Revision - Obs 4 Flashcards
Where are bile acids produced?
Produced in the liver due to breakdown of cholesterol
What complication is obstetric cholestasis associated with?
Increased risk of stillbirth
Is there a rash associated with obstetric cholestasis?
No - if a rash is present, an alternative diagnosis should be considered, such as polymorphic eruption of pregnancy or pemphigoid gestationis.
What can be given in clotting (prothrombin) time is deranged in obstetric cholestasis?
Water soluble vitamin K
How can a lack of bile salts in obstetric cholestasis lead to vitamin K deficiency?
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
Is fat soluble or water soluble vitamin K given in obstetric cholestasis?
Water soluble (won’t be able to absorb fat soluble due to lack of bile salts in obstetric cholestasis)
Monitoring of obstetric cholestasis?
Monitor of LFTs is required during pregnancy (weekly) and after delivery (after at least ten days).
Potential management of obstetric cholestasis when LFTs and bile acids are severely deranged?
Planned induction of labour at 37 weeks
When does acute fatty liver of pregnancy typically occur?
3rd trimester or period immediately following delivery.
Complications of acute fatty liver of pregnancy?
There is a high risk of liver failure and mortality, for both the mother and fetus.
What enzyme is deficient in acute fatty liver of pregnancy?
long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD)
Pathophysiology of acute fatty liver of pregnancy?
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.
Role of LCHAD enzyme?
Important in fatty acid oxidation (breaking down fatty acids to be used as fuel).
What can severe acute fatty liver of pregnancy result in?
Pre-eclampsia
Main investigation in acute fatty liver of pregnacy?
LFTs –> elevated ALT & AST
Management of acute fatty liver of pregnancy?
Obstetric emergency: prompt admission and delivery of the baby.
Name 4 pregnancy-related skin changes and rashes
1) Polymorphic Eruption of Pregnancy
2) Atopic Eruption of Pregnancy
3) Melasma
4) Pyogenic Granuloma
5) Pemphigoid Gestationis
When does polymorphic eruption of pregnancy tend to appear?
3rd trimester
Presentation of polymorphic eruption of pregnancy?
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)
What is the commonest skin disorder found in pregnancy?
Atopic eruption of pregnancy
What does atopic eruption of pregnancy essentially refers to?
Eczema flare ups during pregnancy: this includes both women that have never suffered with eczema and those with pre-existing eczema.
When does atopic eruption of pregnancy present?
first and second trimester of pregnancy.
What is melasma?
Melasma is also known as mask of pregnancy.
It is characterised by increased pigmentation to patches of the skin on the face.
What is pemphigoid gestationis?
A rare autoimmune skin condition that occurs in pregnancy.
Typical presentation of pemphigoid gestationis?
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.
Definition of low lying placenta vs placenta praevia?
Low lying placenta –> lies within 20mm of internal cervical os
Placenta praevia –> covers internal cervical os
What is the biggest risk factor for placenta praevia?
previous uterine scarring e.g. c-section
Risk factors for placenta praevia?
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
At what scan is the position of the placenta assessed in pregnancy?
20 week anomaly scan
What do all unresolved cases of complete praevia require?
C-section
What should be avoided in placenta praevia?
1) vaginal & rectal exams
2) intercourse
If placenta praevia/low lying uterus is found at anomaly scan, what is next step?
1) follow up scan (TVUS) at 32w to see if has resolved
2) if persistent, follow up scan (TVUS) at 36w to plan delivery
Define antepartum haemorrhage
Bleeding after 28w gestation
What happens in placental abruption?
Placenta detaches from the endometrium (results in haemorrhage at site of detachment).
When is planned delivery considered in placenta praevia?
36-37 weeks gestation
When should anti-D be given in any resus negative mother?
Within 72h of onset of bleeding
Risk factors for placental abruption?
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
How can the severity of antepartum haemorrhage be defined?
1) Spotting
2) Minor: <50ml
3) Major: 50-1000ml
4) Massive: >1000ml or signs of shock
If a major or massive haemorrhage occurs in placenta praevia/placental abruption, what are the steps?
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
What do the fetal vessels consist of?
Two umbilical arteries and a single umbilical vein.
Under normal circumstances, where does the umbilical cord containing the fetal vessels (umbilical arteries and vein) insert?
Inserts directly into placenta
There are two instances when the fetal vessels can be exposed, outside the protection of the umbilical cord or placenta.
What are they?
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 .
