Merck Manual

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Stages of Labor (1)
Stages of Labor (1)
Stages of Labor (1)

Initial (Latent) Phase

  • Contractions are irregular at first but become progressively stronger and more rhythmic.

  • Discomfort is minimal.

  • The cervix begins to thin and opens to about 1 1/2 inches (4 centimeters).

  • The initial phase lasts an average of 8 hours (usually no more than 20 hours) in a first pregnancy and 5 hours (usually no more than 12 hours) in subsequent pregnancies.

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Labor