The effect of pregnancy on disease activity in systemic lupus erythematosus remains controversial. Studies on lupus flares in pregnancy are discussed, including prospective data on severity of flares and organ involvement from the Hopkins Lupus Pregnancy Center. The major fetal concerns of miscarriage (due to the antiphospholipid antibody syndrome), pre-term birth (largely due to pre-eclampsia or premature rupture of membranes) and neonatal lupus, are reviewed.