How accurate are Home Pregnancy Test?

Pregnancy test manufacturers say that home pregnancy tests are 99 percent accurate starting on the first day of a woman’s missed period.

But studies have shown that this number is probably a bit too high, considering that women’s reproductive systems do not all behave in the same way. 

Many women have irregular menstrual cycles, others ovulate at different times during the cycle, and some have fertilized eggs that take more time than normal to implant in the uterine wall.

In all these nonstandard cases, pregnancy takes longer than normal to begin, and taking a test in the very first days of pregnancy might return a negative result, not because the woman isn’t pregnant but because her pregnancy is running behind the usual schedule.

Luckily, there is an easy way to avoid any confusion and bring the tests’ accuracy closer to that 99 percent: wait several days before taking the test.

Studies have shown that by the first week after the missed period, implantation will have taken place in virtually all pregnant women, regardless of the regularity of their cycles, the moment of ovulation, or the time it takes for the egg to attach to the uterine wall.

Therefore, the accuracy of a test taken a week after the missed period will be extremely high.