The physiological adaptation of the immune system to pregnancy can potentially affect the course of all autoimmune rheumatic diseases (ARD), conversely the autoimmune processes characteristic of these conditions may compromise the foetal outcome. Unfortunately, very few reports on pregnancy outcome in patients with rare ARD are available. In this paper, we briefly review the data published until now on these disorders. Some general guidelines which were elaborated for more prevalent ARD seem to be valid also for such rare conditions: 1) patients should be correctly informed on the risk of becoming pregnant; 2) pregnancies should be planned when the disease is in remission since it increases the probability of successful maternal and foetal outcome; 3) patients should be regularly monitored during gestation and postpartum by a multidisciplinary team including rheumatologist, obstetrician, and neonatologist; 4) in the case of disease relapse an adequate treatment, even aggressive if necessary, should be recommended since active disease can be more detrimental for foetus than drugs; 5) pregnancies complicated by the onset of rare ARD have a particularly severe prognosis; in these cases a prompt treatment and very close clinical surveillance are indicated.