Poly/Oligohydramnios Flashcards
Define Oligohydramnios
Reduced amniotic fluid due to reduce urine production by the fetus.
AFI <8cm (<5th centile)
DVP <2cm
Causes of less liquor - Fetal
'’DROP the liquor’’
Duodenal Atresia
Renal Agenesis
Obstruction of urethra
Pyloric Stenosis
Causes of less liquor - Maternal
DIRT PP
TORCH
ROM
Idiopathic
Drugs (ACE + NSAIDS)
Placental insufficiency
PET
Clinical features of oligohydramnios
- SFD
- Gush or leaking
- Reduced FM
- HTN
Clinical Exam of Oligohydramnios
SFH
Palpation for presentation + lie
Auscultate
Speculum
Vitals
Investigations for Oligohydramnios
Amnisure for PPROM
US - AFI and DVP
Doppler - umbilical artery
US for growth of baby
Anomaly scan + amniocentesis or CVS
Complications of Oligohydramnios
- Prematurity
- Pulmonary Hypoplasia
- Fetal demise
- Emergency delivery
- Cord prolapse
DDx of oligohydramnios
- Small for Dates
- IUGR
- PROM
- PET
Define Polyhydramnios
An excessive amount of amniotic fluid due to excessive urine production by the fetus.
- AFI >24cm, 95th centile
- DVP >8cm
Causes of Polyhydramnios
AIRMAT
Anemia
Infection
Rhesus incompatibility
Maternal GDM
Abnormalities (Down syndrome, Potter Syndrome, esophageal or duodenal atresia
Twin-twin transfusion syndrome
Clinical Features of Polyhydramnios
LFD
RFM
Breeathlessness
Dyspnoea
Hemorrhoids
Complications of Polyhydramnios
PTL
Passed away
PPROM
PPH
Presentation - unstable
Prolapse cord
Placental Abruption
Management of polyhydramnios
- Pain relief
- Steroids
- Serial growth scans
- Fetal movements
- DVT risks and prophylaxis
- Deliver by term
Assessment and Investigations
- OGTT
- TORCH screening
- Bloods: FBC, AntiD, Rhesus Disease ABs
- US scan for fetal size
- Amniocentesis or CVS for genetics
- ? Electrophoresis
- Parvovirus serology - IgG and IgM
What is the difference between small for gestational age and small for dates?
SFGA = a babys weight that is below the 10th percentile for their gestation
SFD = a baby that is smaller than expected for their gestation and can be divided into symmetrical or asymmetrical.
What are the common causes of symmetrical small-for-dates growth restriction?
- Constitutional (small mum and baby)
- Congenital (TORCH)
- Chromosomal abnormalities
- Incorrect dates
What are the common causes of asymmetrical small-for-dates growth restriction?
- Placental insufficiency
- GDM
- HTN
How does utero-placental insufficiency contribute to asymmetrical small-for-dates growth?
Brain sparing effect - lack of blood flow and oxygen to the fetus causes an asymmetrical growth restriction between head and body where the head is disproportionate to the abdomen.
What are the three main causes of reduced amniotic fluid volume?
- ROM
- Placental insufficiency
- Fetal abnormalities (renal agenesis, ARPCKD, Urethral obstruction)
How is oligohydramnios (reduced amniotic fluid) diagnosed using ultrasound?
- Divide the abdomen into 4 quarters and AFI and DVP are assessed
- AFI <8cm and DVP <2cm
What are the normal values for amniotic fluid index (AFI) and deepest vertical pool (DVP)?
- AFI 8-20
- DVP 2-8
How can post-dates pregnancy lead to reduced amniotic fluid levels?
Post dates increases the risk of placental insufficiency which leads to reduced amniotic fluid production and increased risk of meconium aspiration.
What is the clinical significance of an amniotic fluid index (AFI) of less than 8 cm?
increases the risk of
1) IUGR2
2) placental insufficiency
3) cord compression.
What ultrasound measurements are used to assess fetal growth?
- Head circumference
- BPD
- OFD
- Abdominal circumference
- Femur length
What is the importance of the umbilical artery Doppler in assessing fetal well-being?
It measures the resistance to blood flow and indicates placental function and fetal oxygenation. Increased resistance, absence or reversed indicates fetal distress.
What is the significance of a raised Doppler waveform in the umbilical artery?
- Raised Doppler indicates increased resistance to blood flow, suggesting placental insufficiency, which can lead to fetal growth restriction and hypoxia.
- Absent = No forward flow during diastole. placental insufficiency
- Reversed = Backward flow of blood during diastoles. Indicates fetal compromise.
- Both require immediate delivery.
