1. Appearance and physical signs: It is usually not possible to directly determine whether a woman has had an abortion based on appearance, as the physical changes after abortion are not significant and vary from person to person.
2. Medical records: The most direct and accurate way is to access relevant medical records, but this involves personal privacy and cannot be accessed without permission.
3. Professional examination: Through professional gynecological examination, doctors may be able to infer whether there has been a history of miscarriage based on clues such as cervical morphology and endometrial thickness, but this is not absolutely accurate and personal privacy should also be respected.