There are many reasons you might miss a period. Simple things such as stress or exercising too much can cause a missed period and many girls are irregular during the first few years of menstruating. But if you've missed a few periods, be sure to see your healthcare provider.
Courts usually find probable cause when there is a reasonable basis for believing that a crime may have been committed (for an arrest) or when evidence of the crime is present in the place to be searched (for a search).
1. probable cause - (law) evidence sufficient to warrant an arrest or search and seizure; a magistrate determined that there was probable cause to search the house. evidence, grounds-your basis for belief or disbelief; knowledge on which to base belief; the evidence that smoking causes lung cancer is very compelling.. Reasonable suspicion of the presence of evidence of criminality, allowing the search of the person or premises for such evidence by authorities. 2. Reasonable grounds for believing a person is guilty of a criminal act, allowing the arrest, prosecution, or trial of such person.