8A) Antenatal Care: Polyhydramnios

Question 1

Incidence of polyhydramnios

Answer 1

1%

Question 2

Classification of polyhydramnios

Answer 2

Mild: AFI 25-30cm
Moderate: AFI 30-35cm
Severe: AFI >35cm

Question 3

DVP which is classed as polyhydramnios?

Answer 3

> 8cm

Question 4

What proportion of polhydramnios cases are unexplained?

Answer 4

50-60%

Question 5

When does amniotic fluid volume reach its peak?

Answer 5

33-38 weeks

Question 6

Mean volume of amniotic fluid

Answer 6

600-800mL

Question 7

What is the increase in perinatal morbidity and mortality with polyhydramnios?

Answer 7

2-5 x increased

Question 8

How to investigate polyhydramnios?

Answer 8

USS for fetal weight, anomalies, movement and stomach/bladder.
Maternal investigations - GTT, TORCH, Red cell antibodies.

If remains unexplained & severe - refer to FMU and consider amniodrainage.
If remains unexplained & moderate/severe - serial growth scans, TVS for cervical length and no need for early IOL.

Question 9

Risk of complications with amnioreduction

Answer 9

1.5%

Question 10

Risk of major congenital anomaly with polyhydramnios

Answer 10

1% mild, 2% moderate, 11% severe (even with normal USS)

Question 11

Risk of chromosomal abnormalities with polydramnios

Answer 11

If USS shows abnormalities - 10%.

If USS normal - 1%.

Question 12

Risk of aneuploidy if persistent polyhydramnios

Answer 12

10-20%.