The majority of home pregnancy tests do not detect most pregnancies if used within the first day or two of a missed period, new research indicates. Despite the fact that many tests say they can be used on the first day of a woman’s missed period, investigators at the University of New Mexico at Albuquerque found that, among 18 tests, only one - First Response, Early Result - appeared to be sensitive enough to detect pregnancy in at least 95 percent of women on the first day of their missed periods.
