Immediately upon fertilization, a hormone called begins to be released; pregnancy tests measure the level of this hormone in a woman's urine to determine pregnancy

Human chorionic gonadotropin (hCG)

Explanation:

Human chorionic gonadotropin (hCG) is the hormone which can be detected in the blood and urine of a pregnant women. This hormone is made by the placental cells. The blood test or urine test is performed to check the progress of pregnancy that is the development of the fetus. The placenta is the outer membranous layer which covers and protects the developing fetus.

one centimetre is equal to 0.01 metres