Iodine deficiency in pregnant women residing in an area with adequate iodine intake.

OBJECTIVE: To prevent iodine deficiency disorders, the World Health Organization, United Nations Children's Fund, and International Council for the Control of Iodine Deficiency Disorders established that for a given population median urinary iodine concentrations (UIC) must be 100-199 microg/L in clinically healthy subjects and 150-249 microg/L in clinically healthy pregnant women. We evaluated whether in the urban area of Rome, Italy, where a salt iodination program (30 mg/kg) was introduced since 2005, an increased demand of iodine during pregnancy is guaranteed.

METHODS: During 2006, 51 pregnant women at first trimester of a physiologic gestation were consecutively enrolled on presentation to evaluate UIC in morning spot urine samples. As controls, 100 age-matched clinically healthy non-pregnant women were evaluated.

RESULTS: The median UICs were 182 microg/L (range 85-340 microg/L) and 74 microg/L (range 17-243 microg/L), respectively, in the control and pregnant groups. This difference was highly significant (P < 0.001). In particular, the UIC was found to be lower than adequate in 4% of control women compared with 92% of pregnant women. This difference of occurrences was highly significant (P < 0.001).

CONCLUSION: This observational study demonstrated that, despite the adequate supplementation of iodine intake, most pregnant women appear not to be protected against iodine deficiency. If confirmed in larger case studies, this finding claims the attention of relevant professionals to monitor iodine nutrition during gestation, assuming that ordinary supplementation of iodine intake seems to be sufficient only in non-gestational conditions.