Not bad for a first flash
Alright, this isn't bad for a first attempt.
The animation quality varies from shot to shot. Although things generally look pretty clean, the illusion of life is often missing. Adding in little details will probably help make hour characters feel a bit more real. A blink here or there, a nose scratch... something. Take a look at Don Hertzfeld's work for an example of how to make simplistic figures a little more life like.
One spot in particular that could use some work is when the woman starts eating the guy. I know that if some woman was attempting to bite a few hunks of flesh off of me, I'd probably react. This dude just sits there. You could have some fun with it. Have him running around the house while she takes bites out of him. Maybe she tries to take a nibble while he's asleep. You could have her slowly work up to it, first kissing him, then biting slightly; and he's getting a little excited; then she moves down his neck and goes for the jugular and he runs around screaming and bleeding until he dies, and she eats him. Don't just have him stand there though, it's simply not that interesting to watch and just a bit off putting.
I also think you should push your joke further. I get what you're trying to get at, but you need to develop the concept a little bit further. If you want to focus on the birth, you could do some funny fetal shots of the child. If you want to focus on the child, you could have a couple scenes of it growing up. Maybe it plays in the park, or goes to school (I could see a piece of it dropping off onto a test). Hell, you could have it playing in the road and getting smashed by a car, that'd be pretty funny. At this point it just comes off as strange without any real punchline.
You might want to add a bit more color into the backgrounds. Even adding a light gradient from gray to white would help. Just leaving a white background generally just comes off as being lazy. Adding a couple details might help too, but you can still keep it simple and make it work, you just need to toy around with it.
You may also want to think about adding a bit of ambient noise. It's particularly noticeable at the beginning, when they're just hanging on the couch doing nothing and suddenly decide to make out. Maybe a TV could be on in the background or something, but just having them sit there not speaking on the couch and randomly having them make out just doesn't work that well.
For the record, a suppository is a pill that is inserted into the rectum, it doesn't make someone go to the bathroom. What you're thinking of is a laxative.
Lastly, you may want to add a few more jokes to your next cartoon. This work, while it does show creativity and some invention, simply isn't that funny. It's mostly just gross, and while shock/toilet humor can be very funny, you need to actually make a joke to make it work. This particular joke has been done before more or less (take a look at the Ren and Stimpy cartoon "Stimpy's Son" or the more recent "Stimpy's Pregnant" or a multitude of South Park episodes including anything with Mr. Hankey or the episode "More Crap" etc...). Don't assume that people are going to laugh just because a piece of turd is on the screen.
But, for a first effort, you could have done far worse. Good luck with your next cartoon!