Hi Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern...
Yes, Intake of Unwanted 72 can cause delayed periods. Actually delayed periods are common side effect of intake of
emergency contraceptive pill such as unwanted 72. Unwanted 72 contains levonorgestrol hormone which disrupts your menstrual cycle & cause delayed periods. Your periods could be delayed for 1-2 cycles.
As you have taken unwanted 72 within 24 hours of sexual intercourse therefore
pregnancy possibility is less in you.
Don't take unwanted 72 or an emergency contraceptive pill too frequently. Use condom or regular contraceptive pill regularly as method of
contraception in future. Regular contraceptive pill or condom are more efficient methods to prevent unwanted pregnancy & have lesser side effects. Emergency contraceptive pill can cause irregular bleeding & other serious side effects.
As there is no method of birth control which is 100 % effective, you should also do a pregnancy test to rule-out pregnancy possibility.
Refer to a gynaecologist for more queries
Don't worry you would be fine
Hope this information helps