Q&A: My toddler was diagnosed with mono and I'm 29 weeks pregnant.

According to one of the most respected texts on infections in pediatrics, the risk of transmitting the agent causing mono (EBV, or Epstein-Barr Virus) to an unborn baby is quite low. This is largely due to the fact that most women have already had an exposure, even if they don't remember having mono, and carry protective antibodies in their blood.

In pregnant women who do develop mono, it is still rare to see an affected baby, though scattered reports do exist. There haven't been any specific defects that this virus would cause identified in babies.

All in all, the chances seem very good that you need not worry about getting or passing on mono during this pregnancy, though you should mention the situation to your gynecologist, who may want to check your blood for the presense of antibodies. Incidentally, are you sure it's really mono in your toddler? This disease is much less commonly seen in toddlers than in older children and adolescents.