They say that labor is a marathon

But maybe pregnancy is more like other sports.  For example, temping and charting would be the off-season.  A pre-conception appointment would be like a scouting report.  Each pregnancy test is a round in the draft; even if you go late, a positive test means you made it.  First trimester is like spring training.  There's a chance you could still be let go or sent back to the minors, but the further in you make it, the lower the risk of that.  The first ultrasound is the first at-bat, all nerves, hoping things go well.  After that you're in a routine for a little while.  Then 20 weeks comes around with a halftime show: the anatomy scan.  You get to see a little flesh, heart-pouding excitement, and a little movement.  By the fourth quarter (30 weeks), you're ready to see how things are going to turn out.  And by the seventh inning (around 31 weeks), you really do need to stretch.  At the very end of it all, with a little blood, sweat, and tears, the game is over.  You may have to change your game plan depending on how things go, but one way or another, you get to your goal.  And therein lies the victory.

But then, that's mixing an awful lot of sport metaphors.