These are extracts from the consensus recommendations of our working group. Their purpose is to provide a reference source for patients and their doctors, nurses and midwives before, during and after pregnancy. The points have been divided into stages to aid clarity. These guidelines apply particularly to those with myasthenia gravis (MG) but the principles are applicable to those with congenital myasthenic syndromes (CMS) and Lambert-Eaton myasthenic syndrome (LEMS). The main messages for women with myasthenia are:

  1. To try to plan beforehand by optimising your myasthenic control beforehand;
  2. If you are unexpectedly pregnant, not to make any sudden medication changes without discussing with your medical team;
  3. The ideal is for your care to be undertaken by a multidisciplinary team during pregnancy, delivery and after birth;
  4. Be assured that the majority of women with well-controlled myasthenia are able to have a normal pregnancy and delivery;
  5. Newborn babies born to mothers with myasthenia are at risk of transient myasthenic weakness, even if the mother's myasthenia is well-controlled, and those babies need close observation in the first few days after birth.

Pre-pregnancy

The issue of possible pregnancy should be raised with all female teenagers and adults with myasthenia, even if there are no plans to become pregnant for may years to come. This allows options, especially drug choices, to be considered in advance. For those who have definite plans to become pregnant soon, every woman should be seen by her neurologist before pregnancy and be given advice regarding optimal management of her myasthenia. Specific advice about the safety of different drugs in pregnancy should be discussed, and safe immunosuppressive agents or pyridostigmine should not be altered. For those already on drugs that may harm the unborn child, such as methotrexate or mycophenolate mofetil (MMF), the need for early planning is even more important. The relative risks and potential management options need careful discussion with the specialist. It may be appropriate to use effective contraception whilst considering the options. If appropriate, thymectomy should be performed well before planned pregnancy.

Pregnancy

Women who have not received pre-pregnancy counselling should be offered the above advice in early pregnancy and reassured concerning the safety of prednisolone, azathioprine, ciclosporin and pyridostigmine in pregnancy and advised not to stop these drugs without advice. Those who have unplanned pregnancies conceived whilst receiving methotrexate or MMF should be counselled about the possible adverse effects. However, abrupt withdrawal of these drugs once pregnancy is confirmed may be too late to avoid adverse effects on the unborn baby. It also risks deterioration in disease control so may not be appropriate.

Women with myasthenia should be managed during pregnancy by colleagues from different specialities working together, ideally a neurologist, specialist nurse / midwives, obstetrician with an interest in maternal medicine, and an obstetric anaesthetist. A care plan, including how to access direct advice from their neurological team, who should have expertise in the management of myasthenia in pregnancy, should be drawn up and documented.

Women with stable myasthenia in pregnancy can be reassured that, with current management, most will not experience deterioration in their myasthenia, and the myasthenia is unlikely to affect the timing or type of delivery.

Women with myasthenia should have thyroid function tests performed early in pregnancy if they have not been performed within the year, prior to pregnancy.

Certain infections, particularly urinary tract infections, are more common in pregnancy. These should be looked for and treated promptly with antibiotics appropriate for use in myasthenia and in pregnancy.

Guidance concerning drugs to be used with caution in women with myasthenia should be incorporated into the hand-held pregnancy notes. Specific advice should be sought from the pharmacy and the neurological team if a particular drug on the list is required.

A foetal scan at 12 and 20 weeks' gestation should be offered. Maternal monitoring of foetal movements, particularly after 24 weeks' gestation, should be encouraged. If there are any concerns, additional foetal scans should be arranged in a specialist unit. This is to exclude excess amniotic fluid build-up, to assess foetal movements and to look for any joint problems.

Delivery

There should be multidisciplinary team involvement in labour with input from an obstetrician, anaesthetist, neonatologist and a neurologist. On-site intensive care facilities should be available, particularly for women with more severe disease.

In women with well-controlled myasthenia vaginal delivery with spontaneous onset of labour should be the aim. Caesarean section should be performed only for obstetric indications. Women should continue their usual medications including pyridostigmine during labour. Women on long-term oral steroids should be given additional intravenous steroids in labour. Many of the anaesthetic drugs deemed as contrainidicated can be used safely in myasthenia with appropriate monitoring. Even so, epidural is preferable to general anaesthesia whenever possible. Magnesium sulphate should be avoided unless there is severe eclampsia, and then only with extreme caution.

Healthcare professionals and women with myasthenia should be aware that transient neonatal myasthenia gravis (TNMG) is a recognised complication of maternal myasthenia gravis, reagrdless of the severity of the mother's disease. TNMG causes a "floppy baby" with muscle weakness and difficulty with crying, swallowing and breathing. Therefore delivery should occur in a unit with immediate neonatal / paediatric expertise. Delivery in midwifery-led units or home delivery is not appropriate.

After the Birth

Mother

Breastfeeding should be encouraged and is not contraindicated with maternal prednisolone, azathioprine or pyridostigmine treatment. Women should seek early review by their neurological team after delivery, and particularly if they experience any deterioration in their symptoms following surgery or infection, and ideally should be reviewed routinely in clinic within a few weeks.

Baby

We recommend a period of postnatal observation for all infants of affected mothers, focusing on signs and symptoms indicative of transient neonatal myasthenia gravis (TNMG). As onset of TNMG may be delayed for hours up to several days, at present we recommend an inpatient observation period of at least two days. Treatment of TNMG is mainly supportive through managing feeding difficulties and providing adequate respiratory support. Pyridostigmine may be needed for some babies. More severe cases should be managed in a neonatal unit.

 

Myasthenia in pregnancy: Best practice guidelines from a UK multispecialty working group.

Norwood F, Dhanjal M, Hill M, James N, Jungbluth H, Kyle P, O'Sullivan G, Palace J, Robb S, Williamson C, Hilton-Jones D, Nelson-Piercy C. J Neurol Neurosurg Psychiatry. 2014 May;85(5):538-43. doi: 10.1136/jnnp-2013-305572. Epub 2013 Jun 11).

This article was adapted by kind permission of the publishers