Contact during safe periods and having menstruation there on almost always rules out the pregnancy. There are very very few chances like 0.00001% that a lady would be pregnant. To rule out pregnancy the best test would be serum beta HCG which is blood test of the pregnancy hormone to see what the levels are. Even a simple urine test done at home can rule out the pregnancy. So in safe period if you are having a contact then you don't have any chance of getting pregnant at all.

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