Prescribing in Pregnancy

Question 1

Heparin can cross the placenta. True/false?

Answer 1

False - cos large molecular weight

Question 2

Most drugs can cross the placenta.

What drugs can cross the placenta more quickly?

Answer 2

Small, lipid-soluble drugs

Question 3

Drugs undergo absorption, distribution, metabolism and elimination. List 5 factors in pregnancy that can affect these processes.

Answer 3

Absorption can be affected by morning sickness, increased plasma volume and fat stores , decreased protein binding so increased free drug, increased liver metabolism of some drugs e.g. phenytoin, elimination of renally excreted drugs increases due to increased eGFR

Question 4

Give 2 examples of drugs you may need to check concentrations of and alter dose during pregnancy and after delivery.

Answer 4

Lithium and digoxin

Question 5

At what point of pregnancy may some pregnant women be more sensitive to antihypertensives?

Answer 5

In 2nd semester BP can dip so need to watch for hypotension if on antihypertensives

Question 6

When should folic acid be taken during pregnancy and why?

Answer 6

3 months before conception and for first 3 months of pregnancy to prevent neural tube defects

Question 7

When is the period of greatest teratogenic risk? Avoid all drugs at this point if possible unless maternal benefit outweighs risk to foetus

Answer 7

4th - 11th week

Question 8

ACEi and ARBs are teratogenic, what defect can they cause?

Answer 8

renal hypoplasia

Question 9

Antiepileptics are teratogenic and can cause what kind of defects?

Answer 9

cardiac, facial, limb or neural tube defects

Question 10

Lithium is teratogenic and can cause what kind of defects?

Answer 10

Cardiovascular defects

Question 11

Methotrextate is teratogenic and can cause what kind of defects?

Answer 11

Skeletal defects

Question 12

Retinoids are teratogenic, what kind of defects can they cause?

Answer 12

ear, cardio or skeletal

Question 13

Warfarin is teratogenic, what kind of defects can it cause when given in early pregnancy? What adverse effect can it cause when given in late pregnancy?

Answer 13

Early pregnancy: limb and facial defects, late pregnancy: risk of haemorrhage during delivery

Question 14

What effects can drug exposure cause in 2nd and 3rd trimesters?

Answer 14

intellectual impairment and behavioural abnormalities as

Question 15

List some adverse effects on labour caused by drugs.

Answer 15

progress of labour, adaptation of foetal circulation (e.g. premature ductus arteriosus closure), suppression of foetal systems (e.g. opiates), bleeding (e.g. warfarin)

Question 16

List 2 drugs that can cause the baby to have withdrawal syndrome after delivery?

Answer 16

opiates and SSRIs

Question 17

Incidence of congenital malformations is higher in untreated women with epilepsy than women without epilepsy. True/false?

Answer 17

True

Question 18

There are increased seizures in 10% of women during pregnancy. What are frequent seizures during pregnancy associated with? (5)

Answer 18

lower verbal IQ in child, hypoxia, bradycardia, antenatal death and maternal death

Question 19

What 2 antiepileptic drugs should be avoided during pregnancy and what defects can they cause?

Answer 19

valproate - can cause spina bifida and anencephaly, and phenytoin - can cause cleft lip and palate

Question 20

Antiepileptics increase risk of congenital malformations however so does epilepsy in itself and seizures are also bad. How should epilepsy treatment be managed in pregnancy?

Answer 20

just one type of drug if possible, folic acid 5mg daily

Question 21

How is diabetes managed in pregnancy?

Answer 21

Insulin safe but need very good control as poor control increases risk of congenital malformations and intra-uterine death

Question 22

What diabetes drugs are not safe in pregnancy?

Answer 22

Sulphonyureas

Question 23

Which drugs should be used to treat hypertension in pregnancy and which avoided?

Answer 23

Use: labetalol, methyldopa,, nifedipine MR

DON’T USE: ACEi/ARB, beta blockers can inhibit foetal growth

Question 24

What is safest drug for N&V during pregnancy?

Answer 24

Cyclizine

Question 25

What is safest drug for UTI during pregnancy?

Answer 25

Nitrofurantoin, cefalexin, 3rd trimester trimethoprim

Question 26

What is safest drug for pain during pregnancy?

Answer 26

paracetamol

Question 27

What is safest drug for heartburn during pregnancy?

Answer 27

antacids

Question 28

VTE is leading cause of maternal death so those with 2 or more risk factors should receive:

Answer 28

thrombophylaxis with LMWH at delivery and up to 7 days post-partum

Question 29

List 6 risk factors for VTE in pregnancy

Answer 29

obesity, age >35, smoking, para >3, previous DVT, C-section

Question 30

Most drugs enter breast milk, especially ___ ____ & __ ____ ___.

Answer 30

small molecules & fat soluble drugs.

Question 31

The following drugs can cause what adverse effect when taken when breastfeeding? Amiodarone, cytotoxics, benzodiazepines, bromocriptine

Answer 31

amiodarone - neonatal hypothyroidism, cytotoxics - bone marrow suppression, benzos - drowsiness, bromocriptine - suppresses lactation

Question 32

What drug can cause cleft lip and palate?

Answer 32

phenytoin (antiepileptic)

Question 33

Which drug can cause vaginal adenocarcinoma in female offspring?

Answer 33

stilbestrol