Table 2 Post-randomisation characteristics

Maternal

 Iodine intake at 28 weeks of gestation, µg/day^a

–

 Took non-study nutritional supplements during intervention period

Yes/no

 Diagnosed with thyroid problems during intervention period

Yes/no

 Postnatal iodine supplementation if breastfeeding

Yes/no/not applicable

 Which study group believed to be in

Intervention/control/unsure

Infant

 Apgar score at 5 min

–

 Duration of breastfeeding^b

–

 Age commenced solids

–

 Childcare attendance before primary outcome assessment

Yes/no

 Home Screening Questionnaire score

–

 Age at primary outcome assessment

–

 Unblinded before primary outcome assessment

Yes/no