Lecture 19: Multfetal Gestation and Malpresentation

Question 1

How does the nature of the membranes for monozygotic twins change if time of cleavage is between 0-3, 4-8, 9-12, or >13 days?

Answer 1

• 0-3 days = dichorionic, diamniotic
• 4-8 days = monochorionic, diamniotic
• 9-12 days = monochorionic, monoamniotic
• >13 days = conjoined twins

Question 2

What is the most common presentation of membranes for monozygotic twins?

Answer 2

Monochorionic, diamniotic due to cleaveage at days 4-8

Question 3

Which presentation of monozygotic twins is the most dangerous since there are not separating amnions?

Answer 3

Monochorionic monoamniotic

Question 4

2/3’s of spontaneous twins are (mono- or dizygotic)?

Answer 4

Dizygotic

Question 5

Having dizygotic twins is 2x more common when?

Answer 5

After 35 y/o

Question 6

What is the most important step after diagnosing a twin pregnanc?

Answer 6

Determination of zygosity!

Question 7

How can a dizygotic twins be determined on U/S?

Answer 7

• Different fetal gender
• Visualization of thick amnion-chorion septum
• “Peak” or “inverted V” sign at base of septum

Question 8

What is characteristic of the dividing membrane seen on U/S for monozygotic twins?

Answer 8

Fairly thin

Question 9

90% of interplacental vascular anastomoses occur in what type of twins and what is the most common type of anastomosed vessels?

Answer 9

• 90% occur in monochorionic twins
• Most common type is arterial-arterial

Question 10

In twin-twin transfusion syndrome both twins are at risk of demise from what?

Answer 10

Heart failure

Question 11

What are treatment options for twin-twin transfusion syndrome?

Answer 11

• Serial amniocentesis w/ amniotic fluid reduction has been historically done
• Laser photocoagulation of the anastomosis vessles on the placenta is performed nowadays

Question 12

What occurs in Acardiac Twin?

Answer 12

• Arterial to arterial anastomoses between twins
• Recipient twin, being perfused in reverse direction w/ poor oxygenated blood fails to develop normally
• Fully formed LE’s w/ NO anatomic structures cephalad of abdomen

Question 13

What is the most frequent umbilical cord abnormalities seen in monozygotic twins?

Answer 13

Velamentous umbilical cord insertions

Question 14

If retained dead fetus syndrome occurs >20 weeks gestation what complication can develop in the mother; how should she be managed?

Answer 14

• Can devlop DIC
• Check platelets and fibrinogn levels weekly

Question 15

What is fetus papyraceus?

Answer 15

When retained dead fetus syndrome occurs >12 weeks and the fetus shrinks, dehydrates, and flattens

Question 16

With multifetal gestations how often should serial U/S’s for intrauterine growth be performed and starting when?

Answer 16

q 4-6 weeks begin at 24 weeks

Question 17

When should mother with monoamniotic twins be hospitalized and they should be delivered at how many weeks; WHY?

Answer 17

• Hospitalize at 26 weeks and deliver at 32 weeks
• Secondary to ↑ risk of lethal cord entaglement

Question 18

If no complications during pregnancy, it is recommended to deliver twins at how many weeks?

Answer 18

38 weeks

Question 19

During vertex-vertex presentation the second twin is at increased risk for what complications; should be prepared for what complication in mother?

Answer 19

• 2nd twin = ↑ risk of cord prolapse, placental abruption, and malpresentation
• Be prepared for postpartum hemorrhage 2’ to uterine atony

Question 20

If first twin is vertex but other twin is transverse or breech how should they be delivered?

Answer 20

CAN be vaginally, but will often be by C-section

Question 21

What is the most common factor associated with a breech presentation?

Answer 21

Prematurity; before 28 wks around 25% will be breach

Question 22

What is the most common breech presentation?

Answer 22

• Frank
• Thighs are flexed
• LE’s are extended at knee

Question 23

Who is a candidate for external cephalic version (ECV) to get baby into vertex position?

Answer 23

36 weeks gestation NOT in labor

Question 24

Before performing external cephalic version (ECV) patient should be NPO for how long?

Answer 24

7 hours

Question 25

Which breech position must baby be in to consider vaginal delivery and must be at what gestational age?

Answer 25

- **Must** be in **frank** or **complete** breech presentation - **Gestational age \>37 weeks** - Fetal head **MUST** be **flexed**

Question 26

What is the standard of care in most practices in terms of how to deliver a breech presenation?

Answer 26

**All** by **C-section**

Question 27

If doing a vaginal breech delivery how far should the baby be out before applying any traction?

Answer 27

Allow fetus to **deliver** to the **scapulae**

Question 28

Which special type of forceps are used in assisted breech deliveries?

Answer 28

**PIPER forceps**

Question 29

With a face presentation the fetal chin is the point of designation which of these babies CAN and which CANNOT be delivered vaginally?

Answer 29

- **M**entum **a**nterior **CAN** deliver vaginally (**MAV**) - **M**entum **p**osterior **CANNOT**; must do **C-section**

Question 30

What is a compound presentation?

Answer 30

When **fetal extremity** (usually the **hand**) is found prolapsed alongside the **presenting fetal part** (**head**)