Preconception Care, Prenatal Counseling, Teratology and Prenatal Diagnosis -Castro Flashcards
Who is generally responsible for preconception care? What are common issuers to address?
the primary care provider
family planning, weight, nutrition and exercise, substance use, medications, screen for infections/immunize
How much folic acid is recommended for a normal woman? for a patient with an increased risk for neural tube defects?
normal: 300 mcg/day preconception through pregnancy
increased risk: 4 mg/day 1 month preconception and in 1st trimester then decrease to 400mcg/day later
If a woman is not vaccinated against Rubella, when should the vaccine be given?
3 months before pregnancy
What are some class D medications that should be avoided during pregnancy?
ACE Inhibitors
tetracycline
coumadin
What are some class X medications that should be avoided during pregnancy?
valproid acid and accutane
What are the different categories of medications: A, B, C, D, X?
A=no risk in human studies
B=no evidence of risk in studies
C=Risk cannot be ruled out (animal studies show adverse effects on fetus or no studies in animals or women)
D=human risk. Only use if benefits outweigh risks
X=do NOT use in preggos
What are the target goals for pre gestational diabetes (Hgb A1c, FBS, PPBS)? When is the ideal time to control diabetes?
Hgb A1C < 6.5
FBS (fetal blood sugar): 70-90
1 hour PPBS (post prandial (after eating) blood sugar): 100-130
control BEFORE pregnant
What are the potential diagnostic methods used after a positive abnormal prenatal screening?
invasive testing (CVS, Amniocentesis, Cordocentesis) (all corey some risk of fetal loss)
high resolution fetal ultrasound
Non-invasive testing for cell free fetal DNA in maternal blood
What is genetic counseling?
non-directive
involves:
- educating patient re: screening vs. diagnostic testing
- discussing potential risks and benefits of testing
- information about conditions tested for
- information on options
What prenatal diagnosis is offered to all women?
diagnosis for aneuploidy
What are some common carrier screening tests used to detect asymptomatic carriers?
Cystic fibrosis: DNA based. Defective chloride channels. 1/25 Caucasions
Tay Sachs: Enzyme or DNA. Hexosaminidase A deficiency (Ashkenazi Jews and French Canadians)
Canavan disease: DNA
Alpha Thalassemia: MCV
Beta Thalassemia: MCV and Hgb
Sickle Cell Disease: Hgb. defective gene for beta chain. 1/10 African Americans
If a pregnant woman tests positive for a carrier screening, what is your next step?
Offer partner testing and/or prenatal diagnosis
What is Fragile X Syndrome?
X-linked, look for # triplet repeats on long arm of X chromosome.
most common inherited form of disability
screen women with premature ovarian failure, and individuals with autism or low IQ of unknown cause
What does increased maternal age put a fetus at risk of? Is paternal age also associated with this?
aneuploidies
normally from meiotic nondisjunction
Paternal age is not associated with aneuploidies but is associated with skeletal dysplasias
What is the first trimester screening? At what gestational age should this be done? What should be offered with a positive screening?
US for fetal NT (nuchal translucency)
serum free beta hcg
9-13 weeks GA
offer CVS diagnosis or 2nd trimester screen
What does the second trimester serum screening include? When is this done? What should be offered when there is a + screen?
AFP, estriol, Beta hcg and inhibin A (quadruple test)
15-18 weeks (can be offered to women that missed the first trimester screen)
+ test==> offer diagnostic amniocentesis
What can an elevated AFP in the 2nd trimester screen indicate?
open neural tube defects
Which screening test provides 95% detection for T-21 with only a 5% false positive rate?
Integrative screening (combines first and second trimester tests)
What are some characteristics of Trisomy 21?
(Down syndrome):
- short stature
- classic facies
- developmental delay
- IQ 40-90
- can be assoc with other anomalies (duodenal atresia, cardiac)
What are some characteristics of Trisomy 18?
(Edward’s Syndrome):
- severe growth restriction and multiple congenital anomalies.
- Clenched fist
- overlapping digits
- rocker bottom feet.
- May have: cardiac defects, omphalocele, NTD’s.
- Most die by age 2.
What are some characteristics of Trisomy 13?
(Patau’s syndrome):
- growth restriction with multiple anomalies—often midline defects of brain and face such as holoprosencephaly, cleft palate, proboscis
- club feet
- polydactyly
- omphalocele
- Usually don’t live past first year of life.
What does an elevated 2nd trimester serum AFP screen for? What are the most common types? What tests confirms a diagnosis?
open neural tube defects
anencephaly, spina bifida (myelomeningocele), encephalocele
diagnosis confirmed by fetal ultrasound with or without amniocentesis for amniotic fluid AFP/acetylcholinesterase
What are some other causes of elevated AFP?
- fetal abdominal wall defects (gastroschisis, omphalocele) (gut makes AFP –> more into the maternal flow)
- placental abruption
- fetal demise
- multiple gestation
- wrong gestational age
What is a teratogen? What are the most common ones? When is it most important to avoid these?
anything that causes a birth defect in the exposed fetus—includes anatomic abnormalities, growth abnormalities, fetal loss, mental or developmental abnormalities
Historical teratogens: thalidomide (phocomelia), and DES (vaginal adenocarcinoma), alcohol, tobacco, cocaine, meth, warfarin, anti-HTN meds, chemo agents, radiation, isotretinoin, dilantin, valproic acid, phenobarbitol,
most important in the first trimester*
What are some signs of Fetal Alcohol Syndrome? What is a safe amount of alcohol in pregnancy?
- microcephaly,
- IUGR or post-natal growth deficiency
- midfacial defects (short palpebral fissures, short nose, thin vermillion border, hypoplastic philtrum, possible cleft lip/palate)
- possible cardiac defect
*no alcohol has been proven to be safe
What can coumadin cause in a fetus? What can be used in pregnant women instead?
- fetal loss
- IUGR
- postnatal growth deficiencies/skeletal dysplasia
- craniofacial anomalies
- crosses placenta
- can cause fetal hemorrhage
*heparin/lovenox does NOT cross the placenta
What fetal problems can valproic acid cause?
facial dysmorphisms
neural tube defects
