My period though early and timely.has gradually being scanty for couple of months now.it has. reduced from 5days to 3days,what could. be the problem?

Probably normal : If you have no other symptoms this is probably normal. More than likely it is a hormonal change. Continue to monitor but don't be concerned unless there is a new symptom. Please get your annual exam and talk to your physician about these changes. Good luck.

Likely normal: The nature of your periods can change over time. Sometimes they become heavier with more clots and cramps, sometimes they become lighter and shorter. If you are bleeding once a month it is probably just your period and the duration and intensity are likely normal for you at that particular time.