Radioiodine and pregnancy

Area of Science:

• Nuclear medicine
• Endocrinology
• Reproductive health

Background:

• The fetal thyroid gland starts accumulating radioiodine around the 12th week of gestation.
• Iodide readily crosses the placental barrier, necessitating protective measures during radioiodine administration to pregnant individuals.

Purpose of the Study:

• To outline the risks and management strategies associated with radioiodine exposure in pregnant and lactating individuals and their offspring.
• To provide guidance on safe practices concerning radioiodine administration and subsequent reproductive decisions.

Main Methods:

• Review of existing literature on radioiodine uptake by the fetal thyroid.
• Analysis of the effects of maternal radioiodine administration on fetal development and offspring neurobehavior.
• Evaluation of risks associated with incidental exposure to radioiodine from treated family members.
• Assessment of recommendations for breastfeeding and conception following radioiodine therapy.

Main Results:

• Maternal radioiodine administration can lead to fetal hypothyroidism and potential neurodevelopmental issues like attention deficits and impaired memory.
• The risk of fetal harm from indirect exposure to radioiodine is minimal if standard post-treatment guidelines are followed.
• Lactating mothers treated with radioiodine (131I) must discontinue breastfeeding; future breastfeeding is permissible.
• Pre-administration pregnancy testing is recommended for women of childbearing potential, and a 120-day waiting period post-radioiodine is advised before conception due to effects on spermatogenesis.

Conclusions:

• Careful management and adherence to guidelines are crucial to mitigate risks of radioiodine exposure to the fetus and infant.
• Informed reproductive planning, including pregnancy testing and waiting periods, is essential for individuals undergoing radioiodine treatment.