Predictor Twin Pregnancy Test When a woman becomes pregnant, her body starts to produce a special hormone known as h CG (human Chorionic Gonadotrophin), which is present in the urine & increases daily. Predictor is uniquely designed to detect very small amounts of this pregnancy hormone in your urine, so you can test from the day that your period is due. The new generation Predictor test is now even easier to use than its predecessor. This new pregnancy test has symbols that show you how to proceed. You can therefore easily read the result in the window indicated by the symbol (T).