If your partner smokes, there's never been a better time to draw a line in the sand and ask him to quit. Studies have shown that babies of non-smoking moms who are regularly exposed to cigarette smoke are at increased risk for a number of health problems, including delayed growth, low birth weight, learning disabilities, behavioral issues, and possibly some childhood cancers. So buy your husband a patch and tell him it's time.
You should also make sure to steer clear of smoky bars and restaurants while you're pregnant, and ask other friends and family not to light up when you're around. Most people should be very understanding about not smoking in the presence of a pregnant woman.