Pregnancy in women with ALS is rare and is generally considered a potentially dangerous event. We describe four ALS cases associated with pregnancy, together with a review of the literature. Three of the four women described developed ALS during pregnancy. In three cases a normal delivery was performed, with a healthy child. One patient, with severe respiratory failure, underwent an interruption of pregnancy. Seven other cases are reported in the literature, featuring a total of 11 pregnancies. The association between pregnancy and ALS is quite rare, and a pathogenic relationship cannot be excluded. The pregnancy and the delivery may be normal, but respiratory function should be carefully monitored. Generally, ALS does not have deleterious effects on fetal development. However, pregnancy in a woman with severe respiratory failure may precipitate the disease.