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Genetic Counseling Boards > Prenatal Genetics > Flashcards

Prenatal Genetics Flashcards

1
Q

Gestational Age

A

date of pregnancy from LMP; includes first two weeks of ovarian cycle

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2
Q

Fertilization Age

A

date of pregnancy from fertilization; GA - 2 weeks

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3
Q

1st Trimester

A

1 - 13 weeks

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4
Q

2nd Trimester

A

14 - 27 weeks

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5
Q

3rd Trimester

A

28- 40 weeks

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6
Q

Gravida

A

pregnancies

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7
Q

Para/Parity

A

completed pregnancies >20w

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8
Q

GTPAL

A

gravida, term (deliveries >37w), preterm (deliveries between 20-37w), abortions (miscarriages and terminations <20w), living

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9
Q

Folic Acid Supplementation Recommendations

A

starting prior to conception, 400mcg daily or 4mg daily if prior history of ONTDs

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10
Q

% Unplanned Pregnancies

A

45%

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11
Q

Carrier Screening

A

genetic testing to identify couples who are at risk of having a child with various genetic conditions (usually AR, some XL)

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12
Q

Common Conditions on Carrier Screening

A
  • cystic fibrosis
  • spinal muscular atrophy
  • ethnicity-based conditions (Tay-Sachs, Gaucher, Canavan, familial dysautonomia, hemoglobinopathies)
  • fragile X syndrome (not standard)
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13
Q

Cystic Fibrosis

A
  • carrier frequency: 1/25
  • F508del occurs in 70% of cases
  • ACOG and ACMG recommend core panel of 23 mutations that identifies 49-98% of carriers
  • present on NBS via immunoreactive trypsinogen testing
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14
Q

Spinal Muscular Atrophy

A
  • carrier frequency: 1/40
  • 95% of cases due to homozygous deletions
  • 2% de novo cases
  • ACOG and ACMG recommend SMA carrier screening for all couples
  • some labs test for SNP in intron 7 (g.27134T>G) to determine if copy number 2 in cis or trans; presence of SNP increases chance they’re in cis
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15
Q

Ashkenazi Jewish Conditions

A
  • ACOG recommends screening for 4 conditions (Canavan, CF, familial dysautonomia, TSD - DNA and enzyme)
  • ACMG recommends screening for 11 conditions (Bloom, Canavan, CF, familial dysautonomia, Fanconi anemia C, Gaucher, mucolipidosis type IV, Niemann-Pick A/B, SMA, TSD - DNA and enzyme)
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16
Q

Tay Sachs Disease

A
  • AJ carrier frequency: 1/30
  • Cajun/French Canadian carrier frequency: 1/50
  • 3 HEXA mutations account for up to 98% of TSD in AJ
  • enzyme testing detects 98% of carriers regardless of ethnicity
  • when doing enzyme assay, important to do leukocytes on pregnant women and women on OCP
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17
Q

Canavan Disease

A
  • carrier frequency: 1/57
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18
Q

Familial Dysautonomia

A
  • carrier frequency: 1/30

- most individuals homozygous for c.2204+6>C

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19
Q

Gaucher Disease (type 1)

A
  • carrier frequency: 1/10-1/15
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20
Q

Hemoglobinopathies

A
  • structural hemoglobinopathies: HbS, HbC, HbE
  • thalassemias
  • carrier frequency for sickle cell in African Americans: 1/10
  • for patient at increased rick for hemoglobinopathy given ethnicity, both CBC and hemoglobin electrophoresis should be performed
  • ethnic backgrounds with increased risk: African, Mediterranean, Middle Eastern, Southeast Asian, West Indian
  • usually detected on NBS
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21
Q

Fragile X Syndrome

A
  • 1/260 females are carriers
  • normal: <45 repeats
  • intermediate/gray zone: 45-54 repeats
  • premutation: 55-200 repeats
    full mutation: >200 repeats’
  • AGG interruptions usually appear every 9-10 CGG repeats and can modify risk
  • ACOG and ACMG support offering testing to women with family history of FX-related disorders, women with a personal history of POI or elevated FSH <40y, women who request carrier screening
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22
Q

Expanded Carrier Screening

A
  • technologies vary between full-exon sequencing and targeted genotyping of predefined pathogenic variants
  • as per ACOG, ethnic-specific, pan-ethnic, and expanded carrier screening are acceptable options
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23
Q

% Pregnancies with major anatomic malformations

A

2-3% with cardiac and GU anomalies most common

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24
Q

Most common genetic cause of miscarriage and birth defects

A

aneuploidy

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25
Q

Incidence of chromosomal abnormalities in live births

A

1/150

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26
Q

Risk Factors for Trisomies

A
  • maternal age
  • younger women generally have more children than older women, so majority of pregnancies affected occur in younger women
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27
Q

Do monosomies have an age-related risk?

A

no

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28
Q

Does triploidy have an age-related risk?

A

no

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29
Q

Methods of Screening for Aneuploidy

A
  • age
  • serum screening
  • ultrasound
  • cfDNA/NIPS
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30
Q

Age

A
  • AMA = 35y at EDD
  • 35y is arbitrary cutoff that originates from when amnios were first routinely used
  • risk of DS = risk of miscarriage from amnio (1/200)
  • 27% detection rate
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31
Q

First Trimester Screening

A
  • analyte evaluation: PAPP-A, hCG
  • ultrasound evaluation (11-14w): CRL, NT (>2.5-3mm abnormal - f/u with invasive testing, early anatomy scan, fetal echo), nasal bone
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32
Q

FTS Patterns

A
  • DS: increased NT, decreased PAPP-A, increased hCG

- T18/T13: increased NT, decreased PAPP-A and hCG

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33
Q

Second Trimester Screening

A
  • triple screen: AFP, hCG, uE3; 69% detection for DS
  • quad screen: AFP, hCG (made by placenta), uE3, inhibin A; 80% detection for DS and ONTD; 15w - 22w; may be combined with FTS
  • penta screen: AFP, hCG, uE3, inhibin A, hyperglycosylated hCG; 83% detection for DS
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34
Q

STS Patterns

A
  • ONTDs: increased AFP
  • DS: decreased AFP, decreased uE3, increased hCG, increased inhibin A
  • T18/T13: decreased AFP, decreased uE3, decreased hCG, inhibin A N/A
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35
Q

Other Problems Affecting STS Analytes

A
  • wrong dates (inhibin A helpful)
  • miscarriage
  • stillbirth
  • IUGR
  • infant death/IUFD
  • HTN/preeclampsia
  • antepartum hemorrhage
  • oligohydramnios
  • placental abnormalities
  • low uE3 may also indicate SLOS, X-linked ichthyosis, steroid sulfatase deficiencies
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36
Q

msAFP

A
  • performed during second trimester
  • if elevated, increased risk for ONTDs; f/u with AFAFP, ACHE, anatomy scan
  • other reasons for elevated AFP include underestimated GA, ventral wall defect, unrecognized twin gestation, fetal demise, abnormality in fetal kidneys, placental insufficiency, maternal malignancy, adverse outcomes
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37
Q

T/F: Additional screening for aneuploidy in women who have negative screening is recommended

A

False

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38
Q

T/F: Simultaneous testing with multiple screening methodologies for aneuploidy is recommended

A

False

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39
Q

T/F: Woman with a positive result on serum screening may consider NIPS if they want to avoid invasive testing

A

True

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40
Q

NIPS

A
  • fetal component of cfDNA released into maternal circulation primarily from placental cells undergoing apoptosis and comprises 3-13% of total cfDNA in maternal blood
  • reliably performed after 9-10w GA
  • MPS based NIPS detects triploidy since extra amounts of chromosome present above what’s expected
  • SNP based NIPS can be used in twin pregnancies, for surrogates or egg donor pregnancies, to detect triploidy and vanishing twins
  • if positive, f/u with invasive testing with amniocentesis > CVS with karyotype or microarray
  • T13 and Turner more commonly associated with CPM
  • low fetal fraction may associated with aneuploidy
  • no call results may be due to sample problem, assay failure, low fetal fraction, obesity, aneuploidy
  • false positives may be due to CPM, vanishing twin, rare autosomal trisomies, large segmental aberrations, fetal sex discordance, maternal acquired or consitutional alterations, non-malignant maternal disease, benign maternal del/dups
  • false negatives may be due to high BMI, early gestational age, hemolysis in sample, maternal anticoagulation therapy, true fetal mosaicism, normal vanishing twin, maternal deletion and trisomy in fetus
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41
Q

Fetal Sex Discordance on NIPS

A
  • u/s and karyotype male, NIPS female: low fetal fraction, placenta sex chromosome mosaicism, demise of female co-twin
  • NIPS and karyotype male, u/s female: SLOS, mutations in sex development genes
  • NIPS and karyotype female, u/s male: CAH, SRY translocation
  • u/s and karyotype female, NIPS male: placental sex chromosome mosaicism, demise of male co-twin, maternal history of transplantation from male donor, recent blood transfusion from male donor
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42
Q

% Of first trimester miscarriages due to aneuploidy

A

50%

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43
Q

% Of pregnancies overall that miscarry

A

10-15%

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44
Q

Other uses for NIPS

A
  • microdeletions/duplications
  • single gene disorders (especially APA)
  • genome wide (not recommended, CMA recommended instead)
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45
Q

First Trimester Ultrasound

A
  • establishes viability
  • fetal number, chorionicity, vanishing twin
  • gestational age
  • view uterus
  • early detection of congenital anomalies
  • early aneuploidy screening
  • patient and family bonding (heart rate, pictures)
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46
Q

Second Trimester Ultrasound

A
  • examine fetal anatomy
  • fetal size
  • aneuploidy screening
  • placental location
  • cervical length measurement
  • patient and family bonding (fetal sex, 3D u/s pictures)
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47
Q

Additional Ultrasounds

A
  • 3D/4D imaging
  • biophysical profile
  • color doppler flow
  • fetal echo
  • transvaginal ultrasound
  • guidance for diagnostic procedures
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48
Q

Soft Markers

A

anatomic findings on u/s that are not congenital anomalies and may be normal variants that resolve on their own

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49
Q

Increased Nuchal Fold

A
  • soft marker
  • thickening of fetal neck area
  • strongest second-trimester marker
  • increased risk of DS, Noonan
  • fetal echo recommended
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50
Q

Intracardiac Echogenic Focus

A
  • soft marker
  • echogenic area in region of papillary muscles of fetal heart
  • common in Asians
  • increased risk for DS
  • no association with structural cardiac abnormalities or dysfunction
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51
Q

Renal Pyelectasis

A
  • soft marker
  • dilation of renal pelvis that may be uni/bilateral, stable, progressive, or resolves
  • more common in male fetuses
  • increased risk for DS, urinary tract abnormalities
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52
Q

Echogenic Bowel

A
  • soft marker
  • fetal bowel as bright as bone but may be a subjective finding
  • may be normal variant
  • increased risk for aneuploidy, CMV infection, CF, intra-amniotic bleeding, GI tract abnormality
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53
Q

Shortened Long Bones

A
  • soft marker
  • some ethnic variation present (Caucasian femoral length > African American, Asian)
  • short humerus marker for DS
  • short long bones may be marker for skeletal dysplasia
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54
Q

Choroid Plexus Cyst

A
  • soft marker
  • cysts within fetal choroid plexus that result from entrapment of CSF in tangled villi
  • 95% resolve by end of 2nd trimester
  • increased risk for T18
  • in absence of aneuploidy, not associated with increased risk for brain problems/delays
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55
Q

Ventriculomegaly

A
  • soft marker
  • dilation of fetal cerebral ventricles
  • may be mild (normal neurodevelopment), moderate (most likely normal neurodevelopment), severe (need shunt)
  • male fetuses more commonly affected
  • marker for DS
  • fetal MRI recommended
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56
Q

Single Umbilical Artery/2-Vessel Cord

A
  • soft marker
  • most common anomaly of umbilical cord
  • increased risk for GU anomalies, cardiac anomalies, IUGR, aneuploidy (if not isolated)
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57
Q

Hypoplastic/Absent Nasal Bone

A
  • soft marker
  • little to no ossification of nasal bone observed
  • may be normal variant
  • significantly increases risk for T212
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58
Q

T/F: If >1 marker detected, risk for aneuploidy increases

A

True

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59
Q

T/F: Detection of a soft marker after negative NIPS significantly increases risk for aneuploidy

A

False

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60
Q

Structural Abnormalities

A
  • significantly increase risk for fetal morbidity and mortality
  • present in 2-3% of all pregnancies
  • majority detected in second trimester
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61
Q

Structural Abnormalities Detected in First Trimester

A

acrania, anencephaly, cystic hygroma, severe heart defects

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62
Q

Congenital Heart Defects

A
  • structural abnormality
  • most common birth defect; 1-2% of all live births
  • may be due to syndromic pathogenic CNVs, aneuploidy, single gene disorders, environmental, mutifactorial causes
  • may be suspected in first trimester by increased NT
  • fetal echo, fetal u/s, prenatal diagnosis, cardiology consultation recommended
  • recurrence risk: 1-4% if isolated
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63
Q

AV Canal

A

DS

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64
Q

Coarctation of Aorta

A

Turner

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65
Q

Tetralogy of Fallot

A

22q11.2 (other conotruncal heart defects common too)

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66
Q

Ebstein’s anomaly

A

Lithium exposure

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67
Q

Pulmonary Valve Stenosis

A

Noonan

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68
Q

Supravalvular Aortic Stenosis

A

Williams

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69
Q

Anencephaly

A
  • structural abnormality (ONTD)
  • failure of closure of anterior neural tube
  • multifactorial etiology
  • associated with T18
  • likely to lead to IUFD
  • recurrence risk: 3-4%
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70
Q

Encephalocele

A
  • structural abnormality (CNTD)
  • skin-covered defect affecting cranium in occipital, frontal, or parietal regions
  • prognosis and severity dependent on how much neural tissue involved
  • associated with T13
  • fetal MRI recommended
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71
Q

Myelomeningocele

A
  • structural abnormality (most common ONTD)
  • failure of vertebral arches to close prior to 6th week of pregnancy leading to protrusion of neural elements and meninges
  • often located in lumbosacral region (bowel/bladder functions affected, ambulation affected)
  • associated with T18
  • may be observed in u/s by cranial changes and clubfoot
  • fetal MRI recommended
  • prenatal repair may be an option
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72
Q

Lemon Sign

A

head bilaterally flattened in frontal region; myelomeningocele

73
Q

Banana Sign

A

cerebellum rounded and width decreased; myelomeningocele

74
Q

Spina Bifida

A
  • structural abnormality (CNTD)
  • usually sporadic/mutifactorial but can be associated with other anomalies
  • fetal MRI recommended
  • recurrence risk: 3%
75
Q

Other Factors Causing ONTDs

A
  • pregestational diabetes
  • valproic acid (anti-epileptic)
  • exposure to high temps
  • amniotic bands
  • VACTERL
  • T18/T13
  • single gene disorders (Meckel-Gruber, Walker-Warburg, Joubert)
76
Q

Agenesis of Corpus Callosum

A
  • structural abnormality (congenital brain anomaly)
  • failure of axons to cross midline between right and left hemispheres
  • ID/DD ranges from mild to severe
  • if not isolated, may be associated with Dandy-Walker malformation, T13, T18, T8, Aicardi syndrome, Mowat-Wilson syndrome
  • prenatal diagnosis with CMA, TORCH titers
  • recurrence risk: 2-3% if isolated
77
Q

Dandy-Walker Malformation

A
  • structural abnormality (congenital brain anomaly)
  • enlarged posterior fossa, defect in cerebellar vermis, dilation of 4th ventricle
  • associated with T13, T18, T21, Walker-Warburg, Meckel-Gruber, Aicardi, teratogens
  • prenatal diagnosis with CMA, TORCH titers
  • recurrence risk: 1-5% if isolated
78
Q

Holoprosencephaly

A
  • structural abnormality (congenital brain anomaly)
  • failed/incomplete separation of prosencephalon, craniofacial anomalies (cyclopia, anopthalmia, proboscis, CL/P; single central incisor, anosmia)
  • associated with sporadic causes, teratogens, T13, T18, triploidy, SLOS, Meckel, Kallman, SHH gene mutation
79
Q

Duodenal Atresia

A
  • structural abnormality (GI)
  • congenital absence of closure of portion of duodenal lumen leading to blockage of duodenum
  • most common neonatal intestinal obstruction
  • “double bubble”, polyhydramnios, preterm labor
  • associated with DS and other causes
80
Q

Gastroschisis

A
  • structural abnormality (GI)
  • evisceration of small and/or large bowel through abdominal wall adjacent to umbilical cord
  • typically isolated, sporadic/multifactorial, and seen when mother <20y
81
Q

Omphalocele

A
  • structural abnormality (GI)
  • abdominal wall defect with sac of amnion containing herniated abnominal viscera and/or liver into umbilical cord
  • 2/3 have other anomalies like cardiac defects and may lead to lung hypoplasia
  • associated with BWS, T13, T18
82
Q

Clubfoot (Talipes Equinovarus)

A
  • structural abnormality (skeletal)
  • abnormal relation of foot/ankle to tibia and fibula such that foot bends inward
  • male fetuses more commonly affected; bilateral more common
  • may be related to positional factors (oligohydramnios, multiple gestations, uterine abnormalities)
  • could be sign of neurological, muscular, or connective tissue, chromosomal (T18) issues
83
Q

Polydactyly

A
  • structural abnormality (skeletal)
  • postaxial: extra pinky/pinky toe
  • preaxial: extra thumb/big toe
  • more common in African Americans
  • when associated with genetic/chromosomal cause, not usually isolated
84
Q

Skeletal Dysplasia

A
  • structural abnormality (skeletal)
  • genetically heterogeneous group of >450 disorders
  • if detected in 1st or 2nd trimester, likely lethal
  • some features seen include poor mineralization, fractures, bent/bowed bones, clubfoot, absent scapula, small chest circumference
85
Q

Renal Abnormalities

A
  • structural abnormality (GU)
  • unilateral agenesis: can be associated with aneuploidy, VACTERL
  • bilateral agenesis: associated with ectopic pregnancy, Potter sequence
  • hyperechoic and isolated: associated with ARPKD, ADPKD, multicystic kidney disease
  • hyperechoic and not isolated: chromosomal, 22q11.2, infection, Meckel-Gruber, Bardet-Biedl
86
Q

Bladder/Ureter/Urethral Abnormalities

A
  • structural abnormality (GU)
  • lower urinary tract obstruction (LUTO): fetal bladder outlet obstructions including posterior urethral valves (common in males), urethral atresia (common in females)
  • uretero-pelvic junction obstruction (UPJ): most common cause of hydronephrosis, more common in males
87
Q

Gonadal Anomalies

A
  • structural abnormalities (GU)
  • includes DSDs
  • need to determine fetal chromosomes, especially if ambiguous genitalia
  • ambiguous genitalia: consider maternal history (virilization, teratogens, androgens), family history, prenatal diagnosis (SRY, CAH)
88
Q

Congenital Diaphragmatic Hernia

A
  • structural abnormality (lung/chest)
  • incomplete formation of diaphragm leading to abdominal viscera herniating into chest, pulmonary hypoplasia, pulmonary HTN
  • usually isolated but may be associated with T18, T21, Pallister-Killian, BWS
  • fetal MRI recommended
  • may need ECMO
89
Q

Cystic Adenomatoid Malformation of Lung (CCAM/CPAM)

A
  • structural abnormality (lung/chest)
  • benign hamartomatous or dysplastic lung tumor
  • sporadic, not chromosomal
  • may lead to polyhydramnios, hydrops
90
Q

Tracheoesophagela Fistula

A
  • structural abnormality (lung/chest)
  • 1+ abnormal connections between trachea and esophagus +/- esophageal atresia
  • polyhydramnios and absent stomach bubble
  • associated with VACTERL, maternal DM, T21, T18, 22q11.2, single gene disorders
91
Q

Cleft Lip/Palate

A
  • structural abnormality (face/neck)
  • most common fetal craniofacial malformation
  • CL more common in males
  • CP more common, and more common in females
  • midline cleft associated with holoprosencephaly and T13
  • best visualized with 3D/4D u/s
92
Q

Cystic Hygroma

A
  • structural abnormality (face/neck)
  • multiseptated cysts of lymphatic system due to vascular malformation
  • most commonly nuchal and may resolve in 25% of cases
  • associated with aneuploidy, cardiac anomalies, Noonan, multiple pterygium
93
Q

Pierre-Robin Anomaly

A
  • structural abnormality (face/neck)
  • sequence; mandibular hypoplasia leads to posterior displacement of tongue and u-shaped cleft palate
  • airway obstruction, repeated ear infections, natal teeth
  • keep baby in prone position, tongue-lip adhesion, mandibular bone expansion
  • associated with Stickler
94
Q

Fetal Hydrops

A
  • condition in fetus characterized by accumulation of fluid in at least two fetal compartments (skin, abdomen, scrotum/hydrocele, lungs)
  • two etiologies: immune and non-immune
95
Q

Immune Hydrops

A
  • due to Rh isoimmunization
  • Rh negative mother makes antibodies against Rh positive fetus, causing hemolytic disease of the fetus/newborn
  • usually involves D antigen but others involved as well (Lewis lives, Kell kills)
  • administration of Rhogam before procedures, before delivery at 28w GA, postpartum
  • MCA dopplers used to look at how fast blood traveling through middle cerebral artery to monitor immune reaction
  • monitored through titers
96
Q

Non-Immune Hydrops

A
  • aneuploidy (Turner, T21, T13, T18)
  • syndromes (Noonan, myotonic dystrophy, skeletal dysplasia)
  • metabolic conditions (MPS IVA, GM1 gangliosidosis)
  • infection (CMV, toxo, parvo, syphilis, herpes, rubella, coxsackie, lepto, trypanosoma cruzi)
  • alpha-thalassemia
97
Q

% Live births with birth defect or developmental disability

98
Q

% birth defects due to teratogens

99
Q

Teratogen

A

any medication, chemical, infectious disease, or environmental agent that might interfere with normal developmental of fetus and result in pregnancy loss, birth defect, or adverse outcome

100
Q

5 Factors Influencing Teratology

A
  • timing of fetal development
  • dosage
  • tissue access
  • pattern of malformation
  • genetic susceptibility
101
Q

“All or Nothing” Period

A

teratogenic exposure at 2-4 weeks GA leads to miscarriage, fetal death, or continuation of pregnancy

102
Q

Teratogen Exposure 4-10w GA

A

fetal death, major malformations (organogenesis and neural tube closure happening), growth retardation, impaired IQ

103
Q

Teratogen Exposure 10-13w GA

A

fetal death, vascular disruption, hemorrhage, tissue loss

104
Q

Teratogen Exposure in 2nd or 3rd Trimester

A

stillbirth, growth restriction, impaired IQ

105
Q

Thalidomide

A
  • used for morning sickness, leprosy treatment
  • phocomelia
  • critical exposure 34-50 days post LMP (4-10w GA); 20% exposed have affected infants
106
Q

Isotretinoin (Accutane)

A
  • vitamin A derivative; retinoid
  • CNS anomalies, ear anomalies, cardiovascular defects, thymus anomalies, ID
  • critical period 15th day following conception - end of first trimester
  • half-life of 16-20 hours and out of body in <1w
107
Q

Other Vitamin A Products

A
  • etretinate: orally active retinoid that produces similar effects as isotretinoin
  • tretinoin: topical retinoid poorly absorbed through skin
  • dietary vitamin A: metabolized to retinoids that can be teratogenic at high concentrations, not including beta-carotene
108
Q

Maternal Depression/Anxiety

A
  • untreated associated with increased risk of miscarriage, preterm delivery, low birth weight, increased fetal distress, disruptive social behavior, changes in period of sensitivity for language
  • mother at risk for postpartum depression
109
Q

Antidepressants

A
  • neonatal adaptation syndrome
110
Q

Anticonvulsants

A
  • include phenytoin, trimethadione, carbamazepine, valproate, barbiturates
  • “anticonvulsant embryopathy”: cupid’s bow lip, hypertelorism, short nose with anteverted nares, fingernail hypoplasia, meningomyelocele (ONTD); looks like FAS
111
Q

Lithium

A
  • Ebstein’s anomaly

- critical period of exposure in 1st trimester when heart valves forming

112
Q

SSRIs

A
  • increased risk of CHD (2% vs 1%)
113
Q

Benzodiazepines

A
  • possible risk for orofacial clefts
114
Q

ACE inhibitors

A
  • reduce uterine blood flow leading to decreased placental perfusion and severe fetal hypotension
  • renal tubular dysplasia leads to oligohydramnios, Potter’s sequence, and pulmonary hypoplasia; hypocalvaria
  • critical period of exposure in 2nd and 3rd trimesters
115
Q

Tetracycline

A
  • binds to calcium and leads to discoloration of teeth

- critical period 4m of pregnancy

116
Q

Warfarin

A
  • “warfarin embryopathy”: nasal hypoplasia, stippled epiphyses, limb hypoplasia
  • critical period 8-11w GA
117
Q

Fluconazole

A
  • antifungal agent used to treat mycotic infections
  • craniofacial, limb, and cardiac anomalies
  • large doses may create phenocopy of Antley-Bixler
118
Q

Methylmercury

A
  • congenital Minamata disease

- stems from eating fish high in mercury

119
Q

Radiation

A
  • threshold >5 rads imposes risk to fetus
  • may lead to miscarriage, failure to implant, IUGR, ID, microcephaly, seizures
  • critical period for ID 8-15w
120
Q

Toluene

A
  • microcephaly, ID, growth deficiency, craniofacial anomalies similar to FAS
121
Q

Varicella

A
  • varicella embryopathy: hydrops, echogenic bowel, cardiac anomalies, scarring of skin, eye abnormalities, limb underdevelopment, ID
  • 25% infection rate if mom infected and 1-3% chance of birth defects if fetus infected
  • greatest risk period 7-20w
122
Q

Zika Virus

A
  • severe microcephaly, decreased brain tissue, lissencephaly, retinal damage, hypotonia
  • infection can occur in any trimester and transmission of virus may stem from semen
  • women with potential exposure should wait 8 weeks before trying to conceive, men should wait 3 months
123
Q

CMV

A
  • petechiae (“blueberry muffin”), hearing loss, CNS problems

- primary maternal infection results in fetal infection rate of 30-40%

124
Q

Vaccines

A
  • many can have adverse effects on CNS and hematopoietic development
125
Q

Maternal Pregestational Diabetes

A
  • caudal dysgenesis, congenital heart disease, kidney problems, ONTDs
126
Q

Gestational Diabetes

A
  • macrosomia and HCM due to increased insulin output from fetus, premature birth, hypoglycemia, ONTDs
  • need to sample amniotic fluid to determine lung function
127
Q

Alcohol

A
  • no known safe level of alcohol
  • FAD: ptosis, short palpebral fissures, smooth philtrum, thin upper vermilion, cardiac defects, DD, neurobehavioral issues
128
Q

Cigarette Smoke

A
  • IUGR, preterm delivery, SIDS, orofiacial clefts, low birth weight
  • 10+ cigarettes a day leads to 7oz decrease
129
Q

Heroin

A
  • strabismus, low birth weight, respiratory distress, jaundice, SIDS, neonatal withdrawal
  • IQ not affected
130
Q

Cocaine

A
  • prematurity, IUGR, neurobehavioral problems, intracranial hemorrhage, intestinal atresia, limb reduction, urinary tract anomalies
131
Q

FDA Drug Category Update

A
  • previously A, B, C, D, X but oversimplified and didn’t take into account timing, dose, indication/maternal condition
  • letter categories removed and replaced with extensive narratives including info about pregnancy, lactation, fertility, and untreated maternal condition
132
Q

Prenatal Testing Options

A
  • initial first trimester labs: antibody screen, blood type/Rh, CBC with differential, Rubella/RPR/Varicella
  • carrier screening: CF, SMA, hemoglobin electrophoresis
  • aneuploidy screening: serum, NIPS
  • second/third timester labs: GBS, glucola
133
Q

IgM antibody

A

induced production with current infection

134
Q

IgG antibody

A

produced after IgM response

135
Q

IgG avidity

A
  • measures maturity of IgG antibody

- increases months after initial infections

136
Q

TORCH

A 
T = toxoplasmosis gondii
O = other (parvovirus, syphilis, varicella, Zika)
R = rubella
C = CMV
H = herpes
137
Q

Rubella

A
  • congenital rubella syndrome: hearing loss, vision loss, cataracts, ID, CHDs, microcephaly, IUGR, postnatal growth retardation
138
Q

Testing for Hemoglobinopathies/Prenatal anemia

A
  • CBC
  • iron binding studies
  • hemoglobin electrophoresis
  • ACOG recommends screening all pregnant women for thalassemias and hemoglobinopathies with CBC and f/u heme elec based on ancestry or low MCV/MCH
139
Q

Carrier Frequencies for Hemoglobinopathies

A
  • 1/10 African Americans for sickle cell
  • 1/7 Mediterraneans for beta thal
  • 1/20 Southeast Asians for alpha thal
  • least common in Northern European, Japanese, Native American, Inuit, and Korean ancestries
140
Q

CBC Indices

A
  • MCV: average volume of RBCs; normal MCV >80
  • MCH: average amount of Hb in RBC/sample
  • Hemoglobin level
  • RDW: variability in size of RBC; may indicate if microcytic cells present
141
Q

Hemoglobin electrophoresis

A
  • HbA: >96%
  • HbA2: 1.8-3.5%
  • HbF: <2%
  • may detect other variants like HbS (African Americans), HbC (West Africans), HbE (Southeast Asians)
142
Q

Diagnostic Prenatal Testing

A
  • goal is to determine whether specific genetic disorder present in fetus and to provide information for decision-making/pregnancy management
  • benefits: identifying conditions where prenatal treatment may be available, allowing opportunity for termination, improving neonatal outcomes
  • limitations: invasive, risk for infection, risk for miscarriage, risk for premature birth, cramping/bleeding/spotting
143
Q

CVS

A
  • performed 10-13w GA
  • placental villi obtained through transcervical or transabdominal access to placenta under u/s guidance
  • procedure-related loss: 1/200 - 1/455
  • used in conjunction with karyotype, FISH, CMA
144
Q

Amniocentesis

A
  • performed 15-20w GA or until chorion and aminon have fused
  • if completed after 22w, may not get results in time for legal termination
  • if performed after 20w risk for premature birth
  • amniotic fluid sample obtained using needle and u/s guidance
  • procedure-related loss: 1/300 - 1/500
  • used in conjunction with karyotype, FISH, CMA, CPM, AFAFP/ACHE, biochemical studies, fetal lung maturity
145
Q

Percutaneous Umbilical Blood Sampling (PUBS)

A
  • needle inserted into umbilical vein for access to fetal blood for sample collection or transfusions
  • may be used to diagnose and treat severe anemia
  • 1% loss rate
146
Q

Medication Abortion

A
  • <10w GA
  • mifepristone causes separation of trophoblast from decidua
  • misoprostol causes softening of cervix and uterine contractions
147
Q

Surgical Abortion (1st Trimester)

A
  • cervical dilation followed by procedure to empty uterus
  • manual vacuum aspiration
  • dilation and aspiration (D&C; dilation with electric vacuum)
148
Q

Surgical Abortion (2nd Trimester)

A
  • dilation and evacuation: cervical dilation, electric vacuum aspiration, forceps with disarticulation, u/s guidance
  • labor induction: administration of misoprostol/mifepristone, delivery in hospital
149
Q

Diamniotic Dichorionic

A

each twin has own placenta and amniotic sac; lambda sign on u/s

150
Q

Diamniotic Monochorionic

A

each twin has own amniotic sac but share placenta

151
Q

Monoamniotic Monochorionia

A

twins share amniotic sac and placenta

152
Q

Risks of Multiple Gestations

A
  • gestational diabetes
  • preeclamspia
  • preterm birth
153
Q

Selective Termination/Multifetal Pregnancy Reduction

A
  • performed 10-13w GA to reduce risk of pregnancy-related complications or to selectively terminate fetus with problems
  • reduction technique depends on chorionicity
  • injection of KCl if placentas separate, cord occlusion with ablation if not
154
Q

Infertility

A
  • 1+ years of unprotected intercourse without achieving pregnancy
  • affects 1/8 couples
155
Q

Causes of Infertility

A
  • male factor (35%)
  • ovulation (15%)
  • tubal pathology (35%)
  • other (5%)
  • unknown (10%)
156
Q

Male Factor Infertility

A
  • anatomic: hypospadias, obstruction of vas deferens (CBAVD), vericocele
  • endocrine: testosterone
  • genetics: chromosomal anomalies, deletions in Yq
  • other: testicular injury, surgery, heat, exposure, marijuana usage, drug usage (including chemo)
157
Q

Treatment for Male Factor Infertility

A

IUI, therapeutic donor insemination, IVF with ICSI

158
Q

Infertility d/t Ovulation

A
  • natural hormonal stimulus in hypothalamic-pituitary-ovarian axis not happening correctly
  • assessed via ovarian reserve testing
  • stress, anorexia, marathon running can shut down pathway
  • genetic etiologies include fragile X premutation, X chromosome abnormalities, PCOS, autoimmune disease
159
Q

Ovulation Treatment

A

ovulation induction (Clomid), human gonadotropins, donor egg

160
Q

Infertility d/t Tubal Pathology

A
  • pelvic inflammatory disease, septic abortion, endometriosis, ruptured appendix, tubal surgery/ectopic pregnancy
  • diagnosed via hysterosalpingogram, sonohystogram, hysteroscopy, laparoscopy
161
Q

Other Causes of Female Infertility

A

Mullerian anomalies

162
Q

Recurrent Pregnancy Loss

A

2+ failed documented clinical pregnancies or 3 consecutive pregnancy losses

163
Q

% Women experiencing miscarriage

164
Q

% Women experiencing 2 consecutive losses

165
Q

% Women experiencing 3 consecutive losses

166
Q

Causes of RPL

A
  • uterine/cervical factors (12-13%): congenital uterine anomalies, uterine fibroids, cervical incompetence
  • hormonal/metabolic: diabetes, thyroid disease, PCOS, luteal phase defect
  • immunologic factors (5-20%): antiphospholipid antibody syndrome, blood group alloimmunization, inherited thrombophilias
  • cytogenetic factors (2-5%): chromosomal rearrangement (4% of couples with RPL)
  • environment
167
Q

% Patients with RPL that experience future successful pregnancy

168
Q

Assisted Reproductive Technologies

A
  • ovulation induction
  • IUI
  • IVF
  • ovarian tissue cryopreservation
  • PGT
169
Q

Ovulation Induction

A
  • used for anovulatory infertility or unexplained infertility
  • stimulates development of follicle(s) and hCG trigger used to induce ovulation followed by timed intercourse/IUI
170
Q

IUI

A
  • used for unexplained infertility, male subfertility, failure to conceive after ovulation induction, retrograde ejaculation
  • washed sperm deposited in uterus before ovulation
171
Q

IVF

A
  • ovarian hyperstimulation, u/s-guided oocyte retrieval, insemination, fertilization, embryo culture, embryo transfer, cryopreservation of supernumerary embryos
  • fertilization may happen by allowing multiple sperm to interact with egg or through ICSI
  • 3-5 day embryos transferred may be fresh or frozen
  • risks of IVF include ovarian hyperstimulation syndrome, ovarian torsion, infection, bleeding, injury, multiple gestations, ectopic pregnancy, cost, potential risk of congenital anomalies/imprinting defects
172
Q

Ovarian Tissue Cryopreservation

A
  • used for women with cancer or at high risk of developing cancer
  • surgical tissue retrieval, cryopreservation of ovarian tissue, tissue thawed (or transplanted) and follicles allowed to grow, mature egg fertilized and embryo implanted in patient
173
Q

PGT-M

A
  • single gene/monogenic disorders
  • variant/mutation must be known so probe can be developed
  • probe development is a linkage-based test, so patient’s parents often needed to provide DNA samples
  • problem is allele drop out
  • non-disclosure PGT possible when patient does not want to know own risk status; direct method involves determining genetic status but not disclosing it and indirect method does not test genetic status of patient but uses linkage to select based on inheritance of maternal/paternal allele
  • PGT-M not feasible when unable to establish linkage, de novo mutations, genes with pseudogenes, mtDNA mutations, repeat expansions
  • PGT-M reduces but does not eliminate risk of unaffected pregnancy
174
Q

PGT-HLA

A
  • HLA matching for bone marrow transplant (like in Fanconi anemia)
  • only full sibs have potential to be exact matches
175
Q

PGT-SR

A
  • structural rearrangements like translocations, inversions
  • most commonly done to identify balanced embryos for transfer
  • testing techniques same as for PGT-A
176
Q

PGT-A

A
  • aneuploidy

- largely run on NGS platform and enables single embryo transfer, high live birth rates, low multiple gestation rates

177
Q

Benefits of PGT

A
  • for couples at high risk of sex-linked disorders, aneuploidy, and single gene defects
  • avoid decision regarding termination
  • possibly improve success rates of IVF by not transferring abnormal embryos
178
Q

Limitations of PGT

A
  • technical expertise required
  • cost
  • doesn’t obviate need for invasive prenatal testing
  • what conditions are acceptable?

Genetic Counseling Boards (22 decks)

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