Ahmed Group Lecture 28 Effects of Radiation on the Embryo and Fetus Lecture 28.

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Effects of Radiation on the Embryo and Fetus

Lecture 28Lecture 28

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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

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Three important stages of development1. Pre-implantation2. Organogenesis3. Fetal development

Newly fertilized mouse egg

3rd day –mouse embryo

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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

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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

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(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

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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

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Experience in humans1. Medical exposures2. Atomic bomb survivors

Effects:1. Microcephaly2. CNS defects3. Growth retardation

For period 16-25 weeks

Absorbed fetal dose (Rads)

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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

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Comparison of human and animal data

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