ABGC BOARDS STUDY GUIDE 2025/2026 QUESTIONS WITH
ANSWERS GRADED A+
✔✔Trisomy 13/18 1st Trimester Pregnancy Screen - ✔✔low hCG, low PAPP-A, low
AFP + increased NT
✔✔Down Syndrome 2nd Trimester Quad screen? - ✔✔high hCG, high inhibin A, low
uE3, low AFP
✔✔Trisomy 18 2nd trimester quad screen - ✔✔low hCG, low inhibin A, low uE3, low
AFP
✔✔Steroid sulfatase deficiency/Smith-Lemli-Opitz/x-linked ichthyosis - ✔✔low uE3
✔✔Nuchal translucency - ✔✔fluid between tissue and skin along fetal neck
Abnormal >3 - 3.5 mm at 11-14 wks
Correct gestational age is critical because NT measurements change over pregnancy
Risk for:
Chromosomal abnormality (30-40%)
Heart defect
Single gene disorders - Noonan, lethal skeletal dysplasias
Micro del/dups
✔✔Cystic hygroma - ✔✔single or multiple cysts of lymphatic system, generally in
neck/back region
Severe cases lead to hydrops
Risk for:
Chromosome abnormality (60%) - Down syndrome, Turner
Heart defect
Micro del/dups
✔✔Hydrops - ✔✔generalized skin edema, pericardial, pleural effusions, ascites - fluid in
3+ organs
Mortality ~90%
Risk for:
Chromosome abnormality (16%)
Micro del/dups
Other: CMV, infections, Rh incompatibility, metabolic disorders, heart defects
✔✔Ventriculomegaly - ✔✔enlargement of cerebral ventricles (>10 mm)
May develop hydrocephalus in severely dilated cases
X-linked hydrocephalus - L1CAM: hydrocephalus d/t aqueductal stenosis, possible
agenesis of the corpus callosum, macrocephaly, spasticity, ID, thumb adduction
Risk for:
Chromosome abnormality (2% isolated, 17% if additional anomalies)
,Micro del/dups
Other: infection (CMV) many genetic syndromes
✔✔Holoprosencephaly - ✔✔failure of developing forebrain to divide into two separate
hemispheres and ventricles - associated with craniofacial, CNS, cardiac anomalies
Risk for:
Chromosome abnormalities (25-50%) - T13
Single gene disorders (18-25%)
Micro del/dups
✔✔Diaphragmatic hernia - ✔✔some portion of abdomen protrudes into the chest cavity
1/5000
Fetal demise not uncommon - depends on how much lung tissue has been able to
develop
Risk for:
Chromosomal abnormality risk low if isolated, 30% if additional anomalies
Micro del/dups
✔✔Omphalocele - ✔✔transparent sac of amnion at cord insertion containing abdominal
contents
50% risk for other anomalies
Chromosomal abnormality (30-60%) right sided - Beckwith-Wiedemann syndrome
✔✔Gastrochisis - ✔✔small or large bowel free floating in abdomen (often right-sided)
1/4000 typically isolated
Associated with elevated MSAFP
✔✔Echogenic bowel - ✔✔increased risk for DS, CF and infection
✔✔Choroid plexus cysts - ✔✔increased T18 risk
>90% resolve, cysts themselves are not harmful
✔✔Sickle Cell Carrier Frequency AA - ✔✔1:12
✔✔Tay Sachs Carrier Frequency AJ - ✔✔1:30
✔✔Cystic Fibrosis Carrier Frequency - ✔✔1:25
✔✔Thalidomide - ✔✔first recognized teratogen; used as anti-nausea in 1950s
Effects: phocomelia (hands and feet attached to abbreviated arms and legs), CHD,
microtia, deafness, eye anomalies, oral clefts, GU issues, ID
Critical window: ED 34-50
✔✔Warfarin - ✔✔nasal hypoplasia, stippled epiphyses, limb hypoplasia
Critical window: 6-9 weeks
, ✔✔ACE inhibitor - ✔✔renal tubular acidosis → potter sequence, IUGR
✔✔Anticonvulsants (valproic acid) - ✔✔NTDs (meningomyelocele), nail hypoplasia,
long philtrum, short nose
Seizures in mom can lead to hypoxia
✔✔Radiation - ✔✔> 5 rads: microcephaly, ID, seizures, growth restrictions, eye
anomalies
✔✔Maternal diabetes - ✔✔1st trimester critical window
HbA1C - good indicator of glucose over 3 month period
Very poor control = >10, 10-15% anomaly risk
Associated anomalies:
CNS: NTDs, caudal regression
Cardiac: VSD, ASD, coarctation of the aorta, transposition of the great arteries
Renal anomalies: GI anomalies
Gestational DM - no malformations, macrosomia babies with poor glucose regulation
✔✔Maternal PKU - ✔✔goal Phe level of below 6
Associated anomalies: IUGR, DD/ID, cardiac, behavior, and characteristic facies similar
to FAS
✔✔CMV - ✔✔40% transmission with primary infection
10-15% will show: deafness, growth restriction, microcephaly, cerebral calcifications,
ocular abnormalities, hepatosplenomegaly
✔✔Rubella - ✔✔1st trimester - 4th month critical window
Cataracts, CHD, IUGR, microcephaly, seizures, rash
~1% theoretical risk with vaccine
✔✔Toxoplasmosis - ✔✔parasite found in uncooked meat, cat feces, soil
Chorioretinitis, pneumonia, rash, long term - ID, seizures, deafness/blindness
Increased risk for transmission with increasing gestational age, but decreased symptom
severity
Life long immunity
✔✔Fetal alcohol syndrome - ✔✔growth restriction, low IQ, behavioral issues, short
palpebral fissures, smooth philtrum, thin upper lip
✔✔Down Syndrome (47, XY/XX. +21) - ✔✔1:700 live births
Most common chromosomal abnormality in newborns
75% conceptuses result in SAB
Causes:
95% dt extra chromosome 21
ANSWERS GRADED A+
✔✔Trisomy 13/18 1st Trimester Pregnancy Screen - ✔✔low hCG, low PAPP-A, low
AFP + increased NT
✔✔Down Syndrome 2nd Trimester Quad screen? - ✔✔high hCG, high inhibin A, low
uE3, low AFP
✔✔Trisomy 18 2nd trimester quad screen - ✔✔low hCG, low inhibin A, low uE3, low
AFP
✔✔Steroid sulfatase deficiency/Smith-Lemli-Opitz/x-linked ichthyosis - ✔✔low uE3
✔✔Nuchal translucency - ✔✔fluid between tissue and skin along fetal neck
Abnormal >3 - 3.5 mm at 11-14 wks
Correct gestational age is critical because NT measurements change over pregnancy
Risk for:
Chromosomal abnormality (30-40%)
Heart defect
Single gene disorders - Noonan, lethal skeletal dysplasias
Micro del/dups
✔✔Cystic hygroma - ✔✔single or multiple cysts of lymphatic system, generally in
neck/back region
Severe cases lead to hydrops
Risk for:
Chromosome abnormality (60%) - Down syndrome, Turner
Heart defect
Micro del/dups
✔✔Hydrops - ✔✔generalized skin edema, pericardial, pleural effusions, ascites - fluid in
3+ organs
Mortality ~90%
Risk for:
Chromosome abnormality (16%)
Micro del/dups
Other: CMV, infections, Rh incompatibility, metabolic disorders, heart defects
✔✔Ventriculomegaly - ✔✔enlargement of cerebral ventricles (>10 mm)
May develop hydrocephalus in severely dilated cases
X-linked hydrocephalus - L1CAM: hydrocephalus d/t aqueductal stenosis, possible
agenesis of the corpus callosum, macrocephaly, spasticity, ID, thumb adduction
Risk for:
Chromosome abnormality (2% isolated, 17% if additional anomalies)
,Micro del/dups
Other: infection (CMV) many genetic syndromes
✔✔Holoprosencephaly - ✔✔failure of developing forebrain to divide into two separate
hemispheres and ventricles - associated with craniofacial, CNS, cardiac anomalies
Risk for:
Chromosome abnormalities (25-50%) - T13
Single gene disorders (18-25%)
Micro del/dups
✔✔Diaphragmatic hernia - ✔✔some portion of abdomen protrudes into the chest cavity
1/5000
Fetal demise not uncommon - depends on how much lung tissue has been able to
develop
Risk for:
Chromosomal abnormality risk low if isolated, 30% if additional anomalies
Micro del/dups
✔✔Omphalocele - ✔✔transparent sac of amnion at cord insertion containing abdominal
contents
50% risk for other anomalies
Chromosomal abnormality (30-60%) right sided - Beckwith-Wiedemann syndrome
✔✔Gastrochisis - ✔✔small or large bowel free floating in abdomen (often right-sided)
1/4000 typically isolated
Associated with elevated MSAFP
✔✔Echogenic bowel - ✔✔increased risk for DS, CF and infection
✔✔Choroid plexus cysts - ✔✔increased T18 risk
>90% resolve, cysts themselves are not harmful
✔✔Sickle Cell Carrier Frequency AA - ✔✔1:12
✔✔Tay Sachs Carrier Frequency AJ - ✔✔1:30
✔✔Cystic Fibrosis Carrier Frequency - ✔✔1:25
✔✔Thalidomide - ✔✔first recognized teratogen; used as anti-nausea in 1950s
Effects: phocomelia (hands and feet attached to abbreviated arms and legs), CHD,
microtia, deafness, eye anomalies, oral clefts, GU issues, ID
Critical window: ED 34-50
✔✔Warfarin - ✔✔nasal hypoplasia, stippled epiphyses, limb hypoplasia
Critical window: 6-9 weeks
, ✔✔ACE inhibitor - ✔✔renal tubular acidosis → potter sequence, IUGR
✔✔Anticonvulsants (valproic acid) - ✔✔NTDs (meningomyelocele), nail hypoplasia,
long philtrum, short nose
Seizures in mom can lead to hypoxia
✔✔Radiation - ✔✔> 5 rads: microcephaly, ID, seizures, growth restrictions, eye
anomalies
✔✔Maternal diabetes - ✔✔1st trimester critical window
HbA1C - good indicator of glucose over 3 month period
Very poor control = >10, 10-15% anomaly risk
Associated anomalies:
CNS: NTDs, caudal regression
Cardiac: VSD, ASD, coarctation of the aorta, transposition of the great arteries
Renal anomalies: GI anomalies
Gestational DM - no malformations, macrosomia babies with poor glucose regulation
✔✔Maternal PKU - ✔✔goal Phe level of below 6
Associated anomalies: IUGR, DD/ID, cardiac, behavior, and characteristic facies similar
to FAS
✔✔CMV - ✔✔40% transmission with primary infection
10-15% will show: deafness, growth restriction, microcephaly, cerebral calcifications,
ocular abnormalities, hepatosplenomegaly
✔✔Rubella - ✔✔1st trimester - 4th month critical window
Cataracts, CHD, IUGR, microcephaly, seizures, rash
~1% theoretical risk with vaccine
✔✔Toxoplasmosis - ✔✔parasite found in uncooked meat, cat feces, soil
Chorioretinitis, pneumonia, rash, long term - ID, seizures, deafness/blindness
Increased risk for transmission with increasing gestational age, but decreased symptom
severity
Life long immunity
✔✔Fetal alcohol syndrome - ✔✔growth restriction, low IQ, behavioral issues, short
palpebral fissures, smooth philtrum, thin upper lip
✔✔Down Syndrome (47, XY/XX. +21) - ✔✔1:700 live births
Most common chromosomal abnormality in newborns
75% conceptuses result in SAB
Causes:
95% dt extra chromosome 21
