Final answer:
The onset of true labor is typically indicated 1-2 days after the 'bloody show'. The dilation stage can last from 6-12 hours but varies widely, potentially ranging from minutes to days, and tends to be shorter in women who have given birth previously.
Step-by-step explanation:
The onset of labor is a complex process that can be difficult to predict precisely. However, certain events indicate its approach. Notably, the occurrence of a "bloody show" is a sign of forthcoming labor. This involves the expulsion of a mucus plug from the cervical canal, which typically happens approximately 1-2 days before the start of true labor. It's important to note that these indicators can vary from woman to woman.
When we look specifically at the dilation stage of labor, which involves the cervix dilating to 10 cm to allow for the birth of the baby, this stage can last vastly different lengths of time. Typically, it takes 6-12 hours, but the exact duration can range from minutes to days, especially influenced by whether or not the mother has given birth before, with subsequent labors often being shorter in duration.