Neonatal Lupus

Michael D. Lockshin, M.D.

Special Assistant to the Director, Clinical Center, NIH, Bethesda, Maryland

When lupus complicates pregnancy, one of the things that frightens prospective and new parents most is the throught that their child might have the mother=s disease. Parents who have heard of a condition (wrongly) called "neonatal lupus" often imagine that terrifying things might happen to their child. Most of the time they need not worry. The facts, as we understand them, are as follows:

 Neonatal lupus is very different from systemic lupus erythematosus;

it does not develop into SLE.

 Neonatal lupus is rare.

 In most cases, neonatal lupus is not serious and does not need to be treated.

 In most cases, neonatal lupus disappears spontaneously in a few weeks, leaving

no after-effects.

 With a blood test, it is possible to tell which women will not deliver a child who

develops neonatal lupus.

 Many children with neonatal lupus are born to mothers who do not have SLE.

What is neonatal lupus?

The term is used to describe three major symptoms found in newborns. The commonest symptom is a rash. It can take many forms, but is usually scattered over the body, not necessarily on the face. It shows up a few days or weeks after birth, particularly after sun exposure, and usually disappears after a few more weeks, leaving no scar. The rash looks like many other rashes that babies get. It can be identified definitively only by biopsy, but just doing a blood test and waiting for the rash to disappear is all that is needed.

The second commonest sysmtom is an abnormal blood count: low platelets, anemia, and other abnormalities. Again, this is seldom serious; these abnormalities usually go away in a few weeks with no treatment.

The rarest abnormality, but a serious one, is a heart rhythm abnormality know as congenital heart block. A normal heartbeat starts in the upper heart (the atria or auricles) and travels smoothly through to the bottom of the heart (the ventricles). In heart block, the atrial beat (about 140 times per minute in a newborn) cannot get through to the ventricles because scar tissue blocks its path. The ventricles then have beat on their own (about 60 times per minute in a newborn).

Since the vertricle beat determines the pulse, the baby has an abnormally slow pulse.

Congenital heart block can often be diagnosed between the 15th and 25th week (4th to 6th month) of pregnancy. If the unborn baby has heart block but appears to be doing well, either nothing is done, or a special form of cortisone is given that will go through the placenta to the baby, but it may not make the heart beat normally again. If the baby is not doing well and is big enough to deliver (30 weeks into pregnany or later), delivery is often the best way of handling the problem. After birth, many babies with congenital heart block lead normal lives with no treatment, but some need pacemakers, and a small number die from heart disease.

Neaonatal lupus is not the same as adult lupus. Babies with neonatal lupus do not develop arthritis, fever, kidney or brain disease.

How can risk be predicted?

One of the statling recent findings about neonatal lupus is that essentially all mothers of infants with neonatal lupus have a specific set of antibodies. The antibodies are those called anti-Ro (also called anti-SSA) and anti-La (also called anti-SSB). Only about one-third of all lupus patients have these antibodies. For practical purposes, the mother who has neither anti-Ro nor anti-La antibodies (about two-thrids of all lupus patients) has no chance of delivering a child with any manifestation of neonatal lupus. The mother who has anti-Ro but not anti-La antibodies has about a 25% risk of delivering a child who will develop rash or blood abnormalities. Those women who have both anti-Ro and anti-La antibodies are at highest risk for delivering a child with congenital heart block, but even so, most women with both kinds of antibodies have normal children. (It is very rare for a woman to have only anti-La and not anti-Ro.)

If a woman has already had one child with neonatal lupus, the risk that her next child will develop the illness is only about 25%.

Many woman who deliver children with neonatal lupus do not have symptoms of lupus. In fact, except for their abnormal blood tests, many are well. Looking at the question the other way, no specific characteristics (except the antibodies) of the illness of the mother already diagnosed with lupus changes the risk of neonatal lupus. Lupus patients who are sick are no more nor less likely to have a child with neonatal lupus than lupus patients who are well.

What happens to the affected child?

It would be nice to give a definitive answer to this question, but because the anti-Ro and anti-La antibody tests have been widely available for only a short time, and because the diagnosis of neonatal lupus has been easily made for only ablout a decade, most of the children now known to have had neonatal lupus have not yet grown up. As children and adolescents they seem normal. Doctors who have studied them feel that they have no higher risk of developing SLE than does any other close relative of the SLE patient. Those with heart disease need to see cardiologists because many will eventually need pacemakers or other treatment.

Are there any special ways to manage a lupus pregnancy to prevent neonatal lupus?

To date there is no know way to prevent neonatal lupus, but risk can be defined. All pregnant lupus patients can be tested for anti-Ro and anti-La antibodies. Woman who test negative can be reassured they will not have a child with neonatal lupus. Those who test positive for only the anti-Ro antibody should be alerted about the possibility of rash and blood test abnormalities in the child, but should not worry unduly. In most cases, warning the pediatrician not to panic is sufficient. (Pediatricians are often unfamiliar with neonatal lupus.) For pregnant woman who have both anto-Ro and anti-La antibodies, periodic checks on the baby=s heartbeat (fetal echocardiography), especially between weeks 15 and 25 of pregnancy , will identify unequivocally whether or not the baby=s heart is normal. If the heartbeat is normal, there is no further worry once the baby is born. If any abnormality does occur, the best available obstetric/perinatology/cardiology opinions should be obtained, since treatment of this condition requires special skill.

From Lupus Letter Volume 1, No. 1