Ahmed GroupAhmed GroupLecture 28Lecture 28
Effects of Radiation on the Embryo and Fetus
Lecture 28Lecture 28
Ahmed GroupAhmed GroupLecture 28Lecture 28
Intrauterine deathIntrauterine deathCongenital abnormalities and neonatal deathCongenital abnormalities and neonatal deathMicrocephaly, mental retardationMicrocephaly, mental retardationGrowth retardationGrowth retardationDose, dose rate, and stage in gestationDose, dose rate, and stage in gestationHuman experience of pregnant women exposed to Human experience of pregnant women exposed to therapeutic dosetherapeutic dose
Ahmed GroupAhmed GroupLecture 28Lecture 28
Three important stages of development1. Pre-implantation2. Organogenesis3. Fetal development
Newly fertilized mouse egg
3rd day –mouse embryo
Ahmed GroupAhmed GroupLecture 28Lecture 28
Classic effects of radiation on Embryo and Fetus
1. Lethal effectspre-implantation deathintra-uterine deathneonatal death
2. Malformations Teratogenic effects
3. Growth disturbances
Effects depend on:
Dose, Stage of gestation and dose rate
Ahmed GroupAhmed GroupLecture 28Lecture 28 Dose= 2 Gy
Ahmed GroupAhmed GroupLecture 28Lecture 28
Intrauterine deathIntrauterine deathCongenital abnormalities and neonatal deathCongenital abnormalities and neonatal deathMicrocephaly, mental retardationMicrocephaly, mental retardationGrowth retardationGrowth retardationDose, dose rate, and stage in gestationDose, dose rate, and stage in gestationHuman experience of pregnant women exposed to Human experience of pregnant women exposed to therapeutic dosetherapeutic dose
Ahmed GroupAhmed GroupLecture 28Lecture 28
(1 Gy)Congenital malformations
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Resorbed fetuses
Irradiation during the period of organogenesis
Normal
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Irradiation during the period of organogenesis
Eye defects
Ahmed GroupAhmed GroupLecture 28Lecture 28
Intrauterine deathIntrauterine deathCongenital abnormalities and neonatal deathCongenital abnormalities and neonatal deathMicrocephaly, mental retardationMicrocephaly, mental retardationGrowth retardationGrowth retardationDose, dose rate, and stage in gestationDose, dose rate, and stage in gestationHuman experience of pregnant women exposed to Human experience of pregnant women exposed to therapeutic dosetherapeutic dose
Ahmed GroupAhmed GroupLecture 28Lecture 28
Experience in humans1. Medical exposures2. Atomic bomb survivors
Effects:1. Microcephaly2. CNS defects3. Growth retardation
For period 16-25 weeks
Absorbed fetal dose (Rads)
Ahmed GroupAhmed GroupLecture 28Lecture 28
Medical Radiation effects on Embryo and Fetus
1. Less severe abnormalities in human embryo exposed before 2-3 weeks of gestation was observed, although an increase abortion was reported.
2. Severe abnormalities observed between 4 and 11 weeks of gestation.
3. Abnormalities involving eye, skeleton, genital organs and stunted growth, microcephaly and mental retardation was observed between 11 and 16 weeks of gestation.
4. Weeks 16-20 showed mild stunted growth, microcephaly and mental retardation.
5. Irradiation after 30 weeks caused functional disabilites.
Ahmed GroupAhmed GroupLecture 28Lecture 28
Intrauterine deathIntrauterine deathCongenital abnormalities and neonatal deathCongenital abnormalities and neonatal deathMicrocephaly, mental retardationMicrocephaly, mental retardationGrowth retardationGrowth retardationDose, dose rate, and stage in gestationDose, dose rate, and stage in gestationHuman experience of pregnant women exposed to Human experience of pregnant women exposed to therapeutic dosetherapeutic dose
Ahmed GroupAhmed GroupLecture 28Lecture 28
Comparison of human and animal data
Ahmed GroupAhmed GroupLecture 28Lecture 28
Ahmed GroupAhmed GroupLecture 28Lecture 28
Ahmed GroupAhmed GroupLecture 28Lecture 28