Oligohydramnios & Polyhydramnios

Question 1

What primarily contributes to the amniotic fluid contents in the first trimester?

Answer 1

Maternal plasma and transudation across the amniotic membrane.

Question 2

What primarily contributes to the amniotic fluid contents in the second trimester?

Answer 2

Fetal urine.

Question 3

What are the vital functions of amniotic fluid?

Answer 3

1. Protecting the fetus from pressure/trauma
2. Allowing limb movements
3. Supporting normal postural development
4. Permitting fetal lung expansion and development.

Question 4

How is the Amniotic Fluid Index (AFI) calculated?

Answer 4

Adding the deepest vertical pools in centimeters from four quadrants of the abdomen via ultrasound.

Question 5

What is oligohydramnios?

Answer 5

Too little amniotic fluid, where the AFI is < 5th centile for gestation (AFI < 5cm).

Question 6

What is anhydramnios?

Answer 6

The near absence of amniotic fluid.

Question 7

What are the causes of oligohydramnios related to reduced fluid production?

Answer 7

1. Renal agenesis
2. Multicystic kidneys
3. Urinary tract abnormality/obstruction
4. Fetal growth retardation (FGR) and placental insufficiency

Question 8

What is a common cause of oligohydramnios due to fluid leakage?

Answer 8

Preterm premature rupture of membranes (PPROM).

Question 9

How is oligohydramnios diagnosed?

Answer 9

1. By ultrasound showing AFI < 5th centile for gestation

and

2. Identifying potential causes like:
3. Polycystic kidneys: Enlarged kidneys with multiple cysts, non-visible bladder.
4. Renal agenesis: No renal tissue or bladder image.
5. Urinary tract obstruction: Urinary tract dilation.
6. FGR and placental insufficiency: Small-for-gestational-age baby with abnormal Doppler.

Question 10

When is oligohydramnios considered severe early onset?

Answer 10

< 24 weeks

Question 11

What are the complications of severe early-onset oligohydramnios?

Answer 11

Pulmonary hypoplasia and limb deformities

Question 12

What is the prognosis for renal agenesis or bilateral cystic kidneys?

Answer 12

Lethal prognosis.

Question 13

How severe is oligohydramnios caused by FGR/uteroplacental insufficiency?

Answer 13

Less severe, less commonly leads to limb or lung problems.

Question 14

What is polyhydramnios?

Answer 14

Excessive amniotic fluid, defined as an AFI > 95th centile for gestation (AFI > 25 cm).

Question 15

How is polyhydramnios diagnosed clinically?

Answer 15

• Severe abdominal distension with discomfort.
• Uterus larger than date (increased SFH).
• Tense and tender abdomen on palpation, with difficulty palpating fetal poles.

Question 16

What are the maternal causes of polyhydramnios?

Answer 16

1. Diabetes mellitus
2. Syphilis
3. Placental tumors (e.g., chorioangioma)
4. Arteriovenous fistula

Question 17

What are the fetal causes of polyhydramnios?

Answer 17

1. Multiple pregnancy
2. Esophageal atresia
3. Duodenal atresia
4. Anencephaly

Question 18

What is Idiopathic polyhydramnios?

Answer 18

Polyhydramnios when no specific cause is identified.

Question 19

What are the complications of polyhydramnios?

Answer 19

1. Preterm labor
2. Cord prolapse after membrane rupture

Question 20

How is maternal discomfort relieved in severe polyhydramnios?

Answer 20

Amnioreduction.

Question 21

What is the management of polyhydramnios due to maternal diabetes?

Answer 21

Prompt maternal glycemic control.

Question 22

What is the purpose of amnioreduction in severe polyhydramnios?

Answer 22

1. Relieve abdominal distension.
2. Minimize the risk of preterm labor.