Multiple sclerosis is a disease of unknown aetiology in which the clinical symptoms are caused by patches of damage to the myelin sheath of the central, but not peripheral, neurones. The onset of the disease is generally between the ages of 20 and 40 years and it is usually a disease of relapse and remission. The prevalence of the disease is around 110 per 100,000 in the UK, and it is more common in females (two out of three patients will be female). Therefore, it is not uncommon in women who present for obstetric care.
The condition may manifest with varying degrees of sensory abnormalities, visual disturbance, motor weakness, cranial nerve or bladder and/or bowel dysfunction. Cognitive impairment or epilepsy may be present in some patients. The rate of relapse may decrease during pregnancy, especially in the third trimester, and pregnancy is usually well tolerated, although the rate of relapse may increase in the first three months postpartum before returning to the basal rate
Problems and special considerations
Anaesthetists might feel reluctant to perform regional analgesia in these women, since a relapse may occur after a stressful event such as delivery of a baby. The regional anaesthetic may then erroneously be blamed. Previous studies have suggested an increased incidence of relapse if higher concentrations of bupivacaine are used, although subsequent evidence has not confirmed this.
Women who are very disabled may have impairment of laryngeal reflexes and ventilation. Those with kyphosis, scoliosis or muscle spasticity may be unable to position themselves for regional blockade, and some may be physically unable to achieve a vaginal delivery without assistance.
Women will be concerned about any possible effect of regional analgesia and anaesthesia on their disease.
Management options
Antenatal counselling is advised if possible, to enable a plan for analgesia and anaesthesia to be drawn up and documented in the mother’s notes. Time should be taken to discuss the risks and benefits of regional techniques so that the woman may give informed consent where appropriate. It is good practice to assess and document any pre-existing neurological deficit before performing a regional block.
There is no logical reason why these women should not have regional analgesia, and there may be benefits in reducing the stress of labour caused by pain while maintaining as much motor power as possible. Similarly, both spinal and epidural anaesthesia are suitable if operative delivery is necessary. If general anaesthesia is required, standard techniques are used. Suxamethonium may cause exaggerated hyperkalaemia in patients with severe progressive debilitating disease and should be avoided. Measures to minimise the risk of infection must be observed and maternal temperature must be monitored, as a small rise may exacerbate existing symptoms or trigger a relapse.
Key points
• Epidural analgesia should not be denied to women with multiple sclerosis.
• Relapse is not more common with regional anaesthesia than without.
• Routine techniques are used, taking into account any pre-existing neurological deficit.
Further reading
Hopkins AN, Alshaeri T, Akst SA, Berger JS. Neurologic disease with pregnancy and considerations for the obstetric anesthesiologist. Semin Perinatol 2014; 38: 359-69.
Tsui A, Lee MA. Multiple sclerosis and pregnancy. Curr Opin Obstet Gynecol 2011; 23: 435-9.