When Is It 100%Q: When Is It 100%

A: A urine pregnancy test before you miss your period is not accurate enough to assure you that you are not pregnant. Probably more than 50-60% of pregnant women who do a home pregnancy test 11-12 days after ovulation will be negative at that time. But 98% will be positive 3-4 days after a missed period. So a negative pregnancy test 11-12 days after ovulation cannot tell you with certainty that you are not pregnant. A negative blood hCG test 12+ days after ovulation is usually more reliable than a urine test.