Multiple Gestations

Question 1

A mother with a multiple gestation is at risk for what complications

Answer 1

preeclampsia, 3rd trimester bleeding, and prolapsed cord

Question 2

What is preeclampsia

Answer 2

complications of pregnancy
characterized by increasing hypertension, proteinuria, and edema

Question 3

What is advanced maternal age a risk factor for?

Answer 3

aneuploidy- down syndrome

Question 4

When is nuchal translucency performed?

Answer 4

1st trimester

Question 5

What kind of aneuploidy testing is done in the second trimester

Answer 5

maternal age, serum screening, and ultrasound or a combination

Question 6

What is a pregnancy at risk of with a shortened cervical length <25mm at 20 weeks

Answer 6

significant risk of of preterm delivery. (3-5x more likely when cx is shortened with twins)

Question 7

How do you measure growth discrepancy in twins?

Answer 7

(Estimated fetal weight of larger fetus - EFW of smaller fetus) / EFW of larger fetus

Question 8

What are the possible combinations of twin positioning at delivery?

Answer 8

A and B cephalic, A breech B cephalic, A cephalic B breech, A and B breech

Question 9

Which baby is baby A? Is baby A born first or second

Answer 9

closest to cervix and will be delivered first

Question 10

How is vaginal vs C-section birth determined with twins?

Answer 10

It depends on baby A. If baby A is breech they will do a c-section, regardless of B’s position. If B is breech but A is not they will deliver A vaginally and B will likely flip once it has room. If both are cephalic they will deliver vaginally.

Question 11

What are dizygotic twins?

Answer 11

Two eggs fertilized by two sperm. Always fraternal dichorionic-diamniotic twins

Question 12

What are monozygotic twins

Answer 12

One egg fertilized by one sperm that divides in the first 14 days after fertiliziation. they can be mono-mono, mono-di, or di-di

Question 13

Why do monochorionic twins have a higher risk of loss

Answer 13

prematurity, TTTS, and abnormalities

Question 14

When is best time to determine chorionicity/amnionicity? What is a diagnostic pitfall at this time?

Answer 14

The first trimester. A pitfall at this time is an “appearing twin”

Question 15

What must be documented in the second and third trimesters to determine placentation

Answer 15

gender and characterization of the membrane dividing the placenta. If genders are different or 2 placentas are seen, then it is dichorionic.

Question 16

How many membrane layers indicate monochorionic pregnancy

Answer 16

2. more than 2 suggests dichorionic.

Question 17

What is the most accurate predictor of dichorionic placenta?

Answer 17

the twin peak sign or separate placentas

Question 18

What is T-sign

Answer 18

A clear whisp of amnion coming straight off the placenta indicating a monochorionic-diamniotic pregnancy.

Question 19

When must cell division of the zygote occur in order for conjoined twins to be created

Answer 19

after 13 days from conception

Question 20

What is twin to twin transfusion

Answer 20

A donor twin bleeds into the circulation of a recipient twin. The donor is hypovolemic and has oligohydramnios.

Question 21

What occurs when there is an arteriovenous shunt in the placenta? How does this work

Answer 21

TTTS- arterial blood of one twin is pumped into the other twin’s veins. one will be anemic and growth restricted

Question 22

Why does TTTS cause poly and oligohydramnios

Answer 22

The twin with less blood flowing through the kidneys will have less urination and less fluid. The opposite happens for the other twin.

Question 23

Why are mono-mono twins at higher risk for TTTS

Answer 23

they share a placenta so their circulation is already connected

Question 24

What are the 3 types of anastomoses with TTTS

Answer 24

V-V, A-A, A-V

Question 25

What is stuck twin syndrome

Answer 25

the donor twin has less fluid so it may become fixed or stuck to the membrane

Question 26

What are sonographic features of TTTS

Answer 26

abnormal cord doppler, hydrops, heart failure, weight difference over 20%, non-vis donor bladder, size difference

Question 27

How is TTTS managed?

Answer 27

amniocentesis to drain polyhydraminos of recipient, ablation of communicating vessels

Question 28

What is Twin Embolization Syndrome

Answer 28

A severe complication where one twin dies in the womb leading to thrombus or toxins traveling into the blood supply of the surviving twin

Question 29

What is velamentous insertion? Is it common?

Answer 29

umbilical cord inserts into chorion instead of placenta. It occurs 1% of singletons but is more frequent with multiples

Question 30

What is the impact of Twin Embolization Syndrome

Answer 30

damage to all vascular organs but especially brain and kidneys

Question 31

What is Twin Reversed Arterial Perfusion

Answer 31

a complication of monochorionic twin pregnancy where the twins blood supplies are connected

Question 32

What kind of twins will result from a dizygotic pregnancy? Why?

Answer 32

di-di twins. Two fertilized eggs each develop with their own amnion and chorion.

Question 33

What kind of twins result from a monozygotic pregnancy? Why?

Answer 33

It depends on what phase the egg splits. splitting early on (0-3 days) creates di-di twins. Splitting between days 4-8 will create mono-di twins. splitting between days 9-12 will create mono-mono twins. After 13 days it will create conjoined twins.

Question 34

What is an amnion

Answer 34

The innermost sac that cushions the fetus and holds amniotic fluid

Question 35

What is a chorion

Answer 35

The outer sac that contains the amnion and develops the placenta

Question 36

How do you measure amniotic fluid in twin pregnancies? What is the normal range?

Answer 36

A Maximum Vertical Pocket (MVP) measurement is obtained for each sac. Normal range is 2-8 cm.

Question 37

What is the difference between TTTS and TRAP

Answer 37

TTTS is a blood imbalance from vascular connections in placenta causing unequal bloodflow between donor and recipient twin. TRAP is a severe, variant where a pump twin with working heart supplies an acardiac/acephalic twin with blood.

Question 38

What is Xiaphopagous

Answer 38

twins conjoined at the xiphiod cartilage

Question 39

What is Craniopagus

Answer 39

twins conjoined at the cranium but bodies are separate

Question 40

What is Pygopagus

Answer 40

twins conjoined at the ischial or hip region

Question 41

What is Ischiopagus

Answer 41

twins conjoined at the buttock

Question 42

What is Cephalopagus? Why is it fatal?

Answer 42

twins conjoined at the heads, will not survive due to malformation of brain

Question 43

What is Cephalothoracopagus? Is it fatal?

Answer 43

twins conjoined at the head and thorax, will not survive

Question 44

What is Dicephalus? How many arms and legs do they have?

Answer 44

twins conjoined at the body, but with two separate heads, 2 legs and 2-4 arms

Question 45

What does T-sign indicate?

Answer 45

monochorionic-diamniotic pregnancy

Question 46

What does lambda sign indicate?

Answer 46

lambda sign indicates dichorionic-diamniotic.