Risk Summary
Hysterosalpingography is contraindicated in pregnant women due to the potential risk to the fetus from an intrauterine procedure [see
Contraindications (
4)
]. The use of Lipiodol before or during pregnancy may interfere with thyroid function in both the pregnant woman
and her fetus and may affect fetal development. There are maternal, fetal, and neonatal clinical considerations for women who are exposed to Lipiodol either before or during pregnancy (see Clinical Considerations). Rare pregnancy outcomes reported in the post marketing setting with Lipiodol use in pregnant women are insufficient to evaluate for a drug-associated risk of major birth defects or miscarriage (see Data). Animal reproduction studies have not been conducted using the indicated routes of administration of Lipiodol, it was not embryotoxic or teratogenic in animal studies with oral administration.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a
background risk of major birth defects, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of
major birth defects and miscarriages in clinically recognized pregnancies is 2-4% and 15-20%, respectively.
Clinical Considerations
Maternal adverse reactions
The use of Lipiodol before or during pregnancy may interfere with the thyroid function of the pregnant woman. Untreated hypothyroidism in pregnancy is associated with adverse perinatal outcomes, such as spontaneous abortion, preeclampsia, preterm birth, abruptio placentae, and fetal death. Consider thyroid function testing during pregnancy if a woman was exposed to Lipiodol either before or during pregnancy or if clinically indicated [see
Warnings and Precautions (
5.4)
].
Fetal / Neonatal adverse reactions
The use of Lipiodol before or during pregnancy causes iodide transfer across the placenta which may interfere with fetal thyroid function
and may affect fetal development. Untreated hypothyroidism is associated with increased fetal risk of low birth weight, fetal distress, and
impaired neuropsychological development. Consider thyroid function testing in infants whose mothers were exposed to Lipiodol before
and during pregnancy or if clinically indicated [see
Warnings and Precautions (
5.4)
].
Data
Human Data
In a prospective study, twenty-two euthyroid women with infertility underwent hysterosalpingography, and thyroid stimulating hormone,
serum iodine concentration, and urinary iodide/creatine excretion were evaluated at 4, 8, 12, 24 weeks. Six patients were followed upto12 months. The median value of urinary iodide excretion peaked at four weeks post-procedure and remained elevated at 8, 12, 24 weeks post-procedure compared to pre-procedure. Three patients showed elevated TSH (5 uIU/L) with normal T4 at 4 or 8 weeks after
hysterosalpingography.
In addition, there are post marketing reports of goiters and hypothyroidism in fetuses and infants whose mothers were exposed to Lipiodol for hysterosalpingography prior to pregnancy.
Animal Data
Lipiodol was not embryotoxic or teratogenic in rats after oral administration of up to 250 mg Iodine/kg each day between gestation days 6 to 17, or in rabbits after 4-5 intermittent (once every three days) oral administrations of 12.5 mg Iodine/kg between gestation days 6 to 18. Maternal
toxicity was observed in rats at 250 mg Iodine/kg/day.