Medications used in Labour

Question 1

Contraindications to induction of labour

Answer 1

Absaloute 
- abnormal lie
- known pelvic obstruction such as tumour or large ovarian cyst
- placenta praevia
- foetal distress
Relative 
- Previous C section (risk of rupture of uterus due to scar)
- asthma

Question 2

Why is asthma a relative contraindication to IOL?

Answer 2

Prostaglandins (including PGE2 analogues) can cause respiratory smooth muscle contraction

Question 3

Function of prostaglandin analogues

Answer 3

Encourage cervical dilatation and effacement = ripen the cervix

Question 4

Possible results of prostaglandin analogues

Answer 4

Contractions
Severe contractions/hypertonic uterus 
Pyrexia
Nausea and vomiting
Bowel upset
Hypotension

Question 5

Function of oxytocin

Answer 5

Initiates uterine contraction by attaching to uterine oxytocin receptors; increases the frequency and force of contractions

Question 6

When is oxytocin used in IOL?

Answer 6

After prostaglandin treatment once amniotomy Is performed

Question 7

Risks of oxytocin in IOL

Answer 7

Uterine hypertonicity
Hypotension
Hyponatraemia

Question 8

When is augmentation of labour required?

Answer 8

When contractions reduce in frequency and strength in active labour, even after spontaneous onset of labour

Question 9

What is used in the augmentation of labour?

Answer 9

Oxytocin

Question 10

What does active management of stage 3 of labour involve?

Answer 10

1. Early clamping and cutting of umbilical cord
2. Use of uterotonic medications (pharmacological management)
3. Delivery of the placenta by controlled cord traction

Question 11

Medications used in the active management of the third stage

Answer 11

Syntometrine

Oxytocin

Question 12

What is syntometrine?

Answer 12

A combination of oxytocin and ergometrine

Question 13

What does ergometrine do?

Answer 13

Causes smooth muscle (uterine) contraction

Question 14

Management of PPH

Answer 14

Physical interventions
- rubbing up a contraction 
- bimanual compression 
Surgical interventions
Pharmacological interventions
- Oxytocin 
- syntometrine or ergometrine alone
- carboprost 
- misoprostol 
- tranexamic acid (if others arents working)

Question 15

Function of tocolysis

Answer 15

To inhibit uterine contractions

Question 16

When in preterm labour, what must be given ASAP?

Answer 16

Steriods

Question 17

Why would tocolysis be used?

Answer 17

1. Facilitate transfer of women in labour to another hospital, particularly in a hospital with an appropriate neonatal unit
2. To give steroid treatment enough time to work (2 doses 24 hours apart)

Question 18

Tocolysis drugs

Answer 18

CCBs e.g. nifedipine, orally
Oxytocin receptor antagonist e.g atosiban, IV
Beta 2 agonists e.g. salbutamol
Indomethacin

Question 19

Tocolysis is ocassionally indicated if….

Answer 19

Foetal distress and need for emergency C section
Obstructed labour
Hypertonic uterus causing foetal distress

Question 20

If emergency tocolysis needed, e.g. in obstructed labour or foetal distress etc, what can be used?

Answer 20

GTN

Terabutaline

Question 21

Pregnant women may be on anti-hypertensives for which conditions?

Answer 21

Pre-existing HTN
Pregnancy induced HTN
Pre-eclampsia

Question 22

Special hypertensives used in pregnancy

Answer 22

Methyldopa
Hydralazine
Combined alpha and beta blockers e.g. labetolol

Question 23

What is the first line drug for HTN in labour?

Answer 23

Labetolol

Question 24

What is used to treat women with symptomatic pre-eclampsia, and thought to be at risk of eclampsia, to prevent or treat seizures?

Answer 24

IV magnesium sulphate

Question 25

Antihypertensives contraindicated in pregnancy

Answer 25

ACE inhibitors ARBs Spironolactone

Question 26

Analgesics allowed in pregnancy

Answer 26

``` Paracetomal Dihydrocoedine/codeine Entonox "gas+air" Opiates (when pain is more severe) Local analgesia ```

Question 27

Signs of local anaesthetic toxicity

Answer 27

``` Perioral tingling Paraesthesia Confusion Drowsiness Light headedness Seizures Coma, CR arrest and can be lethal ```

Question 28

Contraindications of an epidural anaesthetic

Answer 28

``` Thrombocytopenia Coagulopathy Raised ICP Local sepsis Septic shock Allergy to local anaesthetic Lack of patient consent Anticoagulants within 12 hours of insertion ```

Question 29

Advantages of epidural anaesthetic

Answer 29

Effective during labour Can be topped up if need to go to theatre for instrumental delivery or C section Effective after delivery if need repair of vaginal tears or manual removal of placenta (MROP) Best for baby Can prevent further raised BP in pre-eclampsia

Question 30

Disadvantages of epidural anaesthesia

Answer 30

Can fail to provide adequate analgesia (1 in 10 need resisted) Causes hypotension (1 in 50, dose dependent) Reduces womens mobility Dural puncture (1 in 100) leading to headache Epidural haematoma/abscess (<1 in 10000) Risk of respiratory depression (1 in 100 to 1 in 1000 chance) Risk of neurological deficits (1 in 10000 to 1 in 40000 chance)

Question 31

In spinal anaesthetic, where is the medication injected into?

Answer 31

The subarachnoid space

Question 32

Advantages of spinal anaesthetic

Answer 32

Gives dense, anaesthetic bilateral block | Patient can stay awake and protect own airway during an operation

Question 33

Disadvantages of spinal anaesthetic

Answer 33

``` 2-3% risk of inadequate pain relief Shorter duration -> can wear off Causes hypotension Needs catheter Risk of dural puncture + post dural puncture headache Severe pruitis or nausea and vomiting Small risk of nerve damage ```

Question 34

Why can general anaesthesia be more difficult in pregnancy?

Answer 34

Increased risk of aspiration of stomach contents | More difficult to intubate pregnant women