What are the effects of Chernobyl (nuclear power plant) exposures on pregnancy?

From the Guidelines

Exposure to radiation from the Chernobyl nuclear disaster during pregnancy poses potential risks to the developing fetus, with effects depending on the dose received and gestational age at exposure. Women who were pregnant during or after the 1986 Chernobyl accident and received significant radiation exposure (generally above 100 mSv) faced increased risks of birth defects, developmental issues, and childhood cancers in their offspring 1. The estimated radiation dose to an adult that could potentially cause temporary or permanent sterility in that adult is approximately 500 rads (5 Gy), while embryonic death may occur at a dose of 10 to 50 rad (100 to 500 mGy) 1.

Key Considerations

• The maximum permitted dose for the fetus is 50 mrem (0.5 mSv) per month, with a total gestational dose equivalent of 500 mrem (5 mSv) 1.
• The risk of congenital malformation or developing a malignancy after irradiation in utero, with doses of the order of 1 rem over the course of gestation, is estimated at 1 in 500 (0.2%) 1.
• Fetal exposure to high doses of radiation can also potentially cause mental retardation, with the magnitude of this risk approximately 1 chance in 25 (4%) per 10 rem (100 mSv) 1.

Recommendations

• If you're concerned about past Chernobyl-related exposure during pregnancy, consult with a healthcare provider specializing in radiation effects or maternal-fetal medicine for personalized assessment 1.
• They may recommend detailed medical history review, ultrasound monitoring, and possibly amniocentesis to check for chromosomal abnormalities.
• For current pregnancies in formerly affected areas, radiation levels have significantly decreased over time, though some regions still have elevated background radiation 1.

Important Timeframes

• The developing fetus is most vulnerable during organogenesis (weeks 2-8 of pregnancy), when radiation can cause structural abnormalities.
• Later exposure may affect neurological development and increase lifetime cancer risk.
• Radiation damages rapidly dividing cells and can cause DNA mutations, which explains its particular impact on developing embryos and fetuses 1.

From the Research

Chernobyl Exposures During Pregnancy

• The Chernobyl nuclear accident led to increased radioactive radiation in Europe, with foods contaminated via the food chain, accounting for about 80% of the total irradiation exposure 2.
• Studies have shown that thyroid cancer risk is increased among people exposed to radioactive iodine, particularly vulnerable populations such as pregnant and breastfeeding women, children, and neonates 3, 4.
• Potassium iodide (KI) can effectively block radioactive iodine from being absorbed by the thyroid gland if taken immediately after a radiation release, with a protective effect of up to 78.9% for adults 5.
• The risk of thyroid cancer after a nuclear reactor emergency is higher in countries with nutritional iodine deficiency, and in patients with thyrotoxicosis, hypothyroidism, or endemic goitre not being adequately treated 4.
• The evidence of radiation effects in embryos and fetuses exposed to Chernobyl fallout suggests that current legal frameworks for radiation exposure limits may be incomplete, and that physical dosimetric models may have underestimated the effective exposure 6.
• Mother's milk, amniotic fluid, and placenta of newborns were found to have increased concentrations of radionuclides I-131, Cs-134, and Cs-137 after the Chernobyl accident, but guideline values were not exceeded 2.