I used work as RN in fertility clinic in NYC for a few years, I still do per-diem shifts occasionally. Recently, the clinic hired FNP to join their practice. Maybe you do not necessarily need to be WHNP, maybe it varies by state. I know that many schools close their WHNP programs and just offer the Women's Health Cert in addition to the FNP. I think that any women's health related experience would help to "break in" (L&D, Post part, OB/GYN clinic)