OB Complications III-Castro

Question 1

What antibodies can cause hydrops fetalis in a Rh(D) positive fetus?

Answer 1

anti-D antibodies from the mother

-Rh negatives mom who are exposed to Rh + RBCs can produce anti-D antibodies which cross the placenta, opsonize fetal RBCs and cause hemolytic anemia, extra-medullary hematopoiesis, umbilical and portal venous obstruction and hydrops fetalis

(IgM produced in the first pregnancy cannot cross the placenta but IgG in later pregnancies CAN cross the placenta)

Question 2

What is Hydrops Fetalis? What are the two types?

Answer 2

-Hydrops fetalis is in-utero heart failure

can be immune (Rh Antibody) or non-immune (parvovirus infection)

Question 3

What are the US signs of hydrops fetalis?

Answer 3

enlarged placenta, fetal ascites, pericardial effusion, pleural effusion, subcutaneous edema (scalp edema) and polyhydramnios)

fluid in 2+ body spaces

Question 4

What are the 2 non-Rh RBC antigens that are important to know because they can cause in utero hemolysis or Hydrops Fetalis if the mother is - for these antigens?

Answer 4

Kell (Kell kills)

Duffy (Duffy dies)

Question 5

Antibodies to what RBC antigens do not affect the fetus?

Answer 5

Lewis A and B (produce IgM antibodies –>do NOT cross the placenta Lewis Lives!

Question 6

What is the next step if a pregnant women has a + antibody screen?

Answer 6

obtain an antibody identification AND titer to determine if it is anti-D (or other antibody that can cause hydrops) or another benign antibody (Lewis A)

Question 7

If the women is Rh(D) neg/ Antibody screen pos, what is the next step?

Answer 7

-paternal Rh(D) antigen testing with zygosity

–> if heterozygous, check fetal Rh(D) antigen status (in maternal blood)

• if the fetus is Rh(D) +, Recheck maternal titer every 4 weeks after 20 weeks gestation
• if rise to 1:16 or greater obtain serial MCA dopplers on fetus because the fetus is at risk for hydrops fetalis

Question 8

If the fetus is Rh+ and the mom is Rh- with Anti-D antibodies, what should be used to monitor the fetus for Hydrops?

Answer 8

Recheck maternal titer every 4 weeks after 20 weeks gestation

*if rise to 1:16 or greater obtain serial MCA dopplers on fetus because the fetus is at risk for hydrops fetalis

Question 9

What do elevated fetal MCA dopplers indicate? What is the next step in management?

Answer 9

fetal anemia

• Proceed with umbilical blood sampling (PUBS) and intra umbilical fetal transfusion
• Steroids to enhance fetal lung maturity
• consider delivery after 35 weeks
• Serial fetal sonos for growth, r/o hydrops and antenatal testing

Question 10

What test can be ordered if it is suspected that an Rh- mom has been exposed to Rh+ blood? What can the mom be given to block the immune response?

Answer 10

Kleihauer Betke can be used to determine extent of fetal maternal hemorrhage (estimates no. of fetal cells in maternal circulation)

*Rh Immune Globulin acts by blocking antigenic sites and suppression of B cell response

Question 11

When do you give Rh Immune Globulin?

Answer 11

-at 28 weeks to RH(D) neg, unsensitized (anti D neg) pregnant women
AND
again within 72 hours of delivery IF neonate is Rh(D) pos

-to any RH (D) neg, unsensitized (anti D neg) pregnant woman with an abortion, ectopic, vaginal bleeding, abdominal trauma or if any potentially traumatic procedure done (such as amniocentesis, external version)

Question 12

What is placenta previa? What are the different types?

Answer 12

The placenta is located over the cervical internal os or near it (normally decreases with advancing gestation due to enlargement of the uterus and placental migration)

• complete: internal os completely covered
• partial: internal os partially covered
• marginal: placental edge at martin of the internal os
• low lying placenta: placenta near the os in the lower segment (not as concerning)

Question 13

What are the important risk factors in placenta previa?

Answer 13

hx of placenta previa and scarred uterus (prior c-section)

also, inc maternal age, uterine anomalies, tobacco use, multiple gestation

Question 14

What are the signs and symptoms of placenta previa?

Answer 14

-Sudden onset of painless vaginal bleeding (Bleeding episodes are self limiting)

OR

-Asymptomatic patient, diagnosis made incidentally on ultrasound

Question 15

How is a placenta previa diagnosed? What should NOT be done if it is suspected in the 3rd trimester?

Answer 15

Ultrasound*

***do NOT do a vaginal exam on 3rd trimester unless r/o on US first

Question 16

How should placenta previa be delivered?

Answer 16

C-section ONLY***

Question 17

What is Abrupto Placenta? What are the maternal risk factors?

Answer 17

Premature separation of the normally located placenta

types: Internal bleeding (concealed) and external bleeding
* risk factors=ANY vascular disease (HTN, smoking, trauma, drugs, PROM, short umbilical cord, folate deficiency, inc. maternal age)

Question 18

What are the signs/symptoms of Abruption? Can it be ruled out by US?

Answer 18

-Painful vaginal bleeding & uterine contractions
-Tender uterus with increased tone
-Signs of fetal hypoxia or IUFD
hypovolemic shock rom hemorrhage & -DIC

**Ultrasound-NOT RELIABLE TO R/O ABRUPTION. It is a clinical diagnosis

Question 19

What is Vasa Previa?

Answer 19

• fetal bleeding
• Velamentous cord insertion or succenturiate lobe of placenta can result in vasa previa
• Fetal vessels traverse the cervical os and tear open with rupture of membranes
• most lethal condition for fetuses**

Question 20

What is the classic presentation of Vasa Previa?

Answer 20

• with some vaginal bleeding that occurs after rupture of membranes
• associated with abnormal fetal heart rate patterns (decelerations, sinusoidal heart rate pattern, fetal tachycardia followed by bradycardia)
• Minimal bleeding may cause severe fetal compromise b/c fetal blood volume is small

Question 21

How should a Vasa Previa be delivered?

Answer 21

by emergency c-section

want to diagnose by US PRIOR TO labor so it doesn’t rupture

Question 22

When is uterine rupture suspected? How is this diagnosed? What is the treatment?

Answer 22

• H/O previous uterine surgery-myomectomy, cesarean section-more likely if previous classical cesarean or multiple low transverse cesareans.
• Occurs mostly during labor
• clinical diagnosis–> know when to expect it*
  tx: emergency c-section