exclusion of pregnant women
DESCRIPTION
Exclusion of Pregnant Women. Henry D. Royal, M.D. Associate Director Division of Nuclear Medicine Mallinckrodt Institute of Radiology Professor of Radiology Washington University School of Medicine St. Louis, MO. FDA Meeting 11/16/04. Overview. Radiation Risks During Pregnancy - PowerPoint PPT PresentationTRANSCRIPT
Exclusion of Pregnant Women
Henry D. Royal, M.D.
Associate DirectorDivision of Nuclear Medicine
Mallinckrodt Institute of Radiology
Professor of RadiologyWashington University School of Medicine
St. Louis, MOFDA Meeting 11/16/04
Overview
Radiation Risks During PregnancyPregnancy TestsMutagenesis
Radiation Effects in Pregnancy
Dose to Embryo and FetusStage of GestationCongenital Abnormalities are
Deterministic EffectsChildhood Cancer is a
Stochastic Effect
BEIR V Figure 6-1Fetal Dose (Gy)0 1.00.50.2 0.3
00.1 1.5
10
20
30
40
50
60
70Se
vere
Men
tal R
etar
dati
on (
%)
8-15 Weeks
All Gestational Ages
16-25 weeks
BEIR V Figure 6-1
BEIR V Figure 6-1
Teratogenesis
Mental Retardation is the Greatest Effect 0.4% per Rem
Decrease in IQ0.3 Units per Rem
Risk is Greatest at 8-15 Weeks Threshold May Exists at 20-40 Rem
Childhood Cancer2.2 per 1,000 (0-15 years)Relative Risk: 1.4 per RemAbsolute Risk: 0.06% per Rem
(1 Cancer per 1700 children)Controversial
ICRP 84 page 11, 2000
0 10 20 30Cases per 1,000 Births
GrowthRetardation
DevelopmentalAbnormalities
Viral Infections
ChromosomalAbnormalities
Risks of Pregnancy
Occupational Exposure During Pregnancy
0.5 Rem During Entire Pregnancy 0.05 Rem/Month Once Pregnancy Declared
NCRP Report 91, 1987
Pregnancy Testing
Given That The Risk is Small With Fetal Doses in the Few 100 mRem Range, Written Attestation Should Suffice
For Fetal Doses > 1 Rem, a Pregnancy Test Would be Prudent
Pregnancy Tests Are Not Perfect
Mutagenesis
Somatic vs Germ Cells
Mutagenesis
38,000 Parents75,000 BirthsNo Significant Differences in:1. Still Births2. Birth Weights3. Congenital
Abnormalities
4. Infant Mortality5. Child Mortality6. Leukemia7. Sex Ratio
Rare Electrophorectic Variants
Mutagenesis
ExposedThree Probable Mutations in 667,404 Loci
ControlThree Probable Mutations in 466,881 Loci
No Significant Difference
Not Demonstrated in HumansAbundant Evidence in Plants and Animals
at High Doses
Mutagenesis
10 20 30 40 500
0.05
0.1
0.15
NEJM 328:114-120, 1993Maternal Age
Prob
abili
tyGenetic Effects
All
Down’s
Conclusions About Mutagenesis
Immeasurable RiskPregnancy Should Only be Delayed If It is
Expected That the Health of the Mother Will Improve With Time