"once a zygote has implanted itself on the uterine wall, this signifies the end of the stage of development and the beginning of the stage."

"once a zygote has implanted itself on the uterine wall, this signifies the end of the "germinal" stage of development and the beginning of the "embryonic" stage."

Germinal Stage refers to the two-week time frame after conception. Conception happens when a sperm cell joins with an egg cell to frame a Zygote. Around thirty-six hours after conception , the zygote starts to partition rapidly. The subsequent ball of cells moves along the mother's fallopian tube to the uterus.  

The Embryonic Stage keeps going from the finish of the germinal stage to two months after conception. The creating ball of cells is currently called an Embryo. In this stage, all the real organs structure, and the embryo turns out to be extremely delicate. The greatest perils are teratogens, which are operators, for example, infections, medications, or radiation that can cause deformations in an incipient organism or embryo. Toward the end of the embryonic period, the embryo  is just around an inch long.

the fourth amendment protects:

"the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."  

so this would mean the denial to search and seizure without warrant or permission.