Pregnancy and labour

Question 1

What are the dates of the trimesters?

Answer 1

1 = weeks 1-12
2 = weeks 13-26
3 = 26 onwards

Question 2

What is aortocaval compression?

When does it begin?

Maximal compression gestation?

What are the effects?

Answer 2

For 13w gravid uterus can press IVC and aorta against lumbar bodies.

Maximal at 36-38w and declines as foetal head descends.

Supine compresses aorta (usually partially due to aortic pressure), foetal supply and lower limbs below this. Can cause LL arterial hypotension and foetal compromise, even with normal upper limb BP. Compression engorges a zygote vein which causes back pressure on spinal canal veins.

Question 3

What is maternal supine hypotension syndrome?

How many are affected?

Effects?

Do all women get symptoms?

Answer 3

When AC compression occurs even when moved from supine to left lateral.

8% of women

Can cause maternal shock (pallor, sweating, nausea), and foetal asphyxia/ bradycardia.

Some women don’t get symptoms as they have effective epidural collaterals so don’t see a drop in venous return.