Meds used in antenatal care

Question 1

How do NSAIDs work generally and why is the thing they inhibit important?

Answer 1

Prostaglandin inhibitors

Prostaglandins are important for maintaining the ductus arteriosus (NSAID use causes premature closure- this leads to volume overload in foetal pulmonary circulation and persistent pulmonary hypertension)

Prostaglandins help soften the cervix and stimulate uterine contraction. Inhibition through NSAID use will delay labour

Question 2

In what circumstances may NSAIDs be used in pregnancy

When should NSAIDs deffo be avoided in pregnancy?

Answer 2

Only when absolute necessary e.g. RA

Particularly avoided in 3rd trimester as they can close the ductus arteriosus and delay labour

Question 3

Clinical indications for beta blockers: generally speaking

What condition is it used to manage

What is the first line B-blocker in pregnant women? 2nd line

Answer 3

Commonly used for hypertension, cardiac conditions and migraine

HTN caused by pre-eclampsia

Labetalol
Nifedipine/ Methyldopa (if patient is an asthmatic, has uncontrolled HF)

Question 4

Labetalol (beta blocker) SEs by system:

Neurological 
Skin 
GI 
Urological 
Neuropsychiatric 
Other

Answer 4

Neurological — tiredness, weakness, headache.
Skin — rashes, tingling scalp
Gastrointestinal — epigastric pain, nausea, vomiting, liver damage.
Urological — difficulty in micturition.
Neuropsychiatric — depressed mood.
Other — postural hypotension, nasal congestion, sweating.

Question 5

When is labetalol contraindicated

Answer 5

Asthma.
Uncontrolled heart failure.
Cardiogenic shock
Phaeochromocytoma
Metabolic acidosis.
Bradycardia.
Hypotension

Question 6

Labetalol side effects on foetus

Labetalol dose

Answer 6

Fetal growth restriction
Hypoglycaemia in the neonate
Bradycardia in the neonate

100mg BID: intervals can be increased fortnightly

Question 7

How do ACEIs and ARBs work generally speaking?

What can happen in the foetus aar of their use?

Answer 7

ACE- Stops ACE enzyme from converting Angiotensin 1 to Angiotensin 2
ARBs work by blocking AT1 receptors, which are found in the heart, blood vessels and kidneys. Reduces the action of angiotensin 2 to prevent blood vessel constriction

These drugs can cross the placenta and enter the foetus. Here they mainly affect the kidneys, and reduce the production of urine (and therefore amniotic fluid)
Also causes hypocalvaria, which is an incomplete formation of the skull bones.

Question 8

Side effects on the foetus when ACEIs and ARBs are used in pregnancy

Answer 8

Oligohydramnios (reduced amniotic fluid)
Miscarriage or fetal death
Hypocalvaria (incomplete formation of the skull bones)
Renal failure in the neonate
Hypotension in the neonate

Question 9

What does the use of opiates in pregnancy cause?

What is the name of this condition and how does it present

Answer 9

The use of opiates during pregnancy can cause withdrawal symptoms in the neonate after birth

Neonatal abstinence syndrome (NAS). NAS presents between 3 – 72 hours after birth with irritability, tachypnoea (fast breathing), high temperatures and poor feeding.

Question 10

Clinical indications of warfarin generally speaking

Why is warfarin avoided in pregnant women? What does it cause?

Answer 10

Warfarin may be used in younger patients with recurrent venous thrombosis, atrial fibrillation or metallic mechanical heart valves

It crosses the placenta and is considered teratogenic in pregnancy, therefore it is avoided in pregnant women. Warfarin can cause:
Foetal loss
Congenital malformations, particularly craniofacial problems
–Inhibition of osteocalcin causes lower bone growth
Bleeding during pregnancy, postpartum haemorrhage, foetal haemorrhage and intracranial bleeding

Question 11

What does use of sodium valproate cause in pregnancy

What needs to be confirmed before sodium valproate can be used

Answer 11

Neural tube defects and developmental delay.

Strict rules for avoiding sodium valproate in girls or women unless there are no suitable alternatives and strict criteria are met to ensure they do not get pregnant

Question 12

Side effects of sodium valproate generally speaking

Answer 12

VALPROATE! 
Vomiting 
Alopecia 
Liver toxicity 
Pancreatitis and decreased platelets 
Rash (allergy) 
Obesity 
Anorexia 
Tremor/ teratogenic
Enzyme inhibitor: lowers seizure threshold

Question 13

Lithium clinical indications generally speaking

Answer 13

Lithium is used as a mood stabilising medication for patients with bipolar disorder, mania and recurrent depression

Usually avoided unless other options have failed

Question 14

When should Lithium be avoided in pregnancy (and which trimester )

Answer 14

First trimester

Assoc with Congenital cardiac abnormalities
Assoc with Ebstein’s anomaly, where the tricuspid valve is set lower on the right side of the heart (towards the apex), causing a bigger right atrium and a smaller right ventricle.

Question 15

How should lithium use be monitored ?

Is lithium safe in breastfeeding

Answer 15

Nice: every 4 weeks
From week 36 onwards- every week

No, it enters the milk and is toxic to the infant

Question 16

Danger of SSRIs in pregnancy

Give examples of SSRIs in pregnancy

Answer 16

SSRIs can cross the placenta into the foetus

First-trimester use has a link with congenital heart defects
First-trimester use of paroxetine has a stronger link with congenital malformations
Third-trimester use has a link with persistent pulmonary hypertension in the neonate
Neonates can experience withdrawal symptoms, usually only mild and not requiring medical management

Examples: Citalopram and Sertaline

Sertraline and Paroxetine first line SSRIs in pregnancy

Question 17

Isotretinoin use

What caution should be exercised with Isotretinoin ?

Answer 17

Retinoid medication used to treat severe acne
Should be prescribed and monitored by a dermatologist

Isotretinoin is highly teratogenic, causing miscarriage and congenital defects. Women need very reliable contraception before, during and for one month after taking isotretinoin.