How does labor start? How do we measure labor stages? A walk through the research

 Every human enters the world through a pregnancy that either ends with a vaginal delivery or a C-section. So every human on the planet has been through birth.  technically speaking. Given that shared experience, it seems like birth, the how and the how long of it, would be a topic with a lot of relevance to many, many, if not all people. And, that maybe, we would understand what triggers labor and how to measure it's progress.But to date, there are lots of holes in our understanding of this critical process. What initiates spontaneous labor? What should labor look like? When does it officially start? How long should each stage last? These questions are really important, because they inform doctors about what to expect and how to manage labor. In today's solo episode, I try to walk us through current theories of the how and the how long of birth.Previous episodes about triggers for labor:Dr. Christina Herrera talks about the placental clock and how it relates to preterm birth: https://podcasts.apple.com/us/podcast/using-the-placental-clock-to-predict-preterm-birth/id1779600854?i=1000702829834Dr. Roger Young talks about how electricity moves through the uterus in active labor: https://podcasts.apple.com/us/podcast/how-new-research-on-uterine-contractions-could-revolutionize/id1779600854?i=1000681642524Dr. Yong Wang talks about how we can measure the electricity that moves through a contracting uterus:https://podcasts.apple.com/us/podcast/understanding-how-uterine-contractions-work-a-key/id1779600854?i=1000691330103 Dr. Polina Lishko talks about the electricity of labor at the cellular level: https://podcasts.apple.com/us/podcast/turning-labor-on-and-off-the-identification/id1779600854?i=1000713382865