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Few hormonal birth control pills can lead to 1-2 missed periods. If you have missed more than 2 periods in a row, then it is abnormal and you should consider visiting your gynecologist for further evaluation to rule out pill induced ovarian suppression or secondary amenorrhea. Get started on treatment as indicated. If you have not been regular with your birth control pill intake and if you have missed taking 2 or more active pills, then you no longer remain protected and if you are sexually active, then chances of pregnancy also cannot be ruled out completely. Take adequate rest. Drink plenty of water. Maintain healthy diet and lifestyle.
Take care.