Prenatal Testing Flashcards
what 11 things must you test/screen for in a PG mom throughout the course of her pregnancy?
ABO Rh and Ab screen Hct or Hgb and MCV cervical cytology rubella immunity syphilis testing HBV surface antigen screening GC/CT screening thyroid fxn testing HIV urine culture Down Syndrome
why do you need to test ABO Rh and Ab’s
need to know baby’s blood type and mom’s Rh type along with baby’s b/c if mom has ab’s to baby could cause hemolytic dz of the newborn
why are hct, hgb and MCV important to know?
can indicate anemia (IDA and pernicious anemia) or thallasemia
are PAPs a routine part of prenatal exams?
NO but can get one if due for a PAP
what are the screening recommendations for PAP screens (how often)? (USPSTF, ACS, ACOG)
varies on the resource you consult
USPSTF at least every 3 yrs
ACS annual screening (biennial if liquid-based)
ACOG biennial for women
what are 4 high risk groups that will require more frequent PAPs/screening?
HIV infected
immunosuppressed
in utero DES exposure
ACOG recommends annual screening for women who have been treated in the past for CIN2, CIN3 or cervical CA
if CIN 2 or 3 is found on a PAP during PG do you treat it?
no b/c most likely will regress in post partum period
monitor w/colposcopy w/o endocervical curettage once per trimester
post partum evaluation= colposcopy and cervical cytology at 6 and 12 weeks PP
if mom tests (+) for rubella infxn during PG what is the recommended course of action?
TAB esp if
if a PG mom is not immune to rubella what is the course of action?
counsel and administer PP immunization
what other vaccine does the CDC and ACOG recommend in conjuncture with rubella in vulnerable women?
MMR
why do we test for syphilis in PG mom’s?
to prevent perinatal transmission of treponema pallidum
tx appropriately w/(+) test result
why do we test for HBVsAg?
to prevent perinatal transmission
what can GC/CT cause in the infant? how is it transmitted? when do you screen for GC/CT? what kind of test is it?
can cause conjunctivitis or pneumonia in the infant
transmitted most commonly through birth canal but can happen w/C-section also
screen at 1st PN
NAAT test: endocervix or vaginal swab but urine testing appears to be as sensitive as swabs
what at risk populations are recommended to undergo thyroid function testing?
symptomatic women personal or family hx of thyroid problems DM Type 1 head or neck radiation hx goiter amiodarone use lithium use iodine deficiency
what is the universal screening recommendation for thyroid function testing?
still recommended by some so as to not miss those w/o risk factors or asx women
untreated thyroid dz can result in what?
fetal neurological abn
PG women w/Thyroid peroxidase antibodies are how much more likely to have SABs? preterm birth risk? what other risk factors are assoc with a TPA (+) mom?
2-3 x’s higher if have (+) TPA
preterm birth risk doubled
perinatal mortality
LGA infants
for a woman with hypothyroidism, T4 can increase the risk of what? what can some TPA (+) develop as dz processes? untreated women with elevated TPA should have their TSA checked how often?
tx w/T4 can increase risk of SAB and preterm delivery
TPA (+) women can develop (subclinical) hypothyroidism
untx women w/elevated TPA should have TSH checked monthly in 1st half of PG and then at least once during 3rd trimester
how much can iodine levels be decreased in PG?
as much as 40% dt increased urinary excretion
is HIV testing an “opt-in” or “opt-out” test?
opt-out now
what are 4 advantages of universal HIV testing now?
PG termination option earlier (at all)
medical management
prevention of transmission and identification of infected partners
PN tx
what is the transmission rate w/and w/o tx of HIV in PG?
w/o intervention transmission is 15-40%
w/retroviral tx transmission is reduced to 2% along with avoiding breastfeeding and labor
when would you re-test for HIV and why?
in the 3rd trimester
for women at increased risk of infxn
areas of high HIV infxn
women who declined testing earlier in PG
why do a urine culture?
to dx asx bacterial infxns
PG women w/untreated bacteriuria are at an increased risk of what 3 things?
pyelonephritis
premature labor
low birth weight infants
if a urine test comes back (+) for bacteria what do you do?
retest 1 wk after tx
monthly testing until delivery (for those whose culture showed asx bacteriuria)
women w/increased risk of asx bacteriuria (sickle cell trait, urinary tract abn, diabetics)
can treat w/standard medical tx, naturopathic tx
what to do if GBS is (+)?
tx if present, even if minimal growth on culture!
prophylactic tx in labor
what is ACOGs recommendations for Downs screening?
all women are offered aneuploidy screening
what 5 tests are there to test for Down’s?
first trimester combined test integrated tests (full integrated, serum integrated, sequential and contingent) quadruple test genetic sonogram new DNA test
what test is best for women who desire early dx and privacy?
first trimester combined test
how is a first trimester combined test done? management w/a (+) test? disadvantages?
U/S for nuchal transnuchal and gestational age by crown-rump length along with serum pregnancy associated plasma protein-A (PAPP-A) and free or total human chorionic gonadotropin (b-hCG) management for (+)= chorionic villi sampling disadvantages: CVS carries more risk of PG loss than amniocentesis, does not screen for open neural tube defects
what do integrated tests measure w/or w/o in what trimesters? what are the 3 integrated tests?
measures analytes w/or w/o US in 1st and 2nd trimesters
full integrated test
serum integrated test
sequential and contingent testing
full integrated test has what rate of down syndrome detection (high or low)? what is being measured at what week range? what serum marker?
highest detection rate for Down’s syndrome
U/S measurement of NT at 10-13 wks
PAPP-A at 10-13 wks
quadruple test at 15-18 wks (AFP, unconjugated E3, hCG, inhibin A)
the serum integrated test is the same as the full integrated test minus what procedure? why would you use this one?
U/S measurement of NT
use for women in areas where they do not have access to technicians who can adequately measure NT
sequential and contingent testing give results faster or more slowly?
faster, sooner than the 2nd trimester
stepwise sequential testing involves what? how does management vary for women of high vs low risk?
1st trimester portion of integrated testing
offer CVS to women at high risk
if normal risk perform in the 2nd trimester
what are the 3 risk cut-offs for contingent testing?
very high risk for Down’s after 1st trimester testing- immediate invasive PN dx
low risk for Down’s are given their risk estimate and have no further testing
women w/intermediate testing get 2nd trimester marker testing and integrate all testing data
quadruple test measures the serum level of what 4 markers? with whom do you use this test? during what weeks?
serum AFP, uE3, inhibin A, hCG
use w/women who began PN care in 2nd trimester
do b/w wks 15-18
why would you do a genetic sonogram? is it as useful as primary screening?
for late timing (late to getting PNs), wks 18-20
not as useful
what is the new DNA testing method? is it approved as a screening test?
test of maternal plasma DNA
not yet approved as a screening test; does not dx other chromosomal defects, will be an accurate test once it is approved for use
for a mom who tests (-) for Down’s syndrome markers what does this mean? (2-fold)
means risk is less than cut-off
does NOT rule out Down’s syndrome infant
for a mom who tests (+) what does this mean? what would you suggest? (3 fold)
means risk is higher than cut off level
suggest meeting w/genetic counselor
offer fetal karyotype testing (CVS in 1st trimester, amniocentesis in 2nd)
offer pts resources to help them make informed decisions (decision to maintain, end or adopt out; resources to raise a Down’s child)
specifically, in at risk women, what 10 tests do you need to do? (aside from the normal)
gonorrhea thyroid dz TB toxoplasmosis HCV ab's varicella bacterial vaginosis herpes simplex virus chagas dz lead level screening
what are the CDC recommendations for screening for gonorrhea?
women aged 15-24 yo
increased risk for gonorrheal infxn or other STD
new or multiple sex partners
inconsistent condom use
those who engage in commercial sex work
those who live in communities w/high prevalence of dz
is congenital TB common or rare?
rare
test at risk populations
transmission routes of toxoplasmosis?
environmental exposure (litter boxes) undercooked meat from infected animals
CDC recommendations for HCV testing?
ever injected illegal drugs received clotting factors made before '87 received blood/organs before july '92 were every on chronic hemodialysis have evidence of liver dz (elevated ALT) are infected w/HIV
if a woman is not immune and exposed to varicella during PG what is the protocol?
administer varicella immune globulin product, VariZIG prophylaxis and immunize after pregnancy
cause of BV? risk factors? is screening recommended?
caused by reduction of lactobacillus= anaerobic (-) rods can flourish
risk factors: sexual activity, douching, cigarette smoking
screening not recommended in routine PN care
is trich recommended as a routine part of PN care?
NO
is routine HSV testing indicated in asx women?
no but can be reasonable to test if partner is (+) even if woman is asx
what is Chagas dz?
parasitic dz endemic to Latin America, can be asx but can also be transmitted to the fetus
who should you consider screening for lead? dx of >5 mgc/dL?
recent immigrants where ambient lead levels were high resides near high lead sources pica occupational exposure environmental exposure use of lead containing cosmetics use of lead glazed pottery some Chinese and Ayurvedic medicines dx: lead levels >5 mcg/dL need follow up dependent on how much above, but pediatrician should be told of mother's lead levels at birth
can lead cross the placenta? what are high lead levels associated with?
yes it crosses the placenta
can be assoc w/miscarriage and still-birth
breastmilk will also need to be evaluated before breast feeding
what test do you do to test for thallasemias and hemoglobinopathies?
red cell indicies
what other test can you do specifically for hemoglobinopathies?
hemoglobin electrophoresis
what special population do you always need to test for heritable disorders?
Ashkenazi Jews
just because you get a (-) CF test does that mean the baby is 100% in the clear of having CF?
NO, it means the infant is only free of the CF mutations we know of currently
what procedure can be useful to determine EDD?
U/S in early PG
1st trimester U/S can detect fetal malformations and multiple PGs earlier
what 7 tests/procedures are done during the 2nd and 3rd trimesters?
NTD screening and Down's syndrome screening gestational diabetes STDs CBC and Ab screening GBS screening U/S
when is a PG mom screened for gestational diabetes? when would you consider screening in the 1st trimester?
24-28 wks gestation
consider screening in the 1st trimester if mom is obese, previous hx of GD, previous macrosomia
when does the CDC recommend screening again for STDs? what test should you re-do in mom’s 25 and younger? in certain areas what two other STDs will you test for?
repeat testing at 28-36 wks in women w/prior PN dx of STD or continued risk factors
CDC recommends retesting chlamydia in mom’s 25 and younger
in some areas repeat syphilis and HIV testing
when do you repeat a CBC and Rh ab screen?
3rd trimester for anemia
repeat Rh screening in unsensitized Rh (-) women and administer Rhogam if have a rxn
when should all women be screened for GBS? what two populations will you treat w/intrapartum antibiotic prophylaxis regardless of GBS colonization?
35-37 wks test for GBS
tx prophylactically: women who previously birthed an infant w/invasive GBS dz or women w/GBS bacteriuria in current PG
what do 2nd and 3rd trimester U/Ss look for?
presence or absence of fetal cardiac activity cardiac rate and rhythm fetal number fetal presentation assessment of amniotic fluid volume placental appearance and location fetal biometry evaluation of uterus, cervix, adnexa when clinically appropriate fetal anatomic survey
what are you looking for specifically in a 3rd trimester U/S?
IUGRs
what is the biophysical profile to assess fetal well-being seen on an U/S?
fetal movement fetal tone fetal breathing amniotic fluid volume results of non-stress testing
