In a double-blind, placebo-controlled trial,
Glinoer et al. supplemented pregnant Belgian women
(n = 120; median UIC 36 mg/L; biochemical criteria of
excess thyroid stimulation) with 100 mg iodine/day
or control from ~14 weeks to term.24 Treatment had no
significant effect on maternal or cord T3, FT4 and T3/T4
ratio. The treated women had significantly higher
UIC, smaller thyroid volumes, and lower TSH and Tg
concentrations, compared with controls. Newborns of
the treated group also had significantly higher UIC,
smaller thyroid volumes and lower Tg concentrations
compared with controls.
Liesenkötter et al. reported results from a quasirandom,
controlled trial of 230 mg iodine/day from 11
weeks to term in pregnant German women (n = 108;median UIC 53 mg/g creatinine; goiter rate 42.5%).25
Median UIC increased to 104 mg/g creatinine in
treated group, and median thyroid volume was significantly
lower in the newborns of the treated women
compared with controls (0.7 vs. 1.5 mL, respectively).
Treatment had no significant effect on maternal TSH,
T3, T4, thyroid volume or Tg, and had no effect on
newborn TSH.