Oligohydramnios

Question 1

What is Oligohydramnios?

Answer 1

Low level of amniotic fluid in pregnancy

Question 2

What is the numerical definition of Oligohydramnios?

Answer 2

Amniotic fluid index below 5^th centile for GA

Question 3

What percentage of pregnancies does Oligohydramnios affect?

Answer 3

4.5%

Question 4

What can cause Oligohydramnios pathophysiologically speaking? (3 things)

Answer 4

1. Reduced production of urine
2. Blocked output from foetus
3. Membrane rupture (fluid leaks)

Question 5

What are the causes of Oligohydramnios? (7 things)

Answer 5

1. Placental insufficiency
2. Renal agenesis (aka Potters syndrome)
3. Non-functioning foetal kidneys
4. Obstructive uropathy
5. Preterm prelabour membrane rupture
6. Chromosomal abn
7. Viral infections (can also cause Polyhydramnios)

Question 6

How does Placental insufficiency cause Oligohydramnios? (2 steps)

Answer 6

1. Blood flow redistributed to foetal brain (instead of abdomen + kidneys)
2. Poor urine output

Question 7

What investigation is Oligohydramnios diagnosed with?

Answer 7

US

Question 8

What are the ways to measure AF using US to diagnose Polyhydramnios? (2 things)

Answer 8

1. Amniotic Fluid Index (AFI) (more common)
2. Maximum Pool Depth (MPD)

Question 9

What might you also see in the US that might suggest Oligohydramnios?

Answer 9

Small foetus (bc placental insufficiency, which is a cause of Oligo)

Question 10

What CF in the Hx might suggest Oligohydramnios?

Answer 10

Leaking fluid + feeling damp all the time (described as new urinary incontinence)

Question 11

What CF @ examination might suggest Oligohydramnios?

Answer 11

Palpable foetal parts

Question 12

If Oligohydramnios is caused by Ruptured Membrane, what is gonna happen next?

Answer 12

Labour within 24-48 hours

Question 13

If Oligohydramnios is caused by PRETERM Ruptured Membrane (b4 37 wks), and labour doesn’t start automatically, what should you do?

Answer 13

Consider labour induction @ 34-36 weeks

Question 14

What should you also give in the case of Oligohydramnios caused by PRETERM Ruptured Membrane? (2 things)

Answer 14

1. Steroids course (to aid foetal lung dev)
2. Abx (reduce inf risk)

Question 15

If Oligohydramnios is caused by Placental Insuff, what does the delivery timing depend on? (3 things)

Answer 15

1. Foetal growth rate
2. Umbilical artery + Middle cerebral artery Doppler scans
3. Cardiotocography

Question 16

When should babies with Placental insuff be delivered by?

Answer 16

Before 36/37 wks

Question 17

Which trimester does Oligohydramnios have a poor prognosis?

Answer 17

In 2^nd trimester

(bc usually due to premature ruptured membrane)

Question 18

What are the complications of Oligohydramnios? (2 things)

Answer 18

1. Muscle contractures –> disability after birth
2. Pulmonary hypoplasia (fatal)

Question 19

Why can foetus develop Muscle contractures bc Oligohydramnios? (2 points)

Answer 19

1. Amniotic Fluid usually allows foetus to move limbs in utero (basically exercises)
2. Without this –> muscle contractures

Question 20

Can muscle contractures bc Oligohydramnios be resolved with Physio?

Answer 20

Maybe