Deciding between niches

Hello, I’m in the LCS coach certification program right now, and I have a background as a birth doula. I’ve been working on the concept of my niche, which is to “teach high achieving pregnant women to use thought work to birth like a boss.” I have ample experience in working with birth so this made sense to me. However, I’m starting to get nervous about how my clients would measure their success, and that they would only work with me short-term, since after they’re no longer pregnant, they’d be done with me, unless I offer additional support postpartum. Also, why wouldn’t they just hire a doula instead of working with me?

I had the idea to focus on postpartum weight loss instead. I could help women to lose the baby weight while learning to love their new bodies and not starving themselves. I know I can do this because I’ve done it (lost 55 lbs, and I love my body, flaws and all, and I nourished and healed myself in the process). This niche would be measurable and I could more reliably do 3 month, 6 month programs, etc (as opposed to pregnancy with variable time frames).

Any thoughts on how I should proceed? My plan is that whichever niche I pick, I will be doing a podcast.