Though no single test will perfectly distinguish between preeclampsia and SLE, there are several approaches that may help.
- Low complement and rising dsDNA titers are more commonly seen with active SLE than preeclampsia;
- Other signs of active SLE, such as inflamed joints and flaring SLE cutaneous reactions, may signify an SLE flare; and
- Though both present with proteinuria, the urine sediment is usually benign in preeclampsia, whereas SLE nephritis will often have an active sediment with red blood cells, white blood cells, and casts.
Neonatal Lupus
An estimated 10% of babies born to women with Ro(SSA) and/or La(SSB) antibodies have signs of neonatal lupus. The majority of these babies will have a photosensitive rash (similar in appearance to subacute cutaneous lupus) prior to six months of age. Fortunately, the rash does not leave a scar and will resolve as the Ro and La antibodies are cleared by the infant. Up to 2% of babies, however, will develop congenital heart block as a result of in utero exposure to the pathogenic antibodies. No cases of complete heart block have been reversed with therapy. However, there are case reports of fetuses with first- or second-degree heart block reversing after therapy with dexamethasone.3 Therefore, frequent screening between the 16th and 28th weeks of gestation with a fetal echocardiogram to measure the PR interval is recommended. Any increase in the PR interval should prompt therapy with dexamethasone 4 mg each day.
Antiphospholipid Syndrome
APS is associated with a high risk for pregnancy loss and may increase the risk for preeclampsia and placental insufficiency. For a woman with prior pregnancy losses due to APS, therapy with low–molecular weight heparin and aspirin during pregnancy may significantly improve her chances to deliver a live baby. For women with the antibodies of the syndrome (anticardiolipin or anti-b2-glycoprotein1 antibodies, or the lupus anticoagulant) but no prior pregnancy losses or thromboses, the best course of treatment is more difficult to discern. Though definitive data are lacking, I recommend treating these women with low-dose aspirin throughout pregnancy.
Summary
In the 21st century, the majority of pregnancies in women with SLE will be successful, resulting in a well baby and a healthy mother. Planning prior to conception – in particular, timing the pregnancy to coincide with a period of SLE quiescence and modifying medications – can increase the chances for a happy outcome. Careful monitoring by a rheumatologist for SLE activity and a high-risk obstetrician for pregnancy and fetal troubles will provide the best opportunity for success. New, targeted therapies for SLE appear to be on the horizon. Systematic evaluation of the safety and efficacy of these drugs in pregnancy may lead to further pregnancy success in young women with SLE.
