OB shelf - quiz

  1. After initial SAB in first trimester, what is the risk of recurrence?
    • No difference than it was prior to miscarriage
    • 15% of all known pregnancies end in first trimester SAB
  2. What proportion of 45,X (Turner) and Trisomy 21 (Down) make it to term?
    • 45,X: 99% are lost before term. Frequency of live birth is 1:2000
    • Trisomy 21: 75% are lost before term
  3. Frequency of chromosomal abnormalities in SAB, stillbirths, and live births?
    • 50% of SAB
    • 5% of stillbirths
    • 0.5% of live-born babies
  4. After 3 first-trimester SAB, what is the chance of live birth of future pregnancy with and without treatment?
    • Without treatment: live birth rate approaches 50%
    • With treatment: 70 to 85% live birth rate
  5. After 3 consecutive T1 SABs, what is the proper evaluation?
    Chromosomal analysis of the couple
  6. What is the most common of T2 SAB?
    • Uterine or environmental
    • Screening: thyroid, DM, collagen vascular disorders, hysterosalpingogram (structural abnormalities)
  7. Does having ≥ 3 T1 SABs increase a patient's risk for having a baby with Down syndrome?
    • Yes, the risk of aneuploidy is increased with multiple miscarriages
    • Paternal age does not matter till after 55
    • Induced ovulation does not increase risk
  8. Which of the following drugs has the lowest potential to cause birth defects?
    Isotretinoin (Accutane)
    Valproic acid (Depakote)
    Progesterone: incidence of birth defects for women who are on birth control pills is the same as the general population
  9. Threshold for X-ray in a pregnant woman, GA 10 weeks?
    • Generally thought to be 10 rads
    • First trimester: developing organ systems are affected
    • late pregnancy: brain is more sensitive
  10. Exercise in pregnant women?
    • Can maintain exercise during pregnancy if they had previously been accustomed to exercising prior to becoming pregnant
    • There is no set pulse defined as an upper limit
    • Non-weight-bearing exercise will minimize the risk of injury
    • Physiologic changes persist from 4 to 6 weeks following delivery, women should not resume the intensity of prepregnancy exercise immediately following delivery
  11. Usefulness of nuchal translucency?
    • Between 10 and 13 weeks, nuchal translucency is a useful marker for increased risk of chromosome abnormalities, including Down syndrome
    • Nuchal translucency will almost always disappear by 15 weeks
  12. Achondroplasia: inheritance?
    pregnancy complications?
    • Autosomal dominant inheritance
    • New mutations account for 90% of all cases of the disorder
    • Achondroplastic women almost always require cesarean section
    • Achondroplastic fetuses should be delivered by cesarean section to minimize trauma to the neck
  13. What happens to a parent who has a balanced translocation?
    • balanced translocations of the same chromosome are phenotypically normal
    • Gamete formation: translocated chromosome cannot divide, resulting in either two copies or no copies in the meiosis product (trisomy or monosomy)
    • Trisomy: many are lethal in utero (13, 18, 21 lead to syndromes)
    • Monosomy: all are lethal except monosomy X
  14. Image Upload 1
    Encephalocele: outpouching of neural tissue through a defect in the skull
  15. Cystic hygroma
    • Often confused with an encephalocele
    • It emerges from the base of the neck with an intact skull
  16. Hydrocephalus
    Increased size of the lateral ventricles
  17. Anencephaly
    Absence of the skull and diminished neural tissue
  18. Omphalocele
    Defect of the abdominal wall at the insertion of the umbilical cord, which may lead to herniation of the abdominal contents
  19. maternal serum α-fetoprotein (MSAFP)
    uses, timing, reasons for elevated MSAFP?
    • MSAFP may be performed between 15 and 21 weeks to screen for neural tube defects
    • Early in pregnancy (<19weeks): if the value is <4.0 MOM, a second MSAFP is drawn
    • High value >4.0 MOM, or gestation approaching limit of test (19+ weeks): skip repeat and go to ultrasound and possibly amniocentesis
    • Elevated (causes): anencephaly, twins, wrong GA, fetal demise
  20. what is the fastest method of determining fetal cytogenetics?
    • Chorionic villus sampling: direct, extremely rapid diagnosis
    • Amniocentesis, cordocentesis, cystic hygroma aspiration, and CVS are all able to obtain fetal tissue
    • Amniocentesis: cells require culture to obtain adequate number
    • Percutaneous umbilical blood sampling (PUBS): 2 to 3 days of culturing before karyotype is obtained
  21. CVS vs amniocentesis:
    • CVS: transcervical catheter (painless), higher complication rate in midtrimester
    • Amniocentesis: more complications than CVS in the first-trimester
  22. Which immunization should be avoided in pregnancy?
    • Live attenuated viruses are contraindicated: measles and mumps (and rubella, since it is contained with the others), varicella, polio
    • Bacterial vaccines (cholera, plague, typhoid): can be used
  23. Which vaccines can be used in pregnancy?
    Inactivated or formalin-killed: influenza, typhoid fever, tentanus, pertusis, diphtheria toxoid, rabies, poliomyelitis, cholera, plague, Rocky Mountain spotted fever
  24. Consequence of alcohol abuse in pregnant women?
    • congenital abnormalities
    • Fetal alcohol syndrome: microcephaly, growth retardation, cardiac anomalies, increased incidence of mental retardation
  25. Treatment of UTI in pregnant women: which abx to use/avoid?
    • Penicillins and cephalosporins are ok
    • Avoid: Bactrim
    • Tetracycline: fetal dental anomalies in T2-T3, teratogen in T1
    • Chloramphenicol: may cause gray baby syndrome (vomiting, impaired respiration, hypothermia, cardiovascular collapse)
    • Trimethoprim-sulfamethoxazole (Bactrim): contraindicated in T3 (kernicterus)
  26. Tx for woman at 12 weeks GA with gonorrhea cervicitis?
  27. Neural tube defects
    risk in population? risk with previously affected children?
    Risk factors?
    • General population: 1.4 to 2/1000
    • Previously affected children: 3 to 4%
    • Risk factors: hyperthermia (sauna baths), at time of neural tube formation
    • Not influenced by maternal age
  28. Implications of decreased AFP?
    Down syndrome
  29. MSAFP sensitivity?
    • MSAFP will pick up 90% of neural tube defects
    • Positive predictive value: 2 to 6% (most elevated AFP pregnancies do not have NTDs!)
    • Unexplained high AFP: associated with adverse pregnancy outcomes (low birth weight, placental abruption, oligohydramnios, fetal death in utero)
  30. Obesity in pregnancy:
    recommended weight gain?
    • Morbidly obese women do NOT need to gain the 25 to 35 lbs recommended to women of normal weight
    • Risks: complications during pregnancy, diabetes, hypertension, fetal macrosomia, cesarian section
  31. Epilepsy in pregnancy:
    risk to fetus?
    risk with medications?
    • Epileptics without medication: offspring have 2 to 3 times the risk of congenital anomalies (seizures cause transient reduction in blood flow)
    • Risk with medications: even greater risk. Many Rx impair folate metabolism
    • Valproic acid: 1 to 2% risk of spina bifida
  32. Jewish ancestry:
    increase risk for...
    • Tay-sachs (carrier 1/30)
    • Canavan's disease (carrier 1/40)
    • Gaucher's disease (carrier 1/12 to 1/25)
    • white northern european: cystic fibrosis (carrier 1/25)
  33. Vegetarian diet during pregnancy
    • animal sources of protein contain amino acids in the most desirable combination
    • Strict vegetarian: low in vitamin B12
  34. Substance, risk in pregnancy:
    • Coffee: >5 cups of coffee is associated with slightly increased risk of SAB
    • Cocaine: placental abruption, congenital anomalies (skull defects, disruptions in urinary tract development, limb defects, cardiac anomalies)
    • Marijuana: no associated adverse effects
    • LSD: not a human teratogen
    • Tobacco: SAB, preterm labor, growth restriction, placental abruption, placenta previa, ADD, behavior and learning problems
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OB shelf - quiz
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