Babies born to mothers with autoimmune problems and SSA antibodies are at risk for congenital complete heart block (slow heart rate).

Why is my baby at risk for a slow heart rate?

When SSA antibodies pass from the mother to the baby in the womb they can inflame the baby’s heart muscle.

  • This is most common between 18 and 24 weeks, but can happen at any point during pregnancy
  • Only 3 to 5% of babies born to mothers with these antibodies develop a slow heart rate
  • It is not known why some babies do develop a slow heart rate and others do not

What can SSAs do to my baby's heart?

SSAs can lead to:

  • Leaky heart valves
  • Poor heart function, or
  • Slow heart rate

The risk of having a baby with a slow heart rate due to SSA antibodies is higher if the mother has any of the following:

  • Low thyroid
  • SSB antibodies
  • A prior child with slow heart rate (15-20% likely to happen again with future children)
  • High level of SSA antibodies (>100U/ml)

Some studies show that the use of a drug called Plaquenil may protect the baby’s heart while in the mother. The reason for this is unknown.

Mothers with SSA antibodies should have the baby’s heart checked while pregnant. A test called an echocardiogram is taken when the mother is 18,20,22,24, and 32 weeks along in her pregnancy. This test is not harmful to the baby.