The launch of Gaia with a Soyuz rocket is the next launch planned from the ESA spaceport in Kourou as the launch of another Soyuz with four O3B satellites was delayed from September 30 to early 2014. If there will be an impact on the launch date of Gaia is currently unknown.
Update: At the moment the launch date for Gaia is remaining the same: November 20. There seems to be some pressure from the launch industry to move up the launch date. The current ESA position is to do the full testing and launch-preprocessing campaign for Gaia as planned including the time consuming and critical sunshield deployment test. My personal opinion is that ESA should insist on this position.