[Polymyositis, dermatomyositis and pregnancy: high-risk pregnancy. A further case report and review of the literature]. / Polymyosites, dermatomyosites et grossesse: grossesse à haut risque. Nouvelle observation et revue de la littérature.

The authors report a new case where polymyositis/dermatomyositis and pregnancy were associated. The polymyositis and dermatomyositis appeared in the last third of the pregnancy. A caesarean operation had to be performed for fetal distress after 37 weeks of amenorrhoea. An apparently dead small-for-dates baby was born. Progress, however, after resuscitation of the baby was good. At 20 months after delivery the polymyositis and dermatomyositis also were improved. Two and a half years later there was no recurrence. In the light of cases that have previously been reported in the literature, it has been established that on the one hand pregnancy may trigger off the condition and worsen the PM/DM and on the other hand the condition has a bad effect on the progress of the pregnancy. 50% of the babies are born dead or die in the week after delivery and 55% are born prematurely. We discuss the possibility that PM/DM is of viral origin. A confirmation of this is the presence of viral inclusion bodies on electron microscopy found in the muscle cells of the patients who have PM/DM. However, in the previous history of these patients an acute viral myositis in childhood is a troublesome factor. Pregnancy, because it involves alterations in the immune responses of the patients, may lead to a recrudescence of a "sleeping" virus and so be responsible for the appearance or aggravation of polymyositis and dermatomyositis.