In the
Bittersweets Series by Herself Buffy has two children while remaining an active slayer. It's also one of the best spuffy fictions out there. Spike's relationship with his little girl Jemima is one of the best things going IMO.
In
Baby Steps by Kallysten Buffy is still an active slayer. That story is not available online any longer however.
In the
Baby Series by Mrs Muir Buffy is an active slayer but the baby part of it doesn't happen for her for quite a long while in the series. It's a great series though.
In
Origins by Niamh Buffy is an active slayer (although the baby is Angel's in Spike and Buffy's care, it that matters to you).
There are other stories but these came to my off the top of my head, and are also very lengthy and well-written. Hope this helps.
