What do systematic reviews say?

Any supplement containing iodine vs same supplement without iodine or no treatment/placebo (maternal outcomes)

Any supplement containing iodine showed no clear difference in perinatal mortality compared with same supplement without iodine or no treatment/placebo (child… (low certainty).

• Iodine supplementation for women during the preconception, pregnancy and postpartum period 2017 · Cochrane Headline outcomes only
  RR 0.66 [0.42, 1.03]
  1 study · 399 participants
  Low

Recombinant human thyrotropin‐aided radioiodine vs radioiodine

• Recombinant human thyrotropin (rhTSH)‐aided radioiodine treatment for non‐toxic multinodular goitre 2021 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 28 participants
  Very low

Povidone iodine rinse vs Saline rinse or placebo

Povidone iodine rinse showed no clear difference in mortality compared with saline rinse or placebo; GRADE not reported.

• Oral hygiene care for critically ill patients to prevent ventilator‐associated pneumonia 2020 · Cochrane All outcomes
  RR 1.00 [0.66, 1.50]
  2 studies · 217 participants
  GRADE not reported

Povidone iodine rinse vs usual or supportive care

• Oral hygiene care for critically ill patients to prevent ventilator‐associated pneumonia 2020 · Cochrane All outcomes
  Povidone iodine versus usual care: single study (67 participants), no evidence of a difference in mortality.
  1 study · 67 participants
  GRADE not reported

Iodine supplementation vs control

Iodine supplementation showed no clear difference in mortality before hospital discharge compared with control (high certainty).

• Iodine supplementation for the prevention of mortality and adverse neurodevelopmental outcomes in preterm infants 2019 · Cochrane Headline outcomes only
  RR 1.01 [0.72, 1.42]
  2 studies · 1380 participants
  High