You can not and I heard that was dangerous to get during pregnancy. My sister worked at a day care and could not work when they had an outbreak of that.
I found this and I don't know if it helps...but it seems like if she DID catch it, then as long as she was monitored by her OB the chance for complication or problems is very small::
http: // www . pregnancy-info . net/risk_factors_fifth_disease . html
obviously no spaces, LOL but MH likes to block out websites sometimes :)