Use conditional fields for the fields that may be blank added to the
previous line eg
{Mergefield somefield}{IF{Mergefield Spouse} <> "" "
{Mergefield Spouse}"}{IF{Mergefield Someotherfield} <> "" "
{Mergefield Someotherfield}"}etc
Then the line feed and the field are only entered if they have content.
Insert the field boundaries with CTRL+F9

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Graham Mayor - Word MVP
My web site www.gmayor.com
Word MVP web site http://word.mvps.org
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> I am merging from Excel into MS Word 2003 to create a directory of
> employees and their home/work contact info. Where there is no data
> in Excel, such as spouse name in the case of an unmarried employee,
> Word leaves a blank line in the document. How can I avoid this?