Welcome to HCM,
You should know result of such sexual encounter depends on fertile period of female partner which I presume unknown to both ,usually it is 2 week prior to expected date of next period.
so if you do not want pregnancy
it is advisable to take Emergency contraceptive pill
like unwanted 72 or I Pill
Emergency contraceptive pill are successful most of the times,If you are worried too much just consult a Gynecologist He/She will guide you about EC.
You have to wait till her next period comes it means that she is not pregnant and by taking slight irregularity of period and bleeding is possible.if it is delayed by 1 week after expected date you can take a urine pregnancy test.
In future please practice safe sex
as it protects from unwanted pregnancy and also STDs.