The recombinant humanized monoclonal antibody eculizumab has been shown to be effective and well tolerated in patients with anti-acetylcholine receptor antibody-positive, treatment-refractory generalized myasthenia gravis (gMG). Myasthenia gravis (MG) often affects women of child-bearing potential. However, management can be challenging during pregnancy, and current treatment options are limited due to potential teratogenicity. Data are currently lacking on the use of eculizumab in pregnant women with gMG. This case report describes a successful pregnancy in a young woman with treatment-refractory gMG treated with eculizumab before, during, and after pregnancy. Eculizumab appeared to have a favorable benefit-risk profile in this setting, with no treatment-related adverse effects noted in either the patient or the neonate. The patient remains neurologically stable on eculizumab, which she has now been receiving for 5 years. This first report of the use of eculizumab during pregnancy in a patient with treatment-refractory gMG suggests a potential role for eculizumab in this setting, although further clinical experience is necessary to support its use during pregnancy in women with MG.