Can you take iohexol while breastfeeding?
What LactMed says
The National Library of Medicine’s own summary, quoted in full. We do not write a verdict of our own on this question, and we do not compress theirs into a label.
Limited information indicates that maternal doses of iohexol up to 45.3 grams (containing 21 grams of iodine) produce low levels in milk. In addition, because iohexol is poorly absorbed orally, it is not likely to reach the bloodstream of the infant or cause any adverse effects in breastfed infants. The manufacturer states that withholding breastfeeding for 10 hours after administration to minimize the exposure of the infant; however, guidelines developed by several professional organizations state that breastfeeding need not be disrupted after a nursing mother receives an iodine-containing contrast medium.
Quoted from Iohexol — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised April 15, 2026.
What LactMed would consider instead
LactMed ends this record by naming the drugs it would consider in place of iohexol. Whether any of them fits depends on what you are treating — this is the database’s list, not a recommendation from us.
How much iohexol gets into breastmilk
Maternal Levels. Four mothers who were 1 week to 14 months postpartum received iohexol by rapid intravenous injection. Three received a dose of 50 mL (37.8 grams; 17.5 grams of iodine) and one received 60 mL (45.3 grams; 21 grams of iodine). Milk samples of 10 mL were collected 9 times over the 48 hours after the injection. The average iohexol milk concentration over the first 24 hours was 24.6 mg/L in the 3 women 1 week to 4 months postpartum and 130.5 mg/L in the one woman who was 14 months postpartum and weaning her infant. The authors calculated that the average amount of iohexol received by the first 3 infants over the first 24 hours would be 3.7 mg/kg or 0.5% of the weight-adjusted maternal dosage.
Infant Levels. Relevant published information was not found as of the revision date.
What has been seen in breastfed infants
A small for gestational age African-American infant was born at 36 weeks and 3 days. On the infant's fifth day of life, the mother underwent a contrast-enhanced imaging study using iohexol, after which the infant received breast milk from days 5 to 11. On day 11 of life, the neonate had an elevated thyroid-stimulating hormone and low free thyroxine levels, consistent with hypothyroidism. Urine iodine level in the infant was checked and found to be elevated. Because the thyroid alterations were thought to be transient, thyroid therapy was not given. The infant was ultimately found to have congenital thyroid dysgenesis with a genetic deletion in the gene RPS6KA3, consistent with Coffin–Lowry syndrome, and two other deletions.
Effects on milk supply
Relevant published information was not found as of the revision date.
Frequently asked questions
Can you take iohexol while breastfeeding?
Limited information indicates that maternal doses of iohexol up to 45.3 grams (containing 21 grams of iodine) produce low levels in milk. The full record is quoted on this page, and the decision is one to make with the person who prescribed it — LactMed itself states it is not a substitute for professional judgement.
What can I take instead of iohexol while breastfeeding?
LactMed lists Diatrizoate as alternate drugs to consider. That is the database's own list for this drug — whether any of them suits you depends on what you are treating.
Does iohexol pass into breastmilk?
LactMed's measured drug levels for iohexol are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking iohexol?
LactMed does not frame its records that way — it reports measured drug levels in milk and what has been observed in breastfed infants, which is what this page quotes. "Pump and dump" advice for a specific drug and dose should come from your clinician or a pharmacist, not from a general rule.
More on iohexol
LactMed states that the information it presents is not a substitute for professional judgement, and that you should consult your healthcare provider for breastfeeding advice related to your particular situation. Nothing on this page is medical advice.