Brief Answer:
ipill is effective upto 95%

Detailed Answer:
Hello dear,welcome to healthcare magic.I understand your concern.
In my opinion ipill is effective if taken within 72 hours of unprotected intercourse.
So chance of pregnancy is rare.Relax.
The delay of period might be due to stress regarding the thought of pregnancy because
stress causes hormonal imbalance causing delayed period.
Pregnancy chances also depends on part of the cycle when intercourse was done.
So relax.It is just 4 days late .You can wait for a week or 10 days for spontaneous onset of periods.
After a week you can test for urine pregnancy test.If negative you can wait for spontaneous periods.
If result is positive or no period even after 10 days then you might consult gynaecologist for further management.
So avoid stress and wait for the period.
Hope this satisfies your query.
Feel free to discuss further.
Best regards...Dr srilatha

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