Guess what -- having sex might trigger labor!
Eh, probably not, but it's one of the activities (along with eating spicy food) that "they" say can help you on the road to delivery. And it's a fun one. So let your partner know it's time to get the ball rolling -- or at least have some fun trying.
Really, though, it's not a bad idea, since it'll be at least six weeks after the baby's born before you have the go-ahead for intercourse, and it may be even longer than that before you have the time or energy for a roll in the hay. So partners, take the initiative, since your lady might not be feeling too sexy these days. At best (or coincidentally), the contractions start. At worst, the two of you get your minds off the waiting game for a while.
Most certainly, the waiting game has most of your joint attention these days, and that's probably unavoidable. Still, you might as well put some of that mental energy to good, productive use …