Using a litter box comes naturally to almost all cats. First, anywhere it's pooped, use a product called "Natures miracle". You can get it at any pet store. Normal cleaning products will get rid of the smell so you can't smell it, but the cat still can. This stuff will take care of that. Until you do, his sense of smell is telling him that that's a "Make spot".
Second, if you see him going to make, place him in the litter box. I usually take some of the kitten's poop and put it in the box, then "show him"...place him before it, scratch his paws near it. They get it eventually. (You can actually see the little light go on in it's head. Probably a 5 watt bulb only!)
Is the litter box too tall? It shouldn't be past his stomach height. He may be having trouble getting in (like you climbing up on the dresser when you *really* need to use the bathroom...uncomfortable at the best of times!).
Are you using a good scooping litter and keeping the box clean? It could be a "kitty protest" if not.
Kittens are cute and fun, but pretty stupid. :) They will get it if you try a little though, since it plays into a natural behavioral trait.
Oh, you mentioned your pregnant...so if you have someone who can help with this, if you're worried, it may be a good idea. Otherwise, wearing a solid set of rubber gloves should take care of any medical concerns, and wash them thoroughly or toss them when done.
I actually had to train my second cat who wasn't trained to use a litter box, he was only 6 weeks old when we got him, it was so frustrating cause he went to the bathroom everywhere except the litter box, well what I did was as soon as he finished eating i would put him the litter box, he would jump right out and I would put him right back in and kept doing it till he would go to the bathroom in the litter box, it was frustrating but it worked and it only took a few days. I know being pregnant and all you don't want to be near the litter box to much but use some plastic gloves. Well thats what I did when I was pregnant. No one else would do it for me. Well hope I was some help..Good luck with your new kitty
put her in a kennel or a cat carrier with just a small box of litter. Only let her out to play (short periods of time) when you can watch her. That is how my friend trainned her cat.Took about 2 weeks.