1. Effects of Radiation on the Embryo and Fetus
Lecture 28
Effects of Radiation on the Embryo and Fetus

2. Intrauterine death
Congenital abnormalities and neonatal death
Microcephaly, mental retardation
Growth retardation
Dose, dose rate, and stage in gestation
Human experience of pregnant women exposed to therapeutic dose

3. Three important stages of development Pre-implantation Organogenesis
Newly fertilized mouse egg
Three important stages of development
Pre-implantation
Organogenesis
Fetal development
3rd day –mouse embryo

4. Classic effects of radiation on Embryo and Fetus
1. Lethal effects
pre-implantation death
intra-uterine death
neonatal death
2. Malformations
Teratogenic effects
3. Growth disturbances
Effects depend on:
Dose, Stage of gestation and dose rate

5. Dose= 2 Gy

6. Intrauterine death
Congenital abnormalities and neonatal death
Microcephaly, mental retardation
Growth retardation
Dose, dose rate, and stage in gestation
Human experience of pregnant women exposed to therapeutic dose

7. Congenital malformations
(1 Gy)

8. Irradiation during the period of organogenesis
Normal
Resorbed fetuses

9. Irradiation during the period of organogenesis
Eye defects

10. Intrauterine death
Congenital abnormalities and neonatal death
Microcephaly, mental retardation
Growth retardation
Dose, dose rate, and stage in gestation
Human experience of pregnant women exposed to therapeutic dose

11. Experience in humans Medical exposures Atomic bomb survivors Effects:
Microcephaly
CNS defects
Growth retardation
For period weeks
Absorbed fetal dose (Rads)

12. Medical Radiation effects on Embryo and Fetus
Less severe abnormalities in human embryo exposed before 2-3 weeks of gestation was observed, although an increase abortion was reported.
Severe abnormalities observed between 4 and 11 weeks of gestation.
Abnormalities involving eye, skeleton, genital organs and stunted growth, microcephaly and mental retardation was observed between 11 and 16 weeks of gestation.
Weeks showed mild stunted growth, microcephaly and mental retardation.
Irradiation after 30 weeks caused functional disabilites.

13. Intrauterine death
Congenital abnormalities and neonatal death
Microcephaly, mental retardation
Growth retardation
Dose, dose rate, and stage in gestation
Human experience of pregnant women exposed to therapeutic dose

14. Comparison of human and animal data