Hi, Thanks for posting in HCM. I understand your concern. Oral sex does not carry any risk of getting pregnant. Pregnancy is possible only when sperms come in contact with vaginal mucosa. However, since your partner has taken emergency contraceptive pill and also tested negative with urine pregnancy tests, pregnancy could be unlikely cause for delay in getting periods. She should have got her periods by 3 weeks after taking the pill. You need to seek medical attention for the cause for delay in getting periods by consulting Gynecologist at the earliest. She might require certain blood test to look for hormonal levels and an ultrasound scan to come to a possible diagnosis, following which treatment could be instituted. Hope the information provided would be helpful. All the best.