Pregnancy

Question 1

What does progesterone during pregnancy cause?

Answer 1

• smooth muscle relaxation
• decreased GI tract motility/constipation
• increased basal temperature
• bronchodilatation
• vasodilatation
• renal tract dilatation

Question 2

How much does blood volume increase by in pregnancy at term?

Answer 2

45-50%

Question 3

Why does haematocrit decrease during pregnancy?

Answer 3

Although there is an increase in red cell mass, there is a greater increase in plasma volume resulting in a net decrease in haematocrit

Question 4

Why does cardiac output increase during pregnancy?

Answer 4

Increased stroke volume

Question 5

When does aorto caval compression become clinically significant?

Answer 5

From 20 weeks gestation onwards

Question 6

What is the normal PaCo2 in the 1st trimester?

Answer 6

It decreases to approx 4kPa due to progesterone.

Leads to respiratory alkalosis.

Question 7

What happens to FRC at term?

Answer 7

Decreased to 80% of normal.

Leads to airway closure and rapid desaturation when supine

Question 8

How much above normal does O2 consumption rise to in pregnancy?

Answer 8

35% above pre-preggo levels

Question 9

What acts as a respiratory stimulant during pregnancy?

Answer 9

Progesterone and oestrogen both do.

Question 10

What happens to gastric emptying and LOS tone during pregnancy?

Answer 10

Gastric emptying is unchanged (unless opioids given).

LOS tone is decreased due to smooth muscle relaxation.

Question 11

What % of women suffer heartburn in pregnancy?

Answer 11

75-85% due to decreased LOS tone

Question 12

When in pregnancy does an RSI become a requirement?

Answer 12

From 2nd trimester onwards

Question 13

What are oxytocics used for?

Answer 13

Eg syntocinon

Used to induce labour, to those labouring making slow progress and after delivery at C-section to ensure uterine contraction and reduce intrauterine bleeding.

They can result in hypotension/tachycardia - give slowly.

Question 14

Can warfarin cross the placenta?

Answer 14

Yes and is teratogenic so cannot be given during pregnancy.

Question 15

Can glycopyrrolate cross the placenta?

Answer 15

No it’s a quaternary amine - so charged + cannot cross the placenta

Question 16

What is tocolysis? What causes it?

Answer 16

Relaxation of uterine smooth muscle due to drug administration

• salbutamol
• terbutaline
• ritodrine
• volatile agents
• magnesium
• GTN

Question 17

What is ergometrine?

Answer 17

It’s an agonist at alpha 1 adrenoceptors, 5HT and dopaminergic recptors. It is used to aid delivery of the placenta or help gain control of PPH with an atonic uterus. Causes hypertension and should not be used in pre-eclampsia.

Question 18

What is prostaglandin F2alpha used for?

Answer 18

Uterine contraction.

Examples include carbaprost and haemabate. Side effects include bronchoconstriction, tachycardia and hypotension.

Question 19

What is pre-eclampsia?

Answer 19

Characterised by HTN and proteinuria after 20 weeks gestation. Can progress to eclampsia (fitting) or HELLP syndrome.

Occurs in 5% pregnancies.

Any fits should be treated with magnesium which then continues and fetus delivered as soon as possible,

Fits can occur up to 1 week post delivery.

Commonly results in thrombocytopenia.

Question 20

What are the ABSOLUTE contraindications to epidural anaesthesia?

Answer 20

• patient refusal
• allergy to LA
• infection over site of placement
• coagulopathy
• raised ICP
• profound hypovolaemia

Question 21

What are relative contraindications to epidural anaesthesia?

Answer 21

• bacteraemia
• neurological disorders (eg MS, syringomyelia)
• fixed cardiac output state (eg aortic stenosis, HOCM)
• previous spinal surgery
• anatomical abnormalities (eg spina bifida)