Not too long ago, it was commonplace for laboring women to receive an enema at Labor and Delivery wards. But guess what? Many women's bodies take care of the job of cleaning itself out before birth all by themselves. When your due date is approaching, or has already been and gone, you might get to the stage where you think you will be pregnant forever. Of course that isn't possible, but it can sure feel like it at the very end of pregnancy. Because of that feeling many women ignore the first few contractions and signs of labor, and think they are feeling a bit under the weather because of something bad they have eaten. Both of my labors started with diarrhea as well as regular contractions that kept getting closer together.
If you notice a sudden onset of diarrhea, watch out for other signs that labor is starting as well, and don't go anywhere! It might well be your body's way of making sure that birth will not include any "explosions" of an unwanted kind. And if you are still grossed out about this right now... You won't be for much longer. Poop might just become one of your favorite topics once your baby is here.