Stages of labor - physiology

Summary

This comprehensive overview of labor and delivery details the stages and physiological processes involved in childbirth. It begins with the definition of labor, highlighting the onset and signs preceding true labor. The script outlines the three main stages: the first stage with cervical dilation, the second stage focused on the baby's passage through the birth canal, and the third stage involving the delivery of the placenta. Key factors such as fetal presentation, lie, and attitude are discussed, emphasizing their impact on the delivery process. Overall, the content serves as an informative guide for understanding the complexities of childbirth.

Takeaways

• 😀 Labor, or parturition, is the process of delivering a baby, starting with uterine contractions and ending with the delivery of the placenta.
• 👶 True labor contractions begin when the fetus is considered full term, typically between 37 and 42 weeks gestation.
• 🩸 The onset of labor can be signaled by the release of a mucus plug (bloody show) or the rupture of the amniotic sac (water breaking).
• ⏳ Labor can last about 12 to 18 hours for first-time pregnancies and around half that time for subsequent pregnancies, though this varies.
• 📏 The first stage of labor is subdivided into two phases: the early (latent) phase and the active phase, with significant cervical dilation occurring.
• 💪 Contractions in the active phase become very intense, lasting 60 to 90 seconds with short breaks in between.
• 🌀 The second stage of labor, known as the pushing stage, focuses on the baby's head navigating through the maternal pelvis.
• 🔄 Several factors affect fetal passage, including fetal size, attitude, lie, and presentation, which are crucial for a successful delivery.
• 🏋️‍♀️ Cardinal movements of labor include descent, flexion, internal rotation, extension, restitution, and expulsion.
• 🍼 The third stage of labor involves the delivery of the placenta, followed by a fourth stage where physiological changes occur as the body adapts post-delivery.

Q & A

What is parturition?

Parturition, commonly known as labor, refers to the process of delivering a baby, which includes uterine contractions, cervical changes, and the eventual delivery of the placenta.

When does labor typically begin?

Labor usually begins when the fetus is considered full term, which is between 37 and 42 weeks of gestation.

What are the signs that labor is starting?

Initial signs of labor include the loss of the mucus plug (bloody show) or the rupture of the amniotic sac (water breaking).

What distinguishes true labor contractions from false labor contractions?

True labor contractions are characterized by increasing frequency, duration, and intensity, whereas false labor contractions, known as Braxton Hicks contractions, are milder and ineffective.

What are the stages of labor?

Labor is divided into three stages: the first stage (from the onset of contractions to full dilation of the cervix), the second stage (the pushing stage leading to the birth of the baby), and the third stage (the delivery of the placenta).

What happens during the first stage of labor?

The first stage of labor includes two phases: the early phase, where the cervix dilates from 0 to 6 cm, and the active phase, where it dilates from 6 to 10 cm with intense contractions.

What are the 'three P's' that affect the second stage of labor?

The 'three P's' are Power (the strength of uterine contractions), Passenger (the fetus), and Passage (the birth canal).

What is fetal presentation and why is it important?

Fetal presentation refers to the first fetal part that descends into the pelvic inlet, with cephalic (head first) presentation being ideal for delivery. It affects the ease of the delivery process.

What occurs during the third stage of labor?

The third stage of labor involves the delivery of the placenta, which occurs after the baby is born. The uterus contracts to help separate the placenta from the uterine wall.

What physiological changes occur in the fourth stage of labor?

The fourth stage of labor occurs postpartum, involving major physiological adaptations such as blood loss management and the beginning of uterine involution, where the uterus returns to its pre-pregnant state.