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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
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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
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Frequency of chromosomal abnormalities in SAB, stillbirths, and live births?
- 50% of SAB
- 5% of stillbirths
- 0.5% of live-born babies
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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
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After 3 consecutive T1 SABs, what is the proper evaluation?
Chromosomal analysis of the couple
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What is the most common of T2 SAB?
Screening?
- Uterine or environmental
- Screening: thyroid, DM, collagen vascular disorders, hysterosalpingogram (structural abnormalities)
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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
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Which of the following drugs has the lowest potential to cause birth defects?
Alcohol
Isotretinoin (Accutane)
Tetracyclines
Progesterones
Valproic acid (Depakote)
Progesterone: incidence of birth defects for women who are on birth control pills is the same as the general population
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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
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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
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Usefulness of nuchal translucency?
timing?
- 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
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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
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What happens to a parent who has a balanced translocation?
- balanced translocations of the same chromosome are phenotypically normal
- Trisomy: many are lethal in utero (13, 18, 21 lead to syndromes)
- Monosomy: all are lethal except monosomy X
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Encephalocele: outpouching of neural tissue through a defect in the skull
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Cystic hygroma
- Often confused with an encephalocele
- It emerges from the base of the neck with an intact skull
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Hydrocephalus
Increased size of the lateral ventricles
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Anencephaly
Absence of the skull and diminished neural tissue
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Omphalocele
Defect of the abdominal wall at the insertion of the umbilical cord, which may lead to herniation of the abdominal contents
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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
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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
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CVS vs amniocentesis:
timing?
risks?
- CVS: transcervical catheter (painless), higher complication rate in midtrimester
- Amniocentesis: more complications than CVS in the first-trimester
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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
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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
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Consequence of alcohol abuse in pregnant women?
- congenital abnormalities
- Fetal alcohol syndrome: microcephaly, growth retardation, cardiac anomalies, increased incidence of mental retardation
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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)
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Tx for woman at 12 weeks GA with gonorrhea cervicitis?
Ceftriaxone
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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
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Implications of decreased AFP?
Down syndrome
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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)
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Obesity in pregnancy:
recommended weight gain?
risks?
- 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
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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
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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)
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Vegetarian diet during pregnancy
- animal sources of protein contain amino acids in the most desirable combination
- Strict vegetarian: low in vitamin B12
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Substance, risk in pregnancy:
Coffee
cocaine
marijuana
LSD
Tobacco
- 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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