Iodine nutrition during pregnancy in Toronto, Canada.

Objective: To evaluate the status of iodine nutrition among pregnant women presenting for routine antenatal care in Toronto, Canada, as determined by the median urine iodine concentration (UIC) of this population.

Methods: A cross-sectional, observational study was conducted involving 142 pregnant women recruited from four low-risk antenatal outpatient clinics in Toronto, Canada. Subjects completed a questionnaire and provided a spot urine sample for the measurement of iodine concentration.

Results: Mean maternal age was 33.8 ± 4.3 years. Mean gestational age was 29.3 ± 7.8 weeks. The median UIC was 221 μg/L (interquartile range, 142 to 397 μg/L). Six women (4.2%) had urine iodine levels <50 μg/L, and 36 women (25.4%) had levels between 50 and 150 μg/L.

Conclusion: This cohort of primarily Caucasian, well-educated, and relatively affluent pregnant women in Toronto, Canada, are iodine sufficient, perhaps due to universal salt iodization and/or other dietary and lifestyle factors.