I think you have to look at it from the other side, you built something and now are looking for people that use it.
What you'd want to do usually is to find people that have a need and then built something to solve that need.
So starting from that, who would want to use your service (expecting parents?) what do they do currently to solve that problem (naming books? other websites?) and how do they find that solution.
Once you clarified those questions in a lot more depth than you think necessary will it become clearer how to reach those people as well.
So starting from that, who would want to use your service (expecting parents?) what do they do currently to solve that problem (naming books? other websites?) and how do they find that solution. Once you clarified those questions in a lot more depth than you think necessary will it become clearer how to reach those people as well.