Page 42 - 33Elctronic Book (3) Normal Labor

➢ The process of labor is completed spontaneously

➢ through the natural passage ( birth canal)
➢ The time of labor does not exceed 24 hours
➢ Without any complication to the mother or to the fetus

Factors affecting the progress of labor:

There are five essential factors that affect the process of labor :
Fetal factors:
Passengers: Fetus (Size of the fetal head, Attitude, position, presentation,

Engagement, Station) Placenta, membranes, umbilical cord, blood and amniotic fluid

Maternal Factors:.

➢ Passages: Pelvis, pelvic floor, uterus, cervix , vagina and vulva
➢ Powers :
• Primary power: contraction and retraction of the uterine muscles involuntary

• Characteristics of uterine contractions:

• Frequency or interval: The period between the start of one contraction and
the start of the next one.
• Duration: The period between the start of one contraction and its end.

• Intensity: The power or strength of the contraction.
• Phases of contraction: Each contraction has three phases:
A-Increment: A period during which the contraction begins slowly.

B-Acme: A period during which the contraction reaches a peak.
C-Decrement: A period during which the contraction diminishes.
- Secondary power: Refers to the power of the-abdominal muscles and

diaphragm, in the form of bearing down effort, which is partly voluntary and
partly involuntary, or reflex.
➢ Position: Maternal position affects her anatomic and physiologic

adaptations to labor. A woman in labor should be encouraged to find

positions that are most comfortable to her.

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