Essentially, it means a woman who has experienced her first menstrual period and is now within the reproductive years.
Here's a breakdown:
* Menarche: The first menstrual period.
* Postmenarcheal: The time period after menarche.
Example: A 15-year-old girl who has had her first period is considered postmenarcheal.
Note: The term "postmenarcheal" is often used in medical contexts, particularly when discussing conditions or treatments that are specific to women who have reached puberty and are capable of becoming pregnant.