Playing the pregnancy card. This is especially effective once you are visibly preggers. People in general are remarkably nice to pregnant women, even strangers. They let you ahead of them in lines. They smile at you more and start pleasant little conversations with you about just about anything (not just about babies). Husbands give unsolicited backrubs (my favorite pregnancy perk).
All in all, it is a happy time and people just seem happy to be around you. What's not to love?