Why can't I find a job?

Is it because I was a stay at home mom for a year? My last job won't even hire me back! I worked there for over 6 years! I left on good terms and gave my two weeks notice. What could it be? I also had some difficulties with my pregnancy that required that I take an early medical leave. Then I went back to work for almost a year until I decided to stay at home due to a lack of dependable child care. Any suggestions?