Process-of-Labor-NCM

PROCESS OF Labor

Definition of Labor

  • Labor is a coordinated sequence of involuntary, intermittent uterine contractions.

  • It expels the fetus and placenta from the mother's body.

  • Uterine contractions and abdominal pressure are crucial for the expulsion period of delivery.

  • Normal onset occurs when the fetus reaches mature age (38-42 weeks gestation).

Theories of Labor Initiation

  • Mechanism that transitions Braxton Hicks Contractions to strong contractions is unknown.

  • Labor initiation can sometimes occur prematurely (pre-term birth) or late (post-term birth).

  • Various theories have been proposed:

    • Hormonal Factors

    • Mechanical Factors

Causes of Onset of Labor

Hormonal Factors (EPPOF)

  1. Estrogen theory

  2. Progesterone withdrawal theory

  3. Prostaglandins theory

  4. Oxytocin theory

  5. Fetal cortisol theory

Mechanical Factors

  1. Uterine distension theory

  2. Stretch of the lower uterine segment theory

Estrogen Theory

  • Significant increase in estrogen at the end of pregnancy enhances uterine excitability.

Progesterone Withdrawal Theory

  • Progesterone inhibits uterine motility; its decrease leads to labor initiation.

Prostaglandin Theory

  • Prostaglandins, secreted from fetal membranes, increase with pregnancy, stimulating contractions.

Oxytocin Theory

  • Cervical pressure prompts hypothalamic release of oxytocin, enhancing uterine contractions.

Fetal Cortisol Theory

  • Increased fetal cortisol levels stimulate estrogen production, contributing to labor onset.

Mechanical Factors

Uterine Distension Theory

  • Uterus contracts when distended, explaining preterm labor due to multiple pregnancies or polyhydramnios.

Stretch of Lower Uterine Segment

  • Stretching due to fetal growth induces contractions.

Other Theories of Labor

Theory of Aging Placenta

  • Reduced blood supply from an aging placenta triggers uterine contractions.

Bradley Theory

  • Advocates for nutrition, prenatal exercises, and relaxation techniques during pregnancy.

Alexander Technique

  • Focuses on the effect of posture on labor.

Lamaze Theory

  • Employs organized lessons to improve posture and pain relief techniques during labor.

Hypno-Birthing

  • Believes pain can be minimized by reducing fear and tension through self-hypnosis techniques.

5 P's of Labor

  1. Powers

    • Uterine Contractions: primary force for moving fetus.

    • Maternal Pushing Efforts: urged during labor due to pressure from the fetus.

  2. Passage

    • Includes maternal pelvis and soft tissues segmented into inlet, midpelvis, and outlet.

    • Pelvis Types: Gynecoid (favorable for vaginal birth), Android (not favorable), Anthropoid, Platypelloid.

  3. Passenger

    • The fetus; involves skull structure, attitude, and presentation configurations.

  4. Presentation Types

    • Vertex, Breech, Shoulder.

  5. Psyche

    • Psychological factors influence labor outcome, emphasizing preparation and support's role.

Labor Process

Stages of Labor

  1. First Stage: From onset of contractions until full dilation (0-10 cm).

    • Early Labor: 0-4 cm

    • Active Labor: 5-8 cm

    • Transition: 8-10 cm

  2. Second Stage: Full dilation to birth of the baby.

  3. Third Stage: Delivery of the placenta.

  4. Fourth Stage: Recovery period post-delivery.

Key Assessments in Labor

  • Contractions: Timing, frequency, duration, intensity.

  • Pelvic Assessment: Station of the fetal head concerning ischial spines.

  • Interview: Understanding maternal psyche, values, and fears.