Polyhydramnios Flashcards
What is Polyhydramnios?
Too much amniotic fluid @ pregnancy
What is the numerical definition of Polyhydramnios?
Amniotic fluid index above 95% centile for GA
How does the volume of Amniotic fluid change throughout pregnancy? (3 points)
- 0-33 weeks: Increases steadily
- 33-38 weeks: Plateaus
- 38+ weeks: Declines
What is the volume of Amniotic fluid at term?
500ml
What is Amniotic fluid made up of? (3 things)
- Foetal urine output (mostly)
- Placenta contributions
- Foetal secretions
What is the pathophysiology of Polyhydramnios?
Problems w any of structures in Amniotic fluid pathway
What is the Amniotic fluid pathway? (5 steps)
- Foetus breathes + Swallows Amniotic fluid
- AF processed
- AF fills blader
- AF voided
- Cycle repeats
What are the causes of Polyhydramnios? (11 things)
- Idiopathic (60%)
- Swallowing abn (oesophageal atresia / CNS abn / muscular dystrophies)
- Duodenal atresia
- Anaemia
- Foetal hydrops
- Twin-to-Twin transfusion syndrome
- Increased lung secretions
- Chromosomal abn
- Maternal DM
- Maternal ingestion of lithium
- Macrosomia (bc big babies make more urine)
What investigation is Polyhydramnios diagnosed with?
US
What are the ways to measure AF using US to diagnose Polyhydramnios? (2 things)
- Amniotic Fluid Index (AFI) (more common)
- Maximum Pool Depth (MPD)
Apart from the Dx, why are examinations / investigations done for Polyhydramnios?
To find out the cause
What examination can you do for Polyhydramnios?
Palpate uterus to see if it feels tense
What can you check for in the US for Polyhydramnios? (3 things)
- Assess foetal size
- Assess foetal anatomy (to check for structural causes)
- Doppler (to detect foetal anaemia)
What other investigations can you do for Polyhydramnios?
- Maternal Glucose Tolerance Test (for maternal DM)
- Karyotyping (for chromosomal abn)
Is any Medical intervention routinely required for women with Polyhydramnios?
No
If Maternal symptoms of Polyhydramnios are severe (aka SOB), what can be considered?
Amnioreduction
What are the complications of Amnioreduction? (2 things)
- Infection
- Placental abruption (bc sudden decrease in intrauterine pressure)
What medication can be used enhance water retention in foetus in Polyhydramnios?
Indomethacin
What is a con of Indomethacin?
Premature closure of Ductus Arteriosus
How do you get around the con of Indomethacin?
Don’t use it beyond 32 weeks
What is special about Idiopathic Polyhydramnios?
Baby has to be examined by Paediatrician before first feed
How does the Paediatrician examine a baby with idiopathic polyhydramnios before their first feed?
Pass NG tube to ensure no Tracheoesophageal fistula / oesophageal atresia
What is Severe + Persistent + Unexplained Polyhydramnios associated with?
Perinatal mortality
Why does Severe + Persistent + Unexplained Polyhydramnios have a bad prognosis? (2 things)
- Likely presence of underlying abn / congenital malformation
- Increased incidence of preterm labour (bc of uterus over-distension)
What needs to be looked out for with Polyhydramnios DURING pregnancy?
- Malpresentation (transverse lie / breech)
- Membrane rupture
- Cord prolapse
Why are Malpresentations possible with Polyhydramnios?
Foetus has more room to move within cavity
What needs to be looked out for with Polyhydramnios AFTER pregnancy? Why?
- PPH
- Bc uterus has to contract further to achieve haemostatis
