The mono thing would be all right apparently:

</font><blockquote><div id="quote"><font class="small">Quote:</font>
The presence of a mono infection during pregnancy is not associated with miscarriages or birt]h defects, but it does warrant close medical attention to fever, decreased appetite, and potential dehydration.

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From: http://www.drspock.com/article/0,1510,6072,00.html

Don't know about third tonsils; maybe the baby will be born with one :-)