Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Obstetrics > Multiple Pregnancies > Flashcards

Multiple Pregnancies Flashcards

1
Q

What is the epidemiology of multiple pregnancies?

A

While rates of identical twins are constant throughout the world (3:1000), the rates of non-identical twins differ (higher in Africa, lower in developed countries).

In developed countries, actual incidence is higher than the natural due to IVF and assisted conception techniques.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What proportion of multiple pregnancies are due to assisted reproduction techniques?

A

25% of twins, 50-60% of triplets and 75% of quadruplets.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the risk factors for multiple pregnancy?

A
  • IVF
  • Previous history of twins
  • Increasing maternal age
  • Increasing parity
  • Family history of dizygotic twins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is zygosity?

A

Refers to whether twins have come from the same ovum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is chorionicity?

A

Refers to whether twins have the same placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the epidemiology of dizygotic twins?

A

These account for 70% of all twins

These twins are dichorionic diamniotic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the epidemiology surrounding monozygotic twins?

A

These account for 30% of all twins

These twins can be DCDA, MCDA, MCMA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What determines the sharing of placenta or amniotic sac?

A

The day at which division of the ovum occurs:

Before day 4: DCDA

Between day 4 and 8: MCDA

After day 8: MCMA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is chorionicity determined?

A

By ultrasound - different signs point to the diagnosis of one or two placenta, and one or two amniotic sacs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the rates of foetal loss, as determined by chorionicity?

A

Rates of death are higher for monochorionic twins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the rates of pre-term delivery, as determined by chorionicity?

A

Rates of pre-term labour are higher for monochorionic twins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the main pregnancy complications of multiple pregnancy?

A

Perinatal:

  • Polyhydramnios
  • Pre-eclampsia
  • Anaemia
  • Miscarriage
  • Antepartum haemorrhage

Maternal:

  • Increased perinatal mortality
  • Prematurity
  • Growth restriction and foetal distress
  • Twin-Twin Transfusion syndrome
  • Congenital abnormalities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the difference in rates of structural abnormalities in multiple pregnancies compared to singletons?

A

Structural defect rates are similar, but monochorionic twins have 2-3 times the risk than dichorionic twins.

Abnormalities are usually confined to one twin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Explain the maternal complications of multiple pregnancy

A

Hyperemesis: increase hCG
Anaemia: increased plasma volume
APH: placenta praevia is more common, as is placental abruption
Pre-eclampsia: earlier, and more severe than singleton

Other complications: GDM, oedema, PPH, varicose veins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the added risk of congenital abnormalities in multiple pregnancies?

A

Maternal risk of Down’s syndrome is doubled

Maternal serum screening is poor so nuchal translucency is more accurate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the risk of premature birth?

A

Multiple pregnancies usually deliver before 40 weeks:

Twins: at 37-38 weeks
Triplets: by 32-34 weeks

MC twins have higher rates of pre-term than DC

17
Q

What causes pre-term labour in multiple pregnancies?

A
  • Uterine expansion
  • Early myometrial contractility
  • TTTS
18
Q

What is the association of intrauterine growth restriction and multiple pregnancies?

A

Twins grow normally until weeks 28-30
Approximately 30% of all twins have growth restriction, with monochorionic twins being at higher risk and differences between twins affect 12% of pregnancies.

19
Q

If one of the twins die, what are the risks to the other twin?

A

If before the first trimester, this has no adverse effect. In the second or third trimester, it precipitates labour - 90% of all second/third trimester IUDs result in labour within 3 weeks.
In monochorionic twins, adverse effects to the other twin have a higher risk.

20
Q

What is twin-twin transfusion syndrome?

A

Here, there is a net flow of blood from one twin to the other, due to anastomoses between arties and veins in monochorionic twins (this does not occur in dichorionic twins).

Recipient: hyperdynamic, high-output cardiac failure and polyhydramnios
Donor: oliguria, oligohydramnios, growth restriction

21
Q

How is twin-twin transfusion syndrome treated?

A

Either with serial amniodrainage or laser ablation of anastomoses (laser ablation has better prognosis).

22
Q

How is twin-twin transfusion syndrome diagnosed?

A

By ultrasound

23
Q

What are the typical presentations at birth of multiple pregnancies?

A
  • Cephalic/cephalic (40%)
  • Cephalic/breech (40%)
  • Breech/cephalic (10%)
  • Other (10%)
24
Q

What is the management of multiple pregnancies?

A

Throughout pregnancy:

  • Folic acid throughout
  • Thromboprophylaxis from 12 weeks

Initial visit:

  • Determine chorionicity
  • Counsel on high risk, iron and folate

Subsequent visits:

Monochorionic:

  • Every two weeks after wk16 to evaluate TTTS
  • Detailed structural survey at wk18
  • Detailed foetal cardiac survey at wk20-22

Dichorionic

  • Every 2-4 weeks after wk24
  • Detailed structural survey at wk18
25
Q

What is the management of multiple pregnancy delivery?

A

For twins:

Common practice:

  • If appropriate for vaginal delivery: IOL at 38-40 weeks
  • If inappropriate for vaginal delivery: CS at 38 weeks

Vaginal delivery:
- ONLY if first presentation is cephalic

Indications for C-section:

  • Breech first presentation
  • Triplets
26
Q

How is vaginal delivery managed in twin pregnancies?

A

First stage:

  • Similar to singleton
  • Both twins monitored with CTG, but better to monitor first with scalp electrode to avoid double-monitoring

Second stage:
- First twin is delivered normally

Second twin:

  • Stabilise lie of the second twin with abdominal palpation
  • VE to assess presentation of second twin
  • If second lie is not longitudinal: ECV
  • If ECV fails, internal podalic version
  • Syntocinon infusion ready if uterine contractions reduce
  • Membranes of twin II should not broken until it is engaged

Obstetrics (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions