Stages of Labor

Excerpt

Labor is the process through which a fetus and placenta are delivered from the uterus through the vagina. Human labor divides into three stages. The first stage is further divided into two phases. Successful labor involves three factors: maternal efforts and uterine contractions, fetal characteristics, and pelvic anatomy. This triad is classically referred to as the passenger, power, and passage. Clinicians typically use multiple modalities to monitor labor. Serial cervical examinations are used to determine cervical dilation, effacement, and fetal position, also known as the station. Fetal heart monitoring is employed nearly continuously to assess fetal well-being throughout labor. Cardiotocography is used to monitor the frequency and adequacy of contractions. Medical professionals use the information they obtain from monitoring and cervical exams to determine the patient's stage of labor and monitor labor progression.