Lupus activity during pregnancy has been the subject of much research and debate recently. Data point to increased SLE activity during pregnancy. SLE may flare during any trimester of pregnancy, as well as in the puerperium; however, flares are usually mild, affecting skin and joints, and, unless affecting the kidney, do not confer any adverse prognosis on pregnancy outcome. Diagnosis of SLE flares can be difficult during pregnancy and must rely on a thorough clinical and laboratory assessment. Recent data link sex hormones, particularly prolactin, to SLE activity, which may be one explanation for the high frequency of SLE flares during pregnancy. No data support the thesis that corticosteroids prevent SLE flares during pregnancy, and therefore, prophylactic prednisone should not be given routinely. HCQ does seem to be safe for the fetus, however. SLE flares can be treated, depending on severity, with NSAIDs or with HCQ, prednisone, or azathioprine.