Lecture 19: Multfetal Gestation and Malpresentation Flashcards

1
Q

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?

A
  • 0-3 days = dichorionic, diamniotic
  • 4-8 days = monochorionic, diamniotic
  • 9-12 days = monochorionic, monoamniotic
  • >13 days = conjoined twins
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2
Q

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

A

Monochorionic, diamniotic due to cleaveage at days 4-8

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3
Q

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

A

Monochorionic monoamniotic

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4
Q

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

A

Dizygotic

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5
Q

Having dizygotic twins is 2x more common when?

A

After 35 y/o

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6
Q

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

A

Determination of zygosity!

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7
Q

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

A
  • Different fetal gender
  • Visualization of thick amnion-chorion septum
  • “Peak” or “inverted V” sign at base of septum
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8
Q

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

A

Fairly thin

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9
Q

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

A
  • 90% occur in monochorionic twins
  • Most common type is arterial-arterial
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10
Q

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

A

Heart failure

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11
Q

What are treatment options for twin-twin transfusion syndrome?

A
  • Serial amniocentesis w/ amniotic fluid reduction has been historically done
  • Laser photocoagulation of the anastomosis vessles on the placenta is performed nowadays
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12
Q

What occurs in Acardiac Twin?

A
  • 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
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13
Q

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

A

Velamentous umbilical cord insertions

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14
Q

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

A
  • Can devlop DIC
  • Check platelets and fibrinogn levels weekly
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15
Q

What is fetus papyraceus?

A

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

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16
Q

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

A

q 4-6 weeks begin at 24 weeks

17
Q

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

A
  • Hospitalize at 26 weeks and deliver at 32 weeks
  • Secondary to ↑ risk of lethal cord entaglement
18
Q

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

A

38 weeks

19
Q

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

A
  • 2nd twin = ↑ risk of cord prolapse, placental abruption, and malpresentation
  • Be prepared for postpartum hemorrhage 2’ to uterine atony
20
Q

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

A

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

21
Q

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

A

Prematurity; before 28 wks around 25% will be breach

22
Q

What is the most common breech presentation?

A
  • Frank
  • Thighs are flexed
  • LE’s are extended at knee
23
Q

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

A

36 weeks gestation NOT in labor

24
Q

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

A

7 hours

25
Q

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

A
  • Must be in frank or complete breech presentation
  • Gestational age >37 weeks
  • Fetal head MUST be flexed
26
Q

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

A

All by C-section

27
Q

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

A

Allow fetus to deliver to the scapulae

28
Q

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

A

PIPER forceps

29
Q

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

A
  • Mentum anterior CAN deliver vaginally (MAV)
  • Mentum posterior CANNOT; must do C-section
30
Q

What is a compound presentation?

A

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