LUPUS: A Guide for Nurses
In patients with SLE in remission, pregnancy does not confer a special risk to either the mother or the fetus, and routinely advising against pregnancy in SLE has been abandoned.
Fertility is usually normal in SLE patients. However, disease activity, end-stage renal disease and some of the drugs (i.e. cyclophosphamide) used in SLE can contribute to menstrual disorders. Risk of deep venous thrombosis in SLE patients using oral contraceptives is slightly increased compared to the general population and this risk increases further in those with antiphospholipid antibodies (anticardiolipin antibodies and/or lupus anticoagulant). It is our current practice to advise against oestrogen-containing oral contraceptive pills in women with positive antiphospholipid antibodies, although progesterone-only pills are safe.
The frequency of flares in pregnant SLE patients is slightly higher than the frequency in non-pregnant patients. These flares appear during the second and third trimesters of pregnancy and most commonly shortly after delivery of the baby. In general, flares are mild, mainly with joint and skin symptoms. However, between 10-20% may have severe flares with major organ involvement. In women with pre-existing stable lupus nephritis, pregnancy does not jeopardise renal function in the long term, although SLE nephropathy may manifest for the first time in pregnancy. Flares may be difficult to diagnose during pregnancy since many features such as hair-loss, oedema, facial erythema, fatigue, anaemia, raised ESR and musculoskeletal pain also occur in normal pregnancy.
The differentiation between renal flares and pre-eclampsia is critical. Both entities share clinical features such as oedema, hypertension and proteinuria. The presence of other features of SLE, the reduction in C3 and C4 complement factors and the presence of cellular casts in the urinary sediment favour the diagnosis of a lupus flare.
Active lupus is associated with an increase in pre-term deliveries and small-for-gestational-age babies. Renal disease may predispose to pre-eclampsia and intra-uterine growth retardation and, if active, lead to more frequent fetal losses. These maternal and fetal factors support the need for treatment of flares.
Fifteen years ago, Hughes first described a clinical syndrome associated with the presence of circulating antibodies against phospholipids (see 'Antiphospholipid (Hughes) Syndrome'). One of the major features of the syndrome in women is pregnancy loss, most typically in the second trimester. The mechanism which leads to fetal loss is unknown. The most probable culprit is placental vessel thrombosis and treatment aimed at anticoagulation has significantly improved pregnancy outcome in these patients. It is now known that the most important risk factor for pregnancy loss in lupus patients is the presence of antiphospholipid antibodies.
Patients and non-specialist doctors are sometimes surprised to learn that many of the drugs normally used in lupus are considered safe in pregnancy. These include prednisolone, azathioprine, hydroxychloroquine, NSAIDs (e.g.Naproxen) and low-dose aspirin. For women with anticardiolipin antibodies or lupus anticoagulant, we sometimes also use self-injected low-dose heparin, which does not cross the placenta.
Pregnancy care is best undertaken in combined clinics where physicians and obstetricians can regularly monitor lupus disease activity, as well as fetal growth parameters, uterine artery Doppler blood-flow examination at 20-24 weeks, and umbilical artery blood flow from 24 weeks. These tests, in skilled hands, can guide the obstetrician in deciding when the baby ought to be delivered.
This illness of the fetus and neonate is considered a model of passively acquired autoimmunity, in which antibodies (anti-Ro) produced by the mother, in crossing the placenta, are thought to have the potential to cause skin rashes and to injure fetal heart conduction tissue. Neonatal lupus was so termed because the cutaneous lesions of the neonate resembled those seen in SLE. These skin lesions usually appear 2-3 weeks after birth and resolve without treatment after approximately 6 months. In very rare cases these babies can have problems with the conducting system which controls the heart beat. This condition is known as congenital heart block and is usually irreversible. Most babies with this condition require a pacemaker. It should be emphasised that, although anti-Ro antibodies occur in about 25% of all lupus patients, the risk of congenital heart block is small (less than 2%).
Breastfeeding is rarely contra-indicated in lupus patients, although those patients on 30 mg prednisolone with healthy term babies may consider bottle feeding because of the theoretical risk of fetal hypothalmic-pituitary-adrenal axis suppression at high doses. None of the cytotoxic medication, frequently used to treat severe lupus (cyclophosphamide, azathioprine or methotrexate), is safe during lactation. Heparin and oral anticoagulants (used frequently to treat patients with thrombosis associated with antiphospholipid antibodies) are safe drugs for the nursing mother.