Revision - Obs 4

Question 1

Where are bile acids produced?

Answer 1

Produced in the liver due to breakdown of cholesterol

Question 2

What complication is obstetric cholestasis associated with?

Answer 2

Increased risk of stillbirth

Question 3

Is there a rash associated with obstetric cholestasis?

Answer 3

No - if a rash is present, an alternative diagnosis should be considered, such as polymorphic eruption of pregnancy or pemphigoid gestationis.

Question 4

What can be given in clotting (prothrombin) time is deranged in obstetric cholestasis?

Answer 4

Water soluble vitamin K

Question 5

How can a lack of bile salts in obstetric cholestasis lead to vitamin K deficiency?

Answer 5

1) Bile acids are essential for the absorption of fat soluble vitamins (i.e. vitamin K)

2) A lack of bile acids (as in obstretric cholestasis) can therefore lead to a vitamin K deficiency

3) This can lead to impaired clotting

Question 6

Is fat soluble or water soluble vitamin K given in obstetric cholestasis?

Answer 6

Water soluble (won’t be able to absorb fat soluble due to lack of bile salts in obstetric cholestasis)

Question 7

Monitoring of obstetric cholestasis?

Answer 7

Monitor of LFTs is required during pregnancy (weekly) and after delivery (after at least ten days).

Question 8

Potential management of obstetric cholestasis when LFTs and bile acids are severely deranged?

Answer 8

Planned induction of labour at 37 weeks

Question 9

When does acute fatty liver of pregnancy typically occur?

Answer 9

3rd trimester or period immediately following delivery.

Question 10

Complications of acute fatty liver of pregnancy?

Answer 10

There is a high risk of liver failure and mortality, for both the mother and fetus.

Question 11

What enzyme is deficient in acute fatty liver of pregnancy?

Answer 11

long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD)

Question 12

Pathophysiology of acute fatty liver of pregnancy?

Answer 12

1) Acute fatty liver of pregnancy results from impaired processing of fatty acids in the placenta.

2) This is the result of a genetic condition in the fetus that impairs fatty acid metabolism: most common cause is LCHAD deficiency in the fetus.

3) This is an autosomal recessive condition (i.e. the mother will also have one defective copy of the gene).

4) The LCHAD enzyme is important in fatty acid oxidation, breaking down fatty acids to be used as fuel.

5) The fetus and placenta are unable to break down fatty acids.

6) These fatty acids enter the maternal circulation, and accumulate in the liver.

7) The accumulation of fatty acids in the mother’s liver leads to inflammation and liver failure.

Question 13

Role of LCHAD enzyme?

Answer 13

Important in fatty acid oxidation (breaking down fatty acids to be used as fuel).

Question 14

What can severe acute fatty liver of pregnancy result in?

Answer 14

Pre-eclampsia

Question 15

Main investigation in acute fatty liver of pregnacy?

Answer 15

LFTs –> elevated ALT & AST

Question 16

Management of acute fatty liver of pregnancy?

Answer 16

Obstetric emergency: prompt admission and delivery of the baby.

Question 17

Name 4 pregnancy-related skin changes and rashes

Answer 17

1) Polymorphic Eruption of Pregnancy

2) Atopic Eruption of Pregnancy

3) Melasma

4) Pyogenic Granuloma

5) Pemphigoid Gestationis

Question 18

When does polymorphic eruption of pregnancy tend to appear?

Answer 18

3rd trimester

Question 19

Presentation of polymorphic eruption of pregnancy?

Answer 19

Itchy rash: usually begins on the abdomen

Particularly associated with stretch marks (striae).

Urticarial papules (raised itchy lumps)

Wheals (raised itchy areas of skin)

Plaques (larger inflamed areas of skin)

Question 20

What is the commonest skin disorder found in pregnancy?

Answer 20

Atopic eruption of pregnancy

Question 21

What does atopic eruption of pregnancy essentially refers to?

Answer 21

Eczema flare ups during pregnancy: this includes both women that have never suffered with eczema and those with pre-existing eczema.

Question 22

When does atopic eruption of pregnancy present?

Answer 22

first and second trimester of pregnancy.

Question 23

What is melasma?

Answer 23

Melasma is also known as mask of pregnancy.

It is characterised by increased pigmentation to patches of the skin on the face.

Question 24

What is pemphigoid gestationis?

Answer 24

A rare autoimmune skin condition that occurs in pregnancy.

Question 25

Typical presentation of pemphigoid gestationis?

Answer 25

An itchy red papular or blistering rash around the umbilicus, that then spreads to other parts of the body. Over several weeks, large fluid-filled blisters form.

Question 26

Definition of low lying placenta vs placenta praevia?

Answer 26

Low lying placenta –> lies within 20mm of internal cervical os

Placenta praevia –> covers internal cervical os

Question 27

What is the biggest risk factor for placenta praevia?

Answer 27

previous uterine scarring e.g. c-section

Question 28

Risk factors for placenta praevia?

Answer 28

1) previous uterine scarring e.g. c-section, previous placenta praevia

2) increased maternal age

3) multiple pregnancies

4) smoking

5) large number of previous pregnancies

6) assisted reproduction e.g. IVF

7) structural abnormalities e.g. fibroids

Question 29

At what scan is the position of the placenta assessed in pregnancy?

Answer 29

20 week anomaly scan

Question 30

What do all unresolved cases of complete praevia require?

Answer 30

C-section

Question 31

What should be avoided in placenta praevia?

Answer 31

1) vaginal & rectal exams

2) intercourse

Question 32

If placenta praevia/low lying uterus is found at anomaly scan, what is next step?

Answer 32

1) follow up scan (TVUS) at 32w to see if has resolved

2) if persistent, follow up scan (TVUS) at 36w to plan delivery

Question 33

Define antepartum haemorrhage

Answer 33

Bleeding after 28w gestation

Question 34

What happens in placental abruption?

Answer 34

Placenta detaches from the endometrium (results in haemorrhage at site of detachment).

Question 35

When is planned delivery considered in placenta praevia?

Answer 35

36-37 weeks gestation

Question 36

When should anti-D be given in any resus negative mother?

Answer 36

Within 72h of onset of bleeding

Question 37

Risk factors for placental abruption?

Answer 37

1) chorioamnionitis

2) alcohol

3) pre-eclampsia

4) overt HTN

5) smoking

6) cocaine use

7) abdo trauma

8) previous abruption

9) advanced maternal age

Question 38

How can the severity of antepartum haemorrhage be defined?

Answer 38

1) Spotting

2) Minor: <50ml

3) Major: 50-1000ml

4) Massive: >1000ml or signs of shock

Question 39

If a major or massive haemorrhage occurs in placenta praevia/placental abruption, what are the steps?

Answer 39

1) Urgent involvement of a senior obstetrician, midwife and anaesthetist

2) 2 x grey cannula

3) Bloods include FBC, UE, LFT and coagulation studies

4) Crossmatch 4 units of blood

5) Fluid and blood resuscitation as required

6) CTG monitoring of the fetus

7) Close monitoring of the mothe

Question 40

What do the fetal vessels consist of?

Answer 40

Two umbilical arteries and a single umbilical vein.

Question 41

Under normal circumstances, where does the umbilical cord containing the fetal vessels (umbilical arteries and vein) insert?

Answer 41

Inserts directly into placenta

Question 42

There are two instances when the fetal vessels can be exposed, outside the protection of the umbilical cord or placenta.

What are they?

Answer 42

1) Velamentous umbilical cord: where the umbilical cord inserts into the chorioamniotic membranes, and the fetal vessels travel unprotected through the membranes before joining the placenta.

2) An accessory lobe of the placenta (also known as a succenturiate lobe): is connected by fetal vessels that travel through the chorioamniotic membranes between the placental lobes .