Obstetric cholestasis Flashcards
Incidence?
In UK estimated to be 0.7% of pregnancies
Higher in women of south asian ethnicity
Definition?
Pruritus in the absence of a skin rash with abnormal liver function tests (LFTs),neither of which has an alternative cause and both of which resolve after birth
What to do with women who have persistant pruritus and normal LFTs?
Repeat LFTs in 1-2/52
Typical symptoms of obstetric cholestasis?
Pruritus in hands and feet/all over
Worse at night
Investigation of cholestasis?
Diagnosis- symptoms + abnormal LFTs/bile acids
Coagulation screen- may need to give vitamin K
Diagnosis of exclusion, so also need to do:
- Viral hepatitis screen
- Consider Liver USS
- Liver autoimmune screen for primary biliary cirrhosis (anti-smooth muscle and anti-mitochondrial antibodies)
- Exclude PET and acute fatty liver of pregnancy
Monitoring of cholestasis
- Weekly LFTs +/- coag screen depending on severity
Postnatal considerations
- Check PN LFTs 10/7 later
- Sx and bloods should return to normal by 6/52 - if not then an alternative cause should be considered
- Discussion re:
- Risk of recurrence in future pregnancies (45-90%)
- Contraceptive advice- avoid COCP
Fetal risks
- Stillbirth - current obstetric management suggests that still birth rate is now closer to the rate for the general population. Higher risk of still birth if bile salts >100 (2019 lancet), >40 still considered to also be higher risk.
- Prematurity- iatrogenic and idiopathic
- Meconium liqour
- Fetal distress in labour
Maternal risks
- PPH
- CS for fetal distress
How to class severity of OC?
Severe = bile salts >40 Mild = bile salts <20
Can fetal death be predicted and prevented?
- In vitro evidence that level of bile salts may play a role in fetal demise- either through arrhythmia or placental vessel spasm
- In real life- difficult to know exactly how this affects the fetus. May be due to maternal serum bile salt level or fetal bile salt level.
- Link found with bile salts >40 and: passage of meconium, abnormal CTG, non-fatal fetal asphyxia events, prematurity
- CTG and growth scans do not identify babies at risk of stillbirth as fetal death is usually sudden
Timing of delivery
- Consider IOL from 37+0/40
- No clear evidence regarding still birth risk, may be increased fetal risk from IOL at 37/40
- Women with higher bile salts levels and more deranged LFTs may benefit more from IOL around 37/40
CMDHB guideline since Lancet study:
Bile salts > 100 or ALT > 200: Timing of delivery to be individualised.
Bile Salts > 40 or worsening liver functions: Offer IOL at 38 weeks.
Bile Salts =< 40: Offer IOL at 40 weeks
http: //www.edu.cdhb.health.nz/Hospitals-Services/Health-Professionals/maternity-care-guidelines/Documents/GLM0005-Cholestasis-Obstetric.pdf
https: //www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31877-4/fulltext
Treatment for OC
Definitive treatment is delivery
- UDCA found to reduce itching although results variable in studies. No proven benefit to outcome for fetus.
- Women may benefit from emollient
- Vitamin K if PT prolonged (5-10mg a day)
Physiological rationale for the use of vitamin K?
In OC there is a decreased absorption of fats from GI tract due to reduction in excretion of bile salts
Leads to reduction in absorption of fat soluble vitamins eg. vitamin K
Vitamin K required for the manufacture of coagulation factors 11,V11, 1X and X
In a small study, PPH found to be more common in those who didn’t take vitamin K than those who did
Oral vitamin K is in a water soluble form
Baby- should have vitamin K
Neonatal concerns re use of vitamin K?
Historic evidence suggesting higher rates of jaundice and kernicterus in babies who received high doses of vitamin K - unlikely to be significant in low oral doses of vitamin K given for OC/in babies with normal vitamin K prophylaxis
