Drugs in labour

Question 1

Where is oxytocin released

Answer 1

Posterior pituitary gland

Question 2

Where is oxytocin produced

Answer 2

Hypothalamus

Question 3

Role of oxytocin

Answer 3

Oxytocin stimulates the ripening of the cervix and contractions of the uterus during labour and delivery.

It also plays a role in lactation during breastfeeding - let down reflex

Question 4

Role of oxytocin infusions

Answer 4

Induce labour

Progress labour

Improve the frequency and strength of uterine contractions

Prevent or treat postpartum haemorrhage

Question 5

Atosiban

Answer 5

Oxytocin receptor antagonist - alternative to nifedipine for tocolysis in premature labour

Question 6

Ergometrine

Answer 6

Stimulates smooth muscle contraction in the uterus and blood vessels.

Useful for delivery of the placenta and to reduce postpartum bleeding.

Question 7

When is ergometrine used

Answer 7

Third stage of labour (delivery of the placenta)

Postpartum to prevent and treat postpartum haemorrhage.

Only used after delivery of the baby, not in the first or second stage.

Question 8

Side effects of ergometrine

Answer 8

Hypertension - vasoconstriction

Diarrhoea and vomiting - vasoconstriction of GI vessels

Angina

Question 9

Cautions for ergometrine

Answer 9

Avoided in eclampsia

Used with significant caution in patients with hypertension

Question 10

Syntometrine

Answer 10

Oxytocin and ergometrine - prevention or treatment of postpartum haemorrhage

Question 11

Role of prostaglandins

Answer 11

Stimulate contraction of the uterine muscles

Ripen the cervix before delivery

Question 12

Dinoprostone use

Answer 12

Prostaglandin E2

Used for induction of labour

Question 13

Forms of dinoprostone

Answer 13

Vaginal pessaries (Propess)
Vaginal tablets (Prostin tablets)
Vaginal gel (Prostin gel)

Question 14

Side effect of dinoprostone

Answer 14

Hypotension - causes vasodilation

Question 15

Nifedipine

Answer 15

CCB used in tocolysis - inhibits uterine contractions therefore delaying onset of labour

Reduces blood pressure in hypertension and pre - eclampsia - vasodilator

Question 16

Terbutaline

Answer 16

Beta-2 agonist - acts on the smooth muscle of the uterus to suppress uterine contractions.

Used for tocolysis in uterine hyperstimulation

Question 17

Carboprost

Answer 17

Synthetic prostaglandin analogue - stimulates uterine contraction.

Intramuscular injection in postpartum haemorrhage, where ergometrine and oxytocin have been inadequate.

Question 18

Caution for carboprost

Answer 18

Avoided or used with particular caution in patients with asthma

Can cause a potentially life-threatening exacerbation of the asthma

Question 19

Tranexamic Acid

Answer 19

Antifibrinolytic medication that reduces bleeding

Binds to plasminogen and prevents it from converting to plasmin. Plasmin dissolves the fibrin within blood clots.

Used in the prevention and treatment of postpartum haemorrhage

Question 20

Misoprostol

Answer 20

Prostaglandin analogue - increases uterine contractions

Medical management in miscarriage, to help complete the miscarriage

Used for abortions and induction of labour after intrauterine fetal death

Question 21

Mifepristone

Answer 21

Mifepristone - anti-progestogen

Prevents the progression of pregnancy and ripening the cervix.

Used alongside misoprostol for abortions, and induction of labour after intrauterine fetal death.