Hi When did she last have her period? If your partner has regular menstrual cycles of 26-30 days, then The first week and the last 10 days of her menstrual cycle are safe period. If you had sex during this time then there is no possibility of pregnancy. Even the precum contains sperms. So If you wish to avoid pregnancy consult your GP/ doctor and take emergency contraceptive pill. Even Intrauterine contraceptive devise can be inserted as a method of emergency contraception. It has the advantage that it can be continued as regular contraception. I have an advise for you if you wish to avoid pregnancy in future. Use contraception like birth control pills or intrauterine contraceptive devise as they are more effective than emergency contraception in preventing pregnancy. In addition Please use barrier contraceptive methods to protect yourself from sexually transmitted diseases.