of iodized salt (n 91); group D, regular use of iodized salt and iodine-containing multivitamin tablets (n 53). Overall, 46% of women consumed iodine-containing multivitamin products. The gestation times of those in the nonmultivitamin consuming groups (A and B: 24.6 6 8.1 weeks) and the multivitamin consuming groups (C and D: 23.9 6 7.4 weeks) did not differ significantly. To assess the iodine supply in the general population, samples from 220 non-pregnant women were also analysed