Flu shot while pregnant/breastfeeding

I'm looking for articles/studies/info on the pros and cons/risks and benefits of getting the flu shot while pregnant or breastfeeding. Would it be better to get it while pregnant or while breastfeeding or does it not make a difference? I'm REQUIRED to get it for my job which means it will either need to be during late pregnancy (8+ months) or before going back to work (when baby is about 8-10 weeks old). My OB did recommend I get it and I do plan on asking for more information from them, however I was wondering if any of you ladies have done some research on it? Also in case it matters I've never had any problems/side effects from the shot.

Thanks in advance!