Hi..Thanks for the query..
First of all taking too many i pills not good..
The fertile period for conception for a 28 day regular periods is
between 9-19 days of cycle.. The remaining days are considered safe
for intercourse without running the risk of
pregnancy..
If you have intercourse in the above said days (safe ) you don't
have to take even i pills provided your cycles are regular and your
calculations are proper..
One more method to calculate safe period is going by the quality of
discharge..
Intercourse is safe during dry days. Intercourse during wet days
(slimy transparent discharge ) has the risk of pregnancy..
The reason for irregular and scanty periods may be taking too many
pills..
Also improve your general health so as to get regular periods..
Hope this information helps you .. Take care..