Multiple gestation with FGR

Question 1

How is FGR diagnosed in a multiple gestation?

Answer 1

Same as singleton. EFW less than 10%ile and or discordance more than 25%

Question 2

What is your differential diagnosis when FGR is diagnosed in a single fetus of a dichorionic twin gestation?

Answer 2

Suggests placental insufficiency, anastomoses, bilateral renal agenesis or genetic abnormality

Question 3

How do you counsel the patient about the risks of FGR in a single twin?

Answer 3

Stilbirth, IUFD, placental disorders, GR of the other twin, PTD

Question 4

What is the significance of discordant twin growth?

Answer 4

Defined as a 20% difference EFWs

Discordance with AGA growths are not at increased risk of fetal or neonatal morbidity and mortality

Discordance with sFGR growth associated with a 7.7-fold increased risk of major neonatal morbidity

Question 5

What is the staging for selective growth restriction in monochorionic pregnancy?

Answer 5

Stage 1 - growth restriction with normal flow or decreases flow. Deliver between 34-35 weeks

Stage 2 - growth restriction with persistent absent or reverse end diastolic velocity. Deliver between 26-32 weeks (deliver at 28 weeks)

Stage 3 - growth restriction with intermittent absent or reverse or forward flow (at highest risk of spontaneous still birth, seen in 10% and of demise then 10% risk of neurologic disease in surviving twin). Deliver at 32 weeks gestation

Question 6

How often is selective growth restriction seen in monochorionic pregnancy?

Answer 6

10% of monochorionic pregnancies

Question 7

Treatment for stage 2 selective growth restriction in monochorionic pregnancy include:

Answer 7

• termination of pregnancy depending on gestational age
• expectant management
• cord occlusion in stage 2 selective growth restriction

No laser because one placenta is smaller than another so removal of the anastomoses won’t help.

Question 8

Etiology of selective growth restriction in monochorionic twins

Answer 8

Unequal share of placenta between the twins.

Ultrasound clue: eccentric (marginal) or velamentous cord in twin that is growth restricted verses central cord in twin that is not growth restricted

Pathology clue: placenta will show arterial to arterial anastomoses, a way for the restricted baby to get blood from the normal weight baby