Job hunting while pregnant is a bit of a struggle, but it is possible to get a new job while you are expecting a baby. Let's be honest though that, despite anti-discrimination laws, it is a lot harder. When you are at a job interview and the question about your family plans comes up in any kind of way, hinting that you are trying to get pregnant might make the difference between being hired or not. The general consensus among women who have tried this is not to mention anything (look at job hunting while trying to conceive for more on this topic). Once you are hired and appreciated for your abilities, a pregnancy will have much less impact on your further career within that company. And if you have already started a new (and hopefully exciting!) job, where does trying to get pregnant and recent career changes fit into the grand scheme of things?
Once again, a pregnancy might well affect your career, more so than if you had been employed in the some place for a long time. Perhaps trying to get pregnant and wanting to make a career change presents the ideal opportunity to seek out flexible, family-friendly employers. Some workplaces are happy to provide their workers with the opportunity to work from home some of the time, work part-time, or even take some time out. Some places of work offer more holidays (think educational institutions, for instance) than others. Now is the time to explore!