This is an interesting question that I am not sure I completely understand. If you mean that, after your blood pressure was checked repeatedly, you had vaginal bleeding/spotting, then it is extremely unlikely to be related to the blood pressure checks. If you mean that your arm itself had some discoloration or mottled spotting after being checked so many times, then it is possible that the blood pressure cuff did cause some bruising just from being repeated so many times.
Now to address your question about how many times it can be done, it is generally correct to say that it can be done many times over a day, as long as there is adequate time for the blood flow to resume in between each cycle. In the hospital, as you undoubtedly know, we will check blood pressures every 5 minutes when we are concerned about a patient's well being changing quickly over time, as the blood pressure is an excellent measure of some parameters of patient well being. T
here are, however, some patients, including those with a history of trauma or surgery
to the arm, who might not be appropriate to have their blood pressure checked even one time, which would be important to know. Please talk to your physician if you have further questions/concerns or this spotting continues.