One of the most frustrating, hair-splitting, nerve-wracking parts of trying to conceive is the "two week wait" between the day of ovulation and the expected first day of menstruation. Despite the agony of waiting, home pregnancy tests (HPTs) are not sensitive enough to detect pregnancy until right around the time a woman has officially missed her period (three days after the usual first day).

On the Other: False Results Possible

Some HPTs can detect human chorionic gonadotropin (hCG), the hormone that indicates early pregnancy, up to five days before the missed period (or two days before the typical first day of menstruation). However, if taken too early, there may not be enough hCG in the woman's system to cause a positive test result. In other words, if you take a pregnancy test too early, it is possible to get a false negative.

Bottom Line

If you are trying to conceive and get a negative result from a home pregnancy test, wait a few days until after your period usually comes and take a second test. If the wait is driving you over the edge, consult your doctor about having a blood test for hCG. These are more sensitive than HPTs and can therefore give results sooner.

Source:

Baby Hopes: Can You Take A Home Pregnancy Test Before You Miss Your Period?

Ovulation Calculator: Pregnancy Test Sensitivity and Early-Detection Testing