Hey there!
This was one of the more interesting questions asked here, so I consulted the other judges and we've come to a pretty unanimous consensus.
We want to let people get creative with what they want to make, and if you look back at the entries of the other jams, many are only questionably fetishy in nature. Similarly, we only specify that pregnancy has to play "a central role" to the games submitted, and we even tell people to give a warning if there is anything overtly NSFW in the games they make.
Therefore, you are free to make your celebration of pregnancy as you want - we will not wag our fingers at you if you don't include any NSFW/fetish-oriented content. Though, I should mention that your game may still be perceived as fetishy by members of the community - that's just part of the clientele, so to say.
Hope this helps, and good luck with the jam!