JCJC Human Growth and Development Practice Test 2026 - Free Human Development Practice Questions and Study Guide

Stage 1 of birth focuses on cervical dilation driven by contractions. Regular, increasingly strong contractions cause the cervix to efface (thin) and open from closed to about 10 centimeters, preparing for the baby to pass through the birth canal. This stage includes the progression from early dilation through more active dilation and into the transition just before full dilation. The key feature here is the cervix opening, not the actual birth of the baby or the delivery of the placenta. Once full dilation is reached, stage 2 begins with the baby's delivery, and stage 3 follows with placental delivery. The idea that contractions end and labor ends does not describe this stage.