Hello thanks for using health care magic For sure, stress can delay someone s period. Pregnancy is usually a possibility to consider when ever a sexually active female misses her period or have a delay period. But that can only be possible if she had unprotected sex during her unsafe period. We are not certain of her unsafe period but from what you said, i.e. you had sex for 4 days from the 10 of June and she was supposed to see on 10th of July, though some ambiguity in the dates, i think pregnancy is less likely. However, pregnancy must still be ruled out by doing a pregnancy test with early morning urine. The best way of preventing pregnancy is being placed on a contraceptive method. Or in cases of unprotected sex, take an emergency contraceptive pill. Hope this helps. IF you have further query, i will be glad to help. Best regards Dr Achuo