Midterm- prenatal testing Flashcards
ABO Rh and Antibody screen
- blood type
- Rhesus type and antibody screening tests to detect antibodies potentially causing hemolytic disease of the newborn
Hct or Hgb and MCV
- Anemia- IDA and pernicious anemia
- Thallasemia (more common)
cervical cytology
-pap if due, not routine with pregnancy
presence of rubella infection
-therapeutic abortion should be considered (esp.
syphilis
test to prevent perinatal transmission of treponema pallidum
treat appropriately with positive test result
hepatitis B surface antigen screening
to prevent perinatal transmission, screen all women, even if previously tested or vaccinated
chlamydia and gonorrhea screening
- screen all pregnant women at 1st PN visit per CDC and ACOG
- USPSTF instead recommends limited screening for women 24 yr of age, and older women at incr risk
- causes conjunctivitis or pneumonia in infant
best test for chlamydia and gonorrhea
NAAT (nucleic acid amplification tests)
-endocervix or vaginal swab preferred for PN care, urine testing, or liquid based cytology specimens
thyroid function testing
- test at risk for thyroid dz (symptomatic women, personal or family hx, type 1 diabetes, etc)
- other experts say universal screening
untreated thyroid dz may result in
fetal neurological abnormalities
elevated thyroid peroxidase antibodies
testing is controversial - not routinely checked
HIV screening
- done routinely early in pregnancy using “opt out” approach
- with retroviral treatment, transmission is reduced to 2% along with avoiding breastfeeding and labor
- resting 3rd trimester (
Urine culture
- two consecutive voided urine specimens or a single catheterized urine specimen (not routinely done)
- pregnant women with untreated bacteriuria are at high risk for acquiring pyelonephritis, premature labor, low birth weight infants
Down syndrome screening
- all women should be offered aneuploidy screening before 20 weeks of gestation
- women of any age at high risk of Down syndrome with the appropriate diagnostic procedure for fetal karyotype instead of screening tests
First trimester combined test for Down Syndrome
- US for nuchal translucency (NT) and gestational age by crown rump length
- Serum pregnancy associated plasma protein (PAPP-A) and free or total hCG (9-13 weeks free hCG, 11-13 weeks total hCG)
for those who screen positive for Down syndrome follow with
chorionic villi sampling (CVS) (extract a piece of the placenta through a catheter). diagnostic. do in first trimester
Full integrated test
- Highest detection rate for Down’s syndrome, lowest screen positive
- US measurement NT at 10-13 weeks
- PAPP-A at 10-13 weeks
- Quadruple test at 15-18 weeks- (Alpha fetoprotein (AFP), unconjugated estriol (uE3), hCG, inhibin A)
Serum integrated test
- Same as full integrated test without the US measurement of NT
- Used in areas where the woman does not have access to technicians who can adequately measure NT
Quadruple test measures what?
serum AFP, uE3, hCG, and inhibin A
Quadruple test performed when?
15-18 weeks gestation
Genetic sonogram
18-20 weeks gestation
-not useful as primary screening test
New DNA testing
maternal plasma DNA
for those who screen positive follow with
CVS first trimester
Amniocentesis second timester
varicella testing
- test all pregnant women for immunity
- if exposed during pregnancy, administer varicella zoster immune globulin (VariZIG prophylaxis)
bacterial vaginosis
screening not recommended in routine prenatal care - if asx don’t need to treat
only treat sx
herpes simplex virus
Routine testing generally not recommended in asymptomatic women
Type specific screening may be reasonable in asymptomatic partners in symptomatic men
Chagas disease
Parasitic disease endemic to Latin America
Consider testing in women who lived in the area
Women may be asymptomatic and infection can be transmitted to the fetus
Lead testing
Not usu tested, unless mother is thought to have exposure
Diagnosis
Lead levels 5mcg/dL- follow up is dependent upon levels
-Pediatrician should be told of mother’s lead levels at delivery
-Lead will cross the placenta, associated with miscarriage and still birth
-Breastfeeding-levels in breastmilk should be evaluated
Ultrasound
US useful early in pregnancy to establish EDD
Randomized studies have shown good EDD reduce unnecessary inductions
First trimester US can detect fetal malformations and multiple pregnancies earlier
Neural Tube Defect Screening and Down Syndrome Screening
All women should be offered screening if not done in the first trimester
Gestational Diabetes
All pregnant women should be screened at 24-28 weeks gestation
Consider first trimester screening with significant risk factors:
Obesity
Previous GD
Previous macrosomia
Sexually transmitted Disease
CDC recommends repeating testing 28-36 weeks in: women with previous prenatal diagnosis of STD or those with continued risk factors
CDC recommends retesting Chlamydia in all women
CBC and antibody screening
Repeat in third trimester for anemia screening
Repeat antibody screening in unsensitized RH neg women although data shows that repeat testing may not be necessary if the initial screen was negative. Administer Rhogam as indicated
Group B beta-hemolytic streptococcus screening
All pregnant women should be screened 35-37 weeks gestation with samples both lower vagina and rectum
Components of second and third trimester ultrasound
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 (biparietal diameter and/or head circumference, femoral length, abdominal diameter and/or circumference)
Evaluation of the uterus, cervix, adnexa when clinically appropriate
Fetal anatomic survey
US in third trimester recommendations
to assess intrauterine growth restriction (IUGR)
Routine screening in third trimester is not recommended to screen for IUGR in low risk women.
Biophysical Profile-to assess fetal well being
Fetal movement Fetal tone Fetal breathing Amniotic fluid volume Results of nonstress testing(not always performed)
