BE ate my response. You have to notify your employer of your pregnancy at the 15th week before the baby s due, you must have worked for your employer for 26 weeks by the time you get to the 15th week. So in English, you have to notify them by your 24th week of pregnancy, as long as you've been in the job for a couple of weeks before you fall pregnant you should be ok.
Good luck ttc xx
http://www.worksmart.org.uk/rights/if_i_go_for_a_job_interview