WH Labs and Imaging

Question 1

Estrogen types

Answer 1

*Estrone (E1),Estradiol (E2), Estriol (E3)
* Majority is produced by the placenta

Question 2

causes of Low levels of estrogen

Answer 2

• Possible problem w/ placenta
• Can indicate some birth defects such as Down Syndrome
• Difficulty w/ spontaneous labor if still low at term

Question 3

Causes of high levels of estrogen

Answer 3

• Increased risk of premature labor if sudden spike before week 37

Question 4

Progesterone functions

Answer 4

• Thickens uterine lining and prevents ovulation during pregnancy
• Produced by the corpus luteum and then by the placenta
• Should increase throughout pregnancy

Question 5

Causes of low levels of progesterone

Answer 5

• Infertility, higher risk of preterm labor/miscarriage and
  pre-eclampsia
• Can signal ectopic pregnancy

Question 6

Causes of high levels of progesterone

Answer 6

Multiples, molar pregnancy

Question 7

Follicle Stimulating Hormone (FSH)

Answer 7

• Produced by the pituitary gland
• Stimulates estrogen production and maturation of follicles in the ovary
• Suppressed by high levels of estrogen/progesterone
• High levels (>25.8) = postmenopausal, infertility hypopituitarism

Question 8

Luteinizing hormone (LH)

Answer 8

• Produced by the pituitary gland
• LH surge causes ovulation (so can be used to track ovulation)
• Stimulates the corpus luteum to produce progesterone (supports early
  stages of pregnancy)
• Low levels = postmenopausal, infertility, hypopituitarism

Question 9

Prolactin

Answer 9

• Produced by pituitary gland
• Stimulates lactation
• Elevated in pregnant and breastfeeding women

Question 10

Causes of Low levels of prolactin

Answer 10

Infertility, lack of milk production, not pregnant or breastfeeding, hypopituitarism

Question 11

High levels of prolactin causes

Answer 11

pregnancy/breastfeeding, prolactinoma, antipsychotics

Question 12

ABO incompatibility

Answer 12

• Often seen in firstborn infants (20%)
• Most group O women have developed anti-A and anti-B isoagglutinins
  before pregnancy from exposure to bacteria
• Rarely becomes progressive in future pregnancies
• Anti-A and anti-B antibodies are IgM
• Typically does not cause appreciable hemolysis in the fetus
• improved results since the 1950s

Question 13

Rh antibody screen

Answer 13

• Indirect Coombs test to test for maternal alloimmunization
• IgG antibodies = Rh incompatibility = fetal hemolytic anemia
• Rh incompatibility is progressive, affects second and
  subsequent pregnancies

Question 14

What is the grandmother effect?

Answer 14

• It is possible for an Rh- female fetus exposed to maternal Rh+ red cells to develop
  sensitization (while still in the womb)
• Means she may produce anti-D(Rh) antibodies before she is even born, so 1st pregnancy
  is already at risk
• The fetus in the current pregnancy is jeopardized by maternal antibodies that were
  initially provoked by his or her grandmother’s erythrocytes

Question 15

Rubella screening

Answer 15

• Titer
• Negative results are < 7 IU/mL IgG and < 0.9 IgM antibodies
• Infection in the first trimester poses significant risk for abortion and severe congenital
  malformations
• Rubella vaccination should be avoided 1 month before or during pregnancy

Question 16

Syphilis screening (RPR)

Answer 16

• Spirochetes cross the placenta to cause congenital infection, stillbirth
• Delivery
• Risk directly related to maternal spirochete load
• Treat ASAP after Dx

Question 17

HIV Screening

Answer 17

• Checked also at a patient’s initial visit
• Can lead to AIDS
• Can pass to fetus
• If positive, medications used to protect the fetus during delivery, and to baby after birth
• Passed through breastmilk

Question 18

Beta-HCG qualitative vs. quantitative testing

Answer 18

*Qualitative (You do this one at home)
*Detects the presence of HCG
*Urine

*Quantitative (β-hCG)
*Measures the amount present in
the blood
*Confirms pregnancy
*Doubles every 3 days and reach its
peak at 8-11 weeks of a normal
pregnancy
*US more accurate after 5-6 weeks
of gestation as this is more
accurate

Question 19

Quad screen: Screening test components

Answer 19

*Alpha-fetoprotein (AFP), made by baby
*Β-hCG, made by placenta
*Estriol, made by placenta and fetus
*Inhibin-A, made by placenta

Question 20

When is quad screening done and when should it be considered?

Answer 20

*Weeks 16-18
* Most accurate timing (can be done 15-22 wks)
*Consider if family history of birth defects, ≥ 35 years, diabetes with insulin, radiation exposure, viral infection during pregnancy, harmful medication or drugs use

Question 21

Alpha-fetoprotein (AFP)

Answer 21

*Most common reason for elevated levels is
inaccurate dating of pregnancy
*High levels may indicate a neural tube
defect
*Low levels AFP with abnormal hCG, inhibin
A, and estriol may indicate Trisomy 21 or 18

Question 22

Noninvasive prenatal testing (NIPT)

Answer 22

*Prenatal cell-free DNA (cfDNA)
*Screening blood test
*≥10 weeks
*Trisomy 21, trisomy 18, trisomy 13, fetal “Y” chromosome

Question 23

Noninvasive prenatal testing (NIPT) process

Answer 23

*DNA from the mother and fetus is extracted from a maternal blood sample and screened for the increased chance for specific chromosome problems
*97 to 99% accuracy for negative predictive values
*Chorionic villus sampling (CVS) or amniocentesis to confirm

Question 24

Oral Glucose Tolerance Test

Answer 24

OGTT
*50 grams
*1-hour glucose challenge (step 1)
*>140mg/dL is abnormal
*Diagnostic 3-hour oral glucose tolerance test (move to 3 hour if abnormal in 1 hour)

*Fasting: > 95 mg/dL
*1 hour: > 180 mg/dL
*2 hour: > 155 mg/dL
*3 hour: > 140 mg/dL
*If more than 1 is higher than
normal = gestational diabetes

Question 25

Amniocentesis

Answer 25

Removal of amniotic fluid by a needle through the maternal abdomen with ultrasound guidance

Question 26

Used to diagnose fetal chromosomal abnormalities or neural tube defects after an abnormal screening test

Answer 26

Amniocentesis

Question 27

Cordocentesis

Answer 27

*Percutaneous umbilical cord blood sampling *Usually done after week 17/18 *Can detect anemia, chromosome abnormalities, infections, blood disorders *Can’t detect neural tube defects

Question 28

Blood transfusions or medication can be given directly to the fetus through ______

Answer 28

the umbilical cord

Question 29

Chorionic Villus Sampling (CVS)

Answer 29

* Chorionic villi have the same genetic material as the baby * Transabdominal or transcervical * Can be used to detect chromosome abnormality or other genetic disorders * Can’t detect neural tube defects * Miscarriage risk of 0.7% * Limb defects (esp if done before 9 wks)

Question 30

L/S Ratio

Answer 30

Lecithin–sphingomyelin ratio in amniotic fluid * Surfactants * Higher lecithin/sphingomyelin ratio = more mature lungs * Test done 32-39 weeks if at risk of premature delivery

Question 31

Ranges for L/S ratio

Answer 31

<1.5:1 = immature lungs 1.5:1 – 1.9:1 = risk for immature lungs ≥2.1:1 = mature lungs

Question 32

Kleihauer-Betke (KB) Test

Answer 32

* Fetomaternal hemorrhage screening * Quantifies the amount of fetal hemoglobin in maternal circulation * Maternal trauma/placental disruption * Additional RhoGAM given if mother RhD negative

Question 33

Kleihauer-Betke (KB) Test process

Answer 33

* A peripheral blood smear is made from the maternal sample and treated with acid. The slides are washed, stained, and examined microscopically * The number of fetal cells are counted per number of maternal cells to give % fetal cells * Cannot be detected if less than 5mL blood shared

Question 34

Nitrazine Test process

Answer 34

*Premature rupture of membranes (PROM) *Prior to 37 weeks *Place a drop of fluid obtained from the vagina onto paper strips containing Nitrazine dye *The strips turn blue if the pH is greater than 6.0 *A blue strip means it's more likely the membranes have ruptured

Question 35

When allowed to dry, amniotic fluid results in a ______

Answer 35

fern pattern (ferning)

Question 36

Obstetric Ultrasound

Answer 36

*Transvaginal or abdominal *Initial US to confirm intrauterine pregnancy *Embryo can be observed at about 6 weeks *Heartbeat visible 6-7 weeks *If observed, probability of continued pregnancy high

Question 37

18-20 week scan

Answer 37

*Determine gestational age * Crown-to-rump length * Biparietal diameter * Femur length *Abdominal circumference *Amount of amniotic fluid *Placenta location *Number of fetuses *Malformations

Question 38

Other indications for US

Answer 38

*Preterm labor *PROM *Vaginal bleeding *Determine fetal presentation *Decreased fetal movement *Most offices do 1-2 during 1st trimester, one at 20 weeks, and then PRN to assess.

Question 39

Doppler US use in pregnancy

Answer 39

*10 weeks (can hear heartbeat) *110-160 beats per minute on average

Question 40

What does an External fetal heart rate monitor do?

Answer 40

Heart rate and contractions

Question 41

Internal fetal monitor indications for use

Answer 41

* Electrode wire on baby’s scalp * Only used if amniotic sac is ruptured and cervix is open * DON’T use in HIV+ moms

Question 42

Hysterosalpingogram

Answer 42

* Fluoroscopy of the uterus and fallopian tubes * Contrast injected through the cervix * Most commonly used in the evaluation of infertility

Question 43

Group B Strep Testing importance

Answer 43

* GBS typically harmless in healthy adults, normal bacteria in lower GI tract * Can cause serious illness in newborns * pneumonia, meningitis, sepsis ● Test in the 3rd trimester at 36-37 weeks of pregnancy ● Vaginal and Rectal swab ● If (+) then Abx treatment during labor (penicillin)