Poly/olighohydramnios Flashcards
What makes up the majority of amniotic fluid after 20 weeks
Foetal urine - volume depends on
- Urine production
- Foetal swallowing
- Absorption
At what gestation is the volume of amniotic fluid at its highest?
24-36 weeks
How is the volume of amniotic fluid measured?
USS:
- Deepest vertical pool (should be 2-8cm)
- Amniotic fluid index (AFI - should be 8-22cm)
Causes of oligohydramnios?
Leakage of amniotic fluid (SROM)
Reduced foetal production:
- IUGR
- Foetal renal failure/abnormality
Obstruction of foetal urine output - abnormalities such as posterior urethral valves
Complications of oligohydramnios
PROM –> delivery +/- infection
IUGR
Reduced volume –>:
- lung hypoplasia if <22 weeks (v. poor prognosis)
- Talipes if prolonged
Investigation
USS of foetus and doppler
Speculum - look for SROM
If SROM - FBC, CRP and vaginal swabs (infection)
Management
SROM >37 weeks –> induce labour
SROM <37 weeks - prophylactic oral erythromycin, monitor, CTG
IUGR - depends on umbilical artery doppler + CTG
Refer to fetal medicine centre (fetal tract abnormality)
Causes of polyhydramnios
Idiopathic (50%) - usually mild
Maternal = DM (25%)
Foetal:
- Twin-twin transfusion syndrome (10%)
- Foetal hydrops/anaemia (10%)
- GI tract abnormality (e.g. duodenal atresia in trisomy 21) - can’t swallow amniotic fluid
- Foetal neurological/ muscular dystrophy - can’t swallow fluid
Complications of polyhydramnios
Preterm delivery (uterus stretches too much)
Malpresentation
Maternal discomfort
Investigations for polyhyrdramnios
Exclude maternal DM - GTT
USS
Management of polyhydramnios
Treat cause e.g. transfusion for anaemia foetalis hydrops
Severe - amnioreduction
Assess risk of delivery (cervix via TVS)
- give steroids if <34 weeks
- induction if foetal distress
