Final study guide Flashcards
G in G0P0000
gravidity - how many pregnancies
T in TPAL
Term deliveries, greater or equal to 37 weeks; twins count as one
P in TPAL
preterm deliveries (20 to 36-6/7 weeks); twins count as one
A in TPAL
abortions, miscarriages, or terminations prior to 20 weeks
L in TPAL
living children
Valproic acid
spina bifida (most common), ASD, cleft palate, hypospadias, polydactyly, craniosynostosis
Maternal PKU
CHD, microcephaly, low birth weight/slow growth, ID
Maternal diabetes
spontaneous abortion, stillborn, increases birth defects by 300% (CHD, caudal regression/sacral agenesis, open neural tube defects, hypoplastic femurs, renal abnormalities)
Alcohol
growth restriction, FASD, change in the structure or functioning of the CNS. characteristic facial features.
Accutane
major malformations and high rate of mental retardation
TORCH infections
TORCH - toxoplasma gondii, other agents, rubella, cytomegalovirus (CMV), and herpes simplex virus (HSV). May cause miscarriage, stillbirth, IUGR, microcephaly, lethargy, hearing loss, and CHD.
Mercury
brain damage, hearing & vision problems
Caffeine
typically thought to cause IUGR and preterm delivery, but recent studies have refuted this. Increased risk of fetal death.
Radiation
stunted growth, deformities, abnormal brain function, or cancer.
Warfarin
Inhibits vitamin K; skeletal abnormalities, rhizomelia, nose malformations, prominent forehead and flat face, rhizomelia, club foot, brachydactyly, nail dysplasia, CNS structural defects, eye defects, IUGR
Thalidomide
limb defects
Illegal substance use
cocaine: strokes, SGA, microcephaly, prematurity
marijuana: no assoc. with growth and morphology, generally no affect on miscarriage rates and apgar scores, but a study found heavy users may have shortened gestation time.
meth: dopamine response, strokes, SGA, microcephaly, prematurity
“All or nothing” concept
Embryonic exposure that happens before organogenesis results in either no adverse embryonic outcome or in embryonic death.
When in pregnancy is the baby most susceptible from effects of teratogens?
In general, during the first trimester fetuses are most susceptible to malformations, 2nd and 3rd trimester are more susceptible to IQ effects. 3-8 weeks greatest sensitivity.
what are the risk factors for developing gestational diabetes?
severe obesity, strong family history of type 2 diabetes, previous history of GDM, impaired glucose metabolism
How common are complications of pregnancy? (gestational diabetes, preterm labor, preeclampsia)
11.4% of live births nationwide are preterm (Oklahoma is a little higher), hypertensive disorders complicate 5-10% of all pregnancies, gestational diabetes affects 4.2% of pregnacies
Which conditions have specific guidelines around carrier screening?
SMA, CF, hemoglobinopathies, fragile X, tay sachs
Which recessive conditions have a higher prevalence in Ashkenazi Jewish pop?
tay-sachs, canavan disease, familial dysautonomia
What is the criteria for an ideal screening test/program?
- Disorder is clinically severe
- High frequency of carriers in the screened population
- Availability of a reliable test with a high specificity and sensitivity
- Availability of prenatal diagnosis
- Access to genetic counseling
What are birth defects that are more commonly seen/may warrant involvement of a genetic counselor?
cystic hygroma, duodenal atresia, omphalocele, multicystic kidney, hydrocephalus
How are most birth defects inherited?
Multifactorial inheritance, some may be associated with certain genetic conditions
What are some diagnostic options for pregnancy and when can they be performed?
CVS - 10-13 weeks
Amniocentesis - 15+ weeks
What are some risks that come along with an invasive test?
Risks of CVS: pregnancy loss (1/300), bleeding (higher risk in transcervical vs transabdominal - 32%); culture failure, amniotic fluid leakage, or infection <0.5%; limb-reduction defects 6:10,000
Risks of amnio: pregnancy loss (1/500); transient vaginal spotting or amniotic fluid leakage (1-2%); needle injury to fetus (rare); amniotic fluid cell culture failure (0.1%)
What are the advantages and limitations of CVS?
Advantages: can be performed earlier in pregnancy than amnio, viable cells from procedure allow for shorter specimen processing time, earlier results/diagnosis can allow for earlier decision making/managing
Limitations: longer learning curve for trainees, risk for confined placental mosaicism - may need follow-up testing
What are the advantages and limitations of amnio?
advantages: no risk for confined placental mosaicism if passage through placenta is avoided, sample can also be used for AFP testing and TORCH testing
Limitations: early amnio not recommended, patients advised to wait until 15-16 weeks until procedure and even longer for results, risk of maternal cell contamination
When is the appropriate gestational window for elective abortions?
Up to 21 weeks
What is cfDNA screening/NIPT?
Blood screen that looks at the ratio of naturally occurring fetal DNA present in the mother’s blood to look for common aneuploidies (13, 18, 21, sex chromosomes)
When and who should cfDNA screening be offered to?
any woman can be offered it past 10 weeks gestational, but its recommended for high risk pregnancies (AMA and isolated soft ultrasound markers)
Limitations of NIPT/cfDNA
only validated for common aneuploidies, non diagnostic, limited validation for twin+ pregnancies, possible false positives due to placental mosaicism, demise of co-twin, maternal karyo abnormalities, maternal neoplasm, maternal obesity, and organ transplants. Does not test for neural tube defects.
Conditions on NBS should be
well defined, accurate screening and diagnostic test available, early intervention or treatment available, results are actionable
When is NBS conducted
automatically after birth at a hospital or home birth. Personal exemption form has to be filled out if parents dont want it.
Is NBS screening or diagnostic?
screening
What is the turn around time for NBS?
Collection within 24 to 48 hrs of birth, abnormal results callout within a few days of collection
Sensitivity/specificity of NBS
false positive rate low, PPV high
Limitations of NBS
barriers to intervention, non-diagnostic
How many conditions on Oklahoma NBS
58
According to ACOG, all women who are pregnant or thinking about getting pregnant should be offered carrier screening for -
cystic fibrosis, hemoglobinopathies, SMA
Targeted carrier screening
testing for disorders based on family history and ethnicity
Expanded carrier screening
multiple disorders screened in a single test, regardless of ethnicity. Carrier panels vary between companies, some test for more than 100 conditions.
ACOG recommended basic carrier screen for all ethnicities include
cystic fibrosis, SMA, and fragile X
ACOG recommended basic carrier screen for african americans includes
thalaessemia and sickle cell disease
ACOG recommended basic carrier screen for southeast asian or mediterranean includes
thalassemia
ACOG recommended basic carrier screen for french canadian/cajun/creole include
tay-sachs
ACOG recommended basic carrier screen for jewish include
cystic fibrosis, tay-sachs, canavan, and familial dysautonomia
What is a quad screen?
a blood test that looks for alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin, and inhibin-A. The screening test then looks for T21, T18, and neural tube defects
High AFP assoc with
neural tube defect, wall anomaly, multiple fetuses, pregnancy is further along
Low AFP associated with
down syndrome
low unconjugated estriol assoc with
down syndrome
High human chorionic gonadrotropin assoc with
down syndrome
High inhibin-A assoc with
down syndrome
When is a quad screen offered?
Can be combined with the first trimester screening test at the 9th-13th week blood draw, and the 11th-13th week ultrasound. can be done on its own during the 15-20th week of pregnancy.
Turn around time for quad screen
4-5 days
Limitations of quad screen
not diagnostic, screens only for common birth defects, 10-20% of defects are missed, false positive rate
