Multiple sclerosis - Disorders of the central Nervous System

Pregnancy raises complex issues for women with multiple sclerosis. Preconceptual considerations include the small risk (approximately 3 per cent) of their child inheriting the disease and the practical burdens that child care imposes upon a mother with existing and potentially progressive disability. Several epidemiological studies have shown that the incidence of relapses of multiple sclerosis falls during pregnancy itself, with a compensatory rise in the puerperium (with between 20 and 40 per cent of women reporting an exacerbation of symptoms.) It has been suggested that this reflects the production of pregnancy-associated proteins with immunosuppressive properties, such as α-fetoprotein, and changes in T-lymphocyte subsets. There is no evidence of any long-term detrimental effect on disability, and no evidence of any adverse effect from epidural anaesthesia or breastfeeding.

Relapses in pregnancy are treated in the normal way, with rest supplemented by a short course of oral or intravenous steroid if there is serious new disability. High-dose steroids given late in pregnancy can cause neonatal adrenal suppression.

The manufacturers of interferon-β advise women taking it to avoid pregnancy and discontinue it during pregnancy and breastfeeding unless there are compelling reasons to continue with therapy.

Many women with multiple sclerosis have impaired bladder emptying, which predisposes to urinary tract infection. Severe spinal cord disease is a particular risk because it may mask the usual symptoms of urinary infection; regular urine culture is a sensible precaution. Paraplegia (from any cause) otherwise has little effect on pregnancy, but can lead to premature and unheralded labour, hence regular monitoring is needed in the third trimester. High spinal cord lesions can cause autonomic instability during labour; this can be blocked by careful regional anaesthesia.

Movement disorders
Pregnancy aggravates any tendency to chorea, an effect termed chorea gravidarum. This should not be regarded as a specific diagnosis, and unless there is a definite history of previous Sydenham's chorea it should prompt a search for all the usual causes of the condition, including thyrotoxicosis and systemic lupus erythematosus. Chorea can be florid and exhausting so that treatment with a small dose of a neuroleptic such as haloperidol may be required. Recurrence in subsequent pregnancies (or with the combined oral contraceptive) is common, perhaps because of the effects of oestrogens on the sensitivity of dopamine receptors.

Parkinsonism is rare in women of child-bearing age but tends to worsen slightly during pregnancy. Preconceptual counselling is difficult because there are no useful data in relation to the teratogenicity of the drugs used in young patients; levodopa has teratogenic effects in animals. Dystonic disorders also sometimes worsen in pregnancy, the effect being especially marked in dopa-responsive dystonia where an increase in levodopa therapy may be required. Wilson's disease is an exception and sometimes improves in pregnancy. Concerns about the potential teratogenic effects of therapy with penicillamine must be balanced against the risks of catastrophic neurological deterioration if therapy is abruptly withdrawn, although in the future treatments such as zinc may turn out to be a safe alternative.