Fetal Therapy

Question 1

What was the first condition that fetal therapy was used for?

Answer 1

Hydrops - would transfuse following Rh immunization

Question 2

What are corticosteroids used for in fetal therapy?

Answer 2

to help preterm babies survive/thrive by bulking up the lungs

Question 3

What are the indications/goals of fetal therapy?

Answer 3

• correct or stabilize an anomaly
• allow continued in utero development
• prevent neonatal complications due to fetal anomaly

Question 4

What are the criteria for fetal surgery?

Answer 4

• accurate diagnosis and staging is possible
• natural history of the disease is known
• no effective postnatal therapy
• in utero surgery has been proven feasible in animal models
• interventions performed in specialized fetal treatment centers, protocols, informed consent

Question 5

What does the two-hit hypothesis refer to?

Answer 5

a birth defect or anomaly will develop by a certain point but still be susceptible to further development throughout pregnancy (e.g. spina bifida)

Question 6

How may fetal interventions be performed?

Answer 6

Maternal treatment, surgery on the fetus, surgery on the cord/placenta

Question 7

What are some of the contraindications for a CVS?

Answer 7

red cell alloiummunization, HIV, Hep B, Hep C, presence of an IUD

Question 8

How might a high/arrhythmic heart rate be treated in a fetus?

Answer 8

• anti-arrhythmic medications delivered into umbilical or peritoneal areas
• if hydrops/excess fluid is present, it should be aspirated off

Question 9

How does red blood cell alloimmunization come about?

Answer 9

If the pregnant person in Rh negative and baby is Rh positive, some of those Rh positive cells will get into her blood stream and she will make antibodies

Question 10

What can red blood cell alloimmunization lead to?

Answer 10

Antibodies for Rh positive cells can cross into Rh positive baby and cause severe anemia, heart failure, and hydrops

Question 11

What are some predictors of severity with red blood cell alloimmunization?

Answer 11

Multiple antibodies and presence of the Kell antigen which can lead to hemolysis and erythropoietic suppression

Question 12

What strategies are available for testing of Rh(D) antigen?

Answer 12

Could do D typing on dad and then do zygosity testing to determine linkage; fetal genotype can be determined through amniocentesis (CVS contraindicated!); UNITY offers Rh(D) testing

Question 13

How can anemia be assessed in a fetus?

Answer 13

Use of an MCA doppler which measures the speed of blood through the cerebral artery (gets faster with progressive anemia)

Question 14

How is anemia treated in the fetus?

Answer 14

With transfusions likely into the intraperitoneal (IPT) space

Question 15

What is the importance of Fc blocking antibody?

Answer 15

Prevents crossing of Rh positive antibodies into the placenta; prevents anemia in the first place so may mitigate the need for transfusions altogether

Question 16

In which type of pregnancy can twin twin transfusion syndrome develop?

Answer 16

Mono(zygotic), mono(chorionic)

identical twins with one placenta

Question 17

What happens to the donor baby in twin twin transfusion syndrome?

Answer 17

High vascular resistance, hypovolemia, release of mediators Endothelin 1 and Angiotensin II
oligohydramnios

Question 18

What happens to the recipient twin in twin twin transfusion syndrome?

Answer 18

increased preload, transferred vasoactivate mediators, polyhydramnios, myocardial remodelilng
their heart can become overwhelmed
can lead to hydrops and fetal death

Question 19

What does Cincinnati staging refer to?

Answer 19

Five stages of cardiomyopathy, offering a prognosis based off symptoms

Question 20

What are the treatment options in twin twin transfusion syndrome?

Answer 20

• no treatment: 80-90% mortality
• serial amnioreduction: take some amniotic fluid from the recipient baby and give it to the donor; leads to 50% survival
• laser photocoagulation: odds that one twin survives: 75-92%; odds that both twins survive: 45-68%
• fetal cord occlusion: umbilical cord ligation/cautery; termination of one twin leads to 50% survival

Question 21

When does twin twin transfusion syndrome typically present?

Answer 21

Between 16 and 26/28 weeks

Question 22

What is ex-utero intrapartum treatment (EXIT)?

Answer 22

Anesthesia is delivered to mother/fetus
uterus is relaxed and blood flow is preserved so that oxygen is still getting to the baby through the placenta
the fetus is partially delivered in this state, allowing for a complete delivery later on

Question 23

What are common indications for using the EXIT procedure?

Answer 23

Stickler syndrome, Pierre Robin sequence, diaphragmatic hernia

Question 24

What is a CCAM?

Answer 24

Fetal chest mass/hamartomatous growth of tissue
Not connected to the airway part of the lungs, usually small but complications can include hydrops, compression of mediastinal structures, pulmonary hypoplasia

Question 25

How might a CCAM be treated if complications arise?

Answer 25

Solid masses - mom can be given steroids

Cystic masses - fluid should be removed or shunted out to prevent hydrops

Question 26

What percentage of cases of spina bifida are associated with aneuploidy or another genetic abnormality?

Answer 26

5-6%

Question 27

What are the main concerns with spina bifida?

Answer 27

muscle control below injury; CNS impairment due to Chiari malformation/hydrocephalus

Question 28

What are some innovations in fetal therapies on the horizon?

Answer 28

• Improvement of congenital heart disease, specifically HLHS or HRHS by use of a catheter
• for diaphragmatic hernia, placement of a fetal endoscopic tracheal occlusion to prevent hypoplastic lungs
• in utero stem cell/gene therapy for conditions like osteogenesis imperfecta and alpha thalassemia major and Hemoglobin Bart’s