Home pregnancy test are reliable methods for confirming pregnancy status. If your test was negative, you are most likely not pregnant. A missed period is the first sign of pregnancy, but is not a proof-positive sign. Only a pregnancy test and a vaginal ultrasound remain the relevant diagnostic tools for detecting early pregnancy. Your period can be delayed due to a hormonally active ovarian cyst (fairly common). In this case, abnormal growth of a follicle (instead of ovulation) can develop a follicular cyst. This cyst produces estrogen that stimulates the endometrium and delays menstruation. If your period doesn’t come in 2 weeks, you can go to a gynecologist to identify the cause for lack of menstruation.