eMedicine Specialties > Obstetrics and Gynecology > Medical Problems in Pregnancy

Myasthenia Gravis and Pregnancy

Author: Idan Sharon, MD, Consulting Staff, Departments of Neurology and Psychiatry, Cornell New York Methodist Hospital; Private Practice
Contributor Information and Disclosures

Updated: Dec 13, 2007

Introduction

Background

Myasthenia gravis (MG) is an autoimmune neuromuscular disease characterized by weakness and fatigue of the skeletal muscles of the face and extremities. It affects people of both sexes and all ages, but twice as many female patients are affected as male patients. MG usually strikes in women in their third decade of life.

Pathophysiology

The underlying pathology is the production of autoantibodies against human acetylcholine receptors (AChRs), usually immunoglobulin G, which can be detected in as many as 90% of patients. These antibodies interfere with the conduction of impulses across myoneural junctions by decreasing the number of available AChRs at neuromuscular junctions. Patients with milder symptoms tend to have lower antibody titers. Patients with thymoma and more severe disease have higher titers. Some MG patients may not have detectable antibody levels.

MG typically affects females during their reproductive years. Difficulties specific to pregnant patients can be concerning, and the course of MG during pregnancy is hard to predict. Patients may have disease exacerbation, crisis, or, interestingly enough, remission. Although the disease course is variable, pregnant patients face risks of exacerbation, respiratory failure, adverse drug response, crisis, and death.

Mitchell and Bebbington reviewed the performance of MG patients during pregnancy at the Vancouver Salvation Army Grace Hospital. Four of 9 patients experienced antepartum exacerbations ranging from muscle weakness to respiratory failure. Three of the 4 patients had undergone previous thymectomy, and the patient with the worst symptoms (respiratory failure) had a prior thymectomy.1 These findings negate studies that concluded that thymectomy leads to fewer exacerbations.

In a large study from 1991, Plauche found that exacerbations occurred in approximately 41% of patients during pregnancy and in 29.8% of patients postpartum. Approximately 4% of patients died because of worsening of the disease or because of treatment complications.2

A study by Batocchi et al reported that the disease worsened in 10 (19%) of 54 patients. Approximately 60% of exacerbations occurred during the first trimester, and approximately 28% of patients deteriorated immediately after delivery. Premature delivery occurred in 4 (7.4%) of 54 patients. Cesarean delivery was performed in 16 pregnancies (30%). The study concluded that no correlation exists between MG severity before and during pregnancy.3

Frequency

International

Worldwide prevalence is approximately 40 cases per million population, and the incidence is 1 case in 20,000-40,000 population per year.

Race

Persons of all races are affected.

Sex

Both sexes are affected, and the female-to-male ratio is 2:1.

Age

Persons of any age are affected, but MG usually affects women in their third decade of life.

Clinical

History

Patients with myasthenia gravis present with symptoms such as ptosis, diplopia, breathing and swallowing difficulties, and weak limbs. Intermittent ptosis and diplopia are usually the initial reported symptoms. Symptoms usually become generalized within 1 year. Symptoms fluctuate in severity; they worsen with exertion and are relieved with rest. Fatigue upon exertion is essential to making the diagnosis. Despite these common presenting symptoms, some patients have atypical presentations.

Physical

Upon physical examination, muscle strength should be assessed by having the patient squeeze the examiner's hand repeatedly or having the patient flex her arm against resistance. Facial weakness can be evaluated by asking the patient to smile. A snarling expression may be evident when the patient attempts to smile. Although muscles are weak, deep tendon reflexes are preserved. Diplopia and ptosis should also be addressed.

Causes

The underlying pathology is the production of autoantibodies against human AChRs, usually immunoglobulin G, which can be detected in as many as 90% of patients.

More on Myasthenia Gravis and Pregnancy

Overview: Myasthenia Gravis and Pregnancy
Differential Diagnoses & Workup: Myasthenia Gravis and Pregnancy
Treatment & Medication: Myasthenia Gravis and Pregnancy
Follow-up: Myasthenia Gravis and Pregnancy
References
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References

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  2. Plauche WC. Myasthenia gravis in mothers and their newborns. Clin Obstet Gynecol. Mar 1991;34(1):82-99. [Medline].

  3. Batocchi AP, Majolini L, Evoli A, et al. Course and treatment of myasthenia gravis during pregnancy. Neurology. Feb 1999;52(3):447-52. [Medline].

  4. Rolbin WH, Levinson G, Shnider SM, Wright RG. Anesthetic considerations for myasthenia gravis and pregnancy. Anesth Analg. Jul-Aug 1978;57(4):441-7. [Medline].

  5. Ip MS, So SY, Lam WK, et al. Thymectomy in myasthenia gravis during pregnancy. Postgrad Med J. Jun 1986;62(728):473-4. [Medline].

  6. Batashki I, Markova D, Milchev N, Terzhumanov R, Uchikova E, Uchikov A. [Myasthenia gravis and pregnancy--a case report and review of the literature]. Akush Ginekol (Sofiia). 2006;45(7):59-61. [Medline].

  7. Brenner T, Beyth Y, Abramsky O. Inhibitory effect of alpha-fetoprotein on the binding of myasthenia gravis antibody to acetylcholine receptor. Proc Natl Acad Sci U S A. Jun 1980;77(6):3635-9. [Medline].

  8. Carr SR, Gilchrist JM, Abuelo DN, Clark D. Treatment of antenatal myasthenia gravis. Obstet Gynecol. Sep 1991;78(3 Pt 2):485-9. [Medline].

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  19. McNall PG, Jafarnia MR. Management of myasthenia gravis in the obstetrical patient. Am J Obstet Gynecol. Jun 15 1965;92:518-25. [Medline].

  20. Newsom-Davis J, Willcox N, Schluep M, et al. Immunological heterogeneity and cellular mechanisms in myasthenia gravis. Ann N Y Acad Sci. 1987;505:12-26. [Medline].

  21. Ramirez C, de Seze J, Delrieu O, et al. [Myasthenia gravis and pregnancy: clinical course and management of delivery and the postpartum phase]. Rev Neurol (Paris). Mar 2006;162(3):330-8. [Medline].

  22. Sax TW, Rosenbaum RB. Neuromuscular disorders in pregnancy. Muscle Nerve. Nov 2006;34(5):559-71. [Medline].

  23. Shehata HA, Okosun H. Neurological disorders in pregnancy. Curr Opin Obstet Gynecol. Apr 2004;16(2):117-22. [Medline].

  24. Téllez Zenteno JF. Can we consider thymectomy before pregnancy in female patients with myasthenia gravis?. Eur J Cardiothorac Surg. Aug 2006;30(2):411-2; author reply 412. [Medline].

  25. Vincent A, Newsom-Davis J. Acetylcholine receptor antibody as a diagnostic test for myasthenia gravis: results in 153 validated cases and 2967 diagnostic assays. J Neurol Neurosurg Psychiatry. Dec 1985;48(12):1246-52. [Medline].

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Further Reading

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Keywords

MG, autoimmune neuromuscular disease, human acetylcholine receptors, AChRs, pregnancy complications, pregnancy comorbidity, autoimmune neuromuscular disease, rheumatoid arthritis, systemic lupus erythematosus, SLE, pemphigus, Hashimoto thyroiditis, Hashimoto's thyroiditis, thymic abnormality, scleroderma, dermatitis herpetiformis, autoimmune hemolytic anemia, polymyositis, sarcoidosis, MG and pregnancy

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Contributor Information and Disclosures

Author

Idan Sharon, MD, Consulting Staff, Departments of Neurology and Psychiatry, Cornell New York Methodist Hospital; Private Practice
Idan Sharon, MD is a member of the following medical societies: American Academy of Neurology, American Medical Association, and Medical Society of the State of New York
Disclosure: Nothing to disclose.

Medical Editor

Bryan D Cowan, MD, Professor and Chairman, Department of Obstetrics and Gynecology, University of Mississippi College of Medicine; Consulting Staff, Department of Obstetrics and Gynecology, Veterans Affairs Medical Center; Medical Director, Wiser Hospital for Women, University of Mississippi Medical Center
Bryan D Cowan, MD is a member of the following medical societies: American Association of Gynecologic Laparoscopists, American College of Obstetricians and Gynecologists, American Gynecological and Obstetrical Society, American Medical Association, American Society for Reproductive Medicine, Association of Professors of Gynecology and Obstetrics, Central Association of Obstetricians and Gynecologists, Endocrine Society, Sigma Xi, Society for Assisted Reproductive Technologies, Society for Gynecologic Investigation, Society for the Study of Reproduction, and Society of Laparoendoscopic Surgeons
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Gail F Whitman-Elia, MD, Professor, Department of Obstetrics and Gynecology, University of South Carolina School of Medicine
Gail F Whitman-Elia, MD is a member of the following medical societies: American Association of Clinical Endocrinologists, American College of Clinical Endocrinologists, American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine, American Medical Association, American Medical Women's Association, American Public Health Association, American Society for Reproductive Medicine, Endocrine Society, and South Carolina Medical Association
Disclosure: Nothing to disclose.

CME Editor

Frederick B Gaupp, MD, Consulting Staff, Department of Family Practice, Assumption Community Hospital
Frederick B Gaupp, MD is a member of the following medical societies: American Academy of Family Physicians
Disclosure: Nothing to disclose.

Chief Editor

David Chelmow, MD, Professor of Obstetrics and Gynecology, Tufts University School of Medicine; Program Director, Tufts University Affiliated Hospitals OB/GYN Residency Program; Chair, Tufts University Health Sciences Campus Institutional Review Board
David Chelmow, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Medical Association, Association of Professors of Gynecology and Obstetrics, Massachusetts Medical Society, Phi Beta Kappa, Sigma Xi, Society for Gynecologic Investigation, and Society for Medical Decision Making
Disclosure: Nothing to disclose.

 
 
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