Systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease able to cause inflammatory damage to many different organ systems. Women are affected more often than men (10 to 1) and frequently during their reproductive years (1 in 700 women). Since fertility is generally preserved, SLE is not uncommonly encountered during pregnancy (1 in 1600 pregnancies). The diagnosis of SLE can be made with certainty when four or more of the criteria listed in Box 28.1 are fulfilled. A positive antinuclear antibody (ANA) alone, especially in low titers, does not identify patients at increased risk of pregnancy complications unless found in a suspicious clinical context. Nevertheless, even when the strict criteria for SLE are not met, women with the so-called lupus-like disease (LLD) may experience pregnancy complications.

Timing of pregnancy and disease activity

For patients seeking preconception or early pregnancy counseling, the prognosis is related to the following factors:

• current disease activity
  
• end organ damage (especially renal impairment)
  
• medications required to maintain remission
  
• presence or absence of the antiphospholipid antibody syndrome (APS)
  
• presence of autoantibodies associated with fetal damage such as anti-Ro/SS-A and anti-La/SS-B.

Knowledge of disease activity prior to pregnancy is important in estimating the risk of a SLE exacerbation and superimposed pre-eclampsia. Patients in remission for 6–12 months before pregnancy have a 35% risk of exacerbation or superimposed pre-eclampsia during pregnancy and a better than 90% chance of having a viable pregnancy while the risk for patients not in remission prior to pregnancy is approximately 60% for exacerbation or superimposed pre-eclampsia and 50% for a viable pregnancy outcome. Therefore, the optimal time to plan a pregnancy should be when the SLE has been in remission for at least 6–12 months.

Lupus exacerbations have been said to occur unpredictably and at any time during pregnancy or post partum but more recent case-controlled studies have found fewer exacerbations in the third trimester. This finding has been related to lower levels of cytokines (particularly IL-6), estradiol and progesterone in SLE women than in non-SLE, normal pregnant controls. These lower levels have been attributed to a reduced placental production of these compounds and it is suggestive of placental damage in women with SLE. Other recent studies have also shown that postpartum exacerbations were not more frequent in women with SLE than in nonpregnant SLE control patients followed for a similar length of time.

Patients with active renal disease (lupus nephritis) have a poorer prognosis. Between 40% and 60% develop superimposed pre-eclampsia, which may be difficult to distinguish from an SLE exacerbation. Besides clinical symptoms, active urinary sediments, high anti-DNA antibody titers and low serum complement levels will support the diagnosis of lupus exacerbation but still it might be very difficult to differentiate superimposed pre-eclampsia from a lupus flare. Until recently, if a lupus exacerbation was felt to be present, the patient’s response to specific therapy for lupus and continued observation was used to determine if a lupus flare or superimposed pre-eclampsia was the main cause of the deterioration. Lately, the Lupus Activity Index to define a lupus flare in nonpregnant patients has been validated and adapted for use in pregnancy as well. Three activity scales, specific for pregnancy, will help to better identify a lupus flare since they showed a 93% sensitivity and 98% specificity: the SLE Pregnancy Disease Activity Index (SLEPDAI), the Lupus Activity Index in Pregnancy (LAI-P), and the modified Systemic Lupus Activity Measure (m-SLAM).

Management of medications

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