Systemic lupus erythematosus (SLE) is a chronic inflammatory multisystem disease. Most women with SLE have normal fertility, but they are at higher risk of pregnancy complications including hypertension, preterm labour, thrombosis and postpartum haemorrhage. There is a higher incidence of miscarriage and fetal loss especially in women with co-existing antiphospholipid syndrome (presence of lupus anticoagulant and anticardiolipin antibodies).
Neonatal lupus — Neonatal lupus is a passively acquired autoimmune disease that occurs in about 2 percent of babies born to mothers with anti-Ro/SSA and/or anti-La/SSB antibodies. It is caused by passage across the placenta after about the 20th week of pregnancy of anti-Ro/SSA and/or anti-La/SSB antibodies to intracellular ribonucleoproteins. Antibody levels are reported by the lab in GG&C. Approximately 50% of women who give birth to a baby with the neonatal lupus syndrome do not have a diagnosis of lupus or any other autoimmune disease (eg Sjögren’s syndrome) at the time of their pregnancy despite the presence of anti-Ro/SSA or anti-La/SSB antibodies. Around half of these mothers will go on to develop autoimmune disease, and they should all therefore be referred to a rheumatologist for assessment postnatally.
Signs of neonatal lupus include a red, raised rash on the scalp and around the eyes. The rash almost always resolves by six to eight months of age following clearance of the maternal antibodies and the majority (90 percent) of these infants do not subsequently develop lupus.
Infants may also demonstrate transient abnormalities of liver function and generalised or selective reduction in cellular blood components, e.g., anaemia, reduced white cell count and/or thrombocytopenia.
The most common cardiac manifestation of neonatal lupus is complete heart block, which occurs in approximately 2 percent of newborns whose mothers have anti-Ro/SSA or anti-La/SSB antibodies. Complete heart block may rarely be associated with cardiomyopathy secondary to endocardial fibroelastosis (EFE), and is irreversible.
Women with known anti-Ro/SSA or anti-La/SSB antibodies will undergo weekly monitoring of the fetal heart rate using Doptone, starting from 18 weeks of pregnancy. Four weekly ultrasound scans will be undertaken from 20 weeks of gestation onwards, aiming to detect fetal heart block at an early stage to allow monitoring of fetal cardiac function and alert the neonatal/cardiology team to the potential need for a pacemaker after birth.
There is at present no proven treatment for fetal heart block prior to birth. There have been reported cases of reduction in the degree of heart block and reversion to sinus rhythm after maternal steroid therapy but dexamethasone is not recommended as prophylaxis to prevent fetal congenital heart block (1). Neither has intravenous immunoglobulin been established as an effective preventative treatment (2). A ventricular heart rate of <55 beats per minute, reduced left ventricular function, hydrops, presentation earlier in pregnancy and reduced cardiac function are risk factors for fetal and neonatal death. Antenatal treatment with an alpha-sympathomimetic drug is not routinely employed due to the risks to the maternal health (3,4).
If a mother gives birth to a baby with neonatal lupus, her risk of having a child with neonatal lupus in a subsequent pregnancy is 16-18%. Several maternal therapies have been trialled in a bid to prevent CHB in a further pregnancy, however evidence is lacking.