USMLE Step 2 CK Lecture Notes 2019: Obstetrics/Gynecology (Kaplan Test Prep)

(Kiana) #1

GENETIC DISORDERS


HUMAN GENETICS IN PREGNANCY


A   37-year-old G5  P0  Ab4 comes   for prenatal    care    at  7   weeks'  gestation.  She
has experienced four previous spontaneous first-trimester abortions. She is
concerned about the likelihood of her next pregnancy being successful.

Indicators for genetic counseling during pregnancy include the following:


Advanced    maternal    age:    women   age ≥35 at  increased   risk    of  fetal
nondisjunction trisomies (e.g., trisomies 21 and 18)
Incidence of chromosomal abnormalities by maternal age: the greater the
age, the greater the risk
Multiple fetal losses
Previous child: neonatal death, intellectual disability, aneuploidy, known
genetic disorder
Pregnancy or fetal losses: stillborn with birth defect, multiple pregnancy, or
fetal losses
Family history: genetic diseases, birth defects, intellectual disability,
Abnormal prenatal tests: triple marker screen, sonogram
Parental aneuploidy
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