Will a preg test work right 1 day before your missed period?

When you say work right I take it that means will it show if you are pregnant, rather than will it give a false positive? I tested positive 4 days before I was due and that was on a cheap test so it is possible. But don't be too disappointed if it is negative because it could be too early.

It could, but you're likely to get a false response. All pregnancy tests depend upon how much hcg is in your system & if it hasn't been long enough since you conceived (ie late ovulation, not everyone ovulates at 14 days/midcycle) the test won't work correctly. (When I was pregnant I just felt funny, but I had 4 negative test results before the last one, the 5th was positive.)

It's better to wait until after you miss your period, even to test the week after (sorry that's a killer). Or if you do test one day before & it's negative try testing again.

Good luck!

Yes