Medical problems in pregnancy

Editor – We were interested to read the article by Bhaskar

Narayan and Catherine Nelson-Piercy, ‘Medical problems in pregnancy’.¹ However, in the neurology section we felt that a couple of important safety issues were not addressed clearly enough.

For headache, from an investigation point of view, we have noticed on ward referrals that fundoscopy may be omitted. This is particularly useful in this group given sinus thrombosis is high on the list of differentials.

Additionally, migraine treatment is complex and aspirin is useful, but it should not be used in the third trimester because of its impact on closure of the ductus arteriosus, as noted in the British national Formulary (BNF) as well as elsewhere.²

Likewise, propranolol is listed as causing intrauterine growth restriction in the British National Formulary – ‘Beta-blockers may cause intra-uterine growth restriction, neonatal hypoglycaemia, and bradycardia; the risk is greater in severe hypertension’ – and www.drugs.com also warns that ‘this drug is only recommended for use during pregnancy when there are no alternatives and the benefit outweighs the risk’ and ‘beta blockers may cause decreased placental perfusion, fetal and neonatal bradycardia, and hypoglycemia’.

Furthermore, NICE guidelines counsel against opiates for migraine because they are ineffective – ‘Do not offer ergots or opioids for the acute treatment of migraine’.³

Topiramate and valproate are both licensed for migraine treatment but should not be offered to pregnant patient as they are teratogenic.

Epilepsy in pregnancy is another complex issue as described; lamotrigine, carbamazepine and levetiracetam account for over 80% of AEDs used in pregnancy. Phenytoin has been falling in use, with less than 2% of women with epilepsy on the register in 2006 using it. With regard to lamotrigine, the commonest drug used, it is known that levels tend to fall in the third trimester; the findings on the register show that some authorities tend to obtain a single drug level early in pregnancy in controlled patients only reassessing this if there is loss of seizure control, rather than monitoring throughout.