In a study in Zaire, participants were pregnant
women attending antenatal clinics in an area of severe
iodine deficiency with a 4% cretinism rate.13–15 Pregnant
women were randomly allocated to two groups:
one received iodised oil injection, the other an injection
of vitamins. Women were on average 28 weeks
pregnant when they were treated. Psychomotor development
scores were measured in the offspring at ª72
months of age, but there was a loss to follow-up of
ª50% in both groups. The psychomotor development
scores were significantly higher in the iodine group
(mean psychomotor development score, 91 13 vs.
82 14 in the controls); the prevalences of psychomotor
scores 60 were 0.5% in the iodine group vs. 9.7%
in the controls.