No ovaries but pregnant through FET

What are my chances of a spontaneous vaginal delivery?
I do not produce endogenous estrogen and I've read that dipping progesterone/rising estrogen help trigger labor. Can my placenta produce enough estrogen on its own to do all that is required? Has estrogen supplementation near delivery ever been tried in a case like mine?

Backstory: this is my third pregnancy, all without ovaries. The two previous ones went overdue. I had Braxton Hicks but contractions were never effective by themselves. The first two were cesarean deliveries ultimately. I still have hope of a VBA2C but am wondering if my body is just not capable due to my lack of ovaries.