The first stage of labor lasts about how long for a primipara?

• A. 2-4 hours
• B. 6 hours
• C. 20 hours
• D. 12.5 hours

Answer: (D)

Understanding the duration of the first stage for a first pregnancy centers on recognizing that labor is divided into stages, with the first stage lasting from the start of regular contractions to complete dilation to 10 cm. In a first pregnancy, this stage typically runs about half a day, with many sources citing an average around 12 hours. That’s because the latent portion of this stage—early, evolving contractions and cervical changes—often unfolds more slowly in first-time labor, followed by a more brisk active phase as dilation progresses.

Choosing a value near 12.5 hours fits the common expectation for primiparas. Times like 2–4 hours or around 6 hours are shorter than is typical for a first labor, while 20 hours is longer than average, though variation exists and some individuals may experience longer durations. The take-home is that 12.5 hours reflects the commonly taught expectation for the first stage in a first pregnancy.