I've found that its my experience and skills that get me interviews (and therefore more work), and the certifications take second-place. While I can certainly recall times when someone has said "oh, you've studied XYZ", the XYZ doesnt normally clinch the deal. But, with that said, I'm always looking to keep my skills fresh, with or without a formal certification.
I dont think you should be too concerned about too many certificates, but it is important to bring the studies to completion. You mention a PM certificate but it sounds like you havent finished it yet; perhaps you wrap that up before embarking on the BA certificate, otherwise all the work is for naught if you dont conclude. If you read the recent article on this Modern Analyst website (Top 10 Key BA Trends for 2012), you will see that a trend for last year and this year (2012) is to be multi-skilled, therefore, having both BA & PM should serve you well.
Donald