Should Birth Control Pills Be Taken Exactly At The Same Time Everyday?

I was wondering about birth control...I try my very hardest to take them at the same time everyday but due to my work schedule there are days when I miss it by some hours. I have never skipped a whole day or anything but am worried since I am taking Lo Loestrine that maybe due to the low amount of hormones, I may be more suseptible to getting pregnent if the pills aren't taken at EXACTLY the same time and I just wondered if this was true or not?