The hormone hCG is produced in the earliest stages of pregnancy. During early pregnancy it plays a role in survival of the corpus luteum and has a significant role in the implantation of the blastocyst and protection of the embryo against immune attack at the fetal/maternal boundary. The hormone is initially produced by the embryo and therefore acts as a marker for its presence.

Levels of hCG rise rapidly and predictably in the earliest days of pregnancy and it usually first appears in urine 8-10 days (range 6-12 days) following the estimated day of conception when using the most sensitive laboratory assays.The levels of hCG in early pregnancy have also been found to be highly similar between women. This makes hCG an ideal urinary marker for quickly and accurately assessing whether a woman is pregnant or not.

Clearblue Pregnancy Tests can be used up to 5 days before the missed period

Published literature shows that hCG levels reach at least 50 milli-International Units per milliliter (mIU/ml) on the day a pregnant woman's period is expected.5-7 If a Clearblue Pregnancy Test is used on the day of the expected period, it is more than 99% accurate at detecting pregnancy. The high sensitivity of the Clearblue Pregnancy Test also means that pregnancy can be detected up to 5 days before the missed period. The graph below shows a typical rise in urinary hCG from the first detection of pregnancy.

The Clearblue DIGITAL Pregnancy Test with Smart Countdown contains an optical reader which provides clear digital results in words thereby eliminating the human error that can occur when reading traditional line tests.

The Clearblue DIGITAL Pregnancy Test with Smart Countdown also features a unique progress indicator (Smart Countdown) to reassure the user the test is working and indicate when they can expect the result to appear. It features the following important benefits:

It is the only pregnancy test that counts down to the result
It is over 99% accurate from the day of expected period
It contains a wide ‘no mess’, absorbent tip and integrated Floodguard™ Technology to help reduce the #1 reported usage error
It is sensitive enough to be used up to 5 days before the missed period
It provides a simple result in words: 'Pregnant' or 'Not Pregnant' for greater accuracy in consumers’ hands.

Clearblue Pregnancy Test 3 Pack