I've had three pregnancies. DS is the happy product of pregnancy one, and I'm happily 20 weeks now. With pregnancy #2 I had a pap smear and a miscarriage. Completely unrelated I'm sure, but it made me say never again! My GP recommended it, my Ob when he saw I was overdue (before the results came back) was keen to wait until afterwards. As I said, probably completely unrelated (I was 6 weeks pg, bubs stopped developing at 6 weeks), but just the association wound up in my head.

The research would say it's completely safe but if you've had no history of abnormal smears, what's the problem with waiting - plenty of women don't have regular smears, just have it at 6 weeks.