does this cite by jerry not undermine the premise of the thread?My understanding of the controversy surrounding this law is as follows.
Medical doctors in the US commonly calculate estimated gestational age from the first day of the last menstrual period, but they and others commonly calculate pregnancy itself from estimated time of fertilization, two weeks later, or implantation, three weeks later. Meanwhile, medical doctors can also determine a developmental gestational age by comparing the embryo or fetus to the average age of others at the same development level.
For purposes of abortion law, Roe v Wade introduced trimesters in relation to viability, but Webster was only concerned with viability. Some pro-lifers have fixated on 20 weeks as a time at which a fetus can feel pain, though medical researchers say a fetus cannot feel pain that early. More recent state laws have wished to push back the time of viability, often using the claim of possible fetal pain, and the "no abortion after 20 weeks" laws seem to be of this type. As I understand it, other state laws have banned abortion after 20 weeks of pregnancy using estimated conceptional or fertilization age to determine weeks of pregnancy - that would be 22 weeks' gestational age, but the Arizona law bans abortion from 20 weeks' gestational age, two weeks earlier than the other laws.
Medical doctors have objected to this Arizona law because science only estimates calendrical gestational age and later considers developmental gestational age by sonogram and developmental comparison. They take into account the fact that women can have irregular periods, etc. The law, however, is making calendrical gestational age definitive when science can't.
Second, both medical doctors and women have objected to this law because many serious fetal deformities cannot be determined until about 20 weeks' gestational age. Arizona also has passed an anti-wrongful-birth-lawsuit law that makes it okay for a doctor to fail to provide accurate information on the health status of a fetus to a pregnant patient. Hence, people who believe it is right to abort a fetus with serious fetal deformities will not be able to know about them within the time limit for abortion within the state, and Arizona doctors need not even tell the pregnant patient, making it more difficult to seek a timely abortion in another state.
At the same time, referring to gestational age rather than fertilization, implantation, or weeks of pregnancy in deciding time limits for abortion is different in law than in science, which only uses it for purposes of correctable estimation. There is no zygote at that time, let alone an embryo, and doctors know this. The legal reference does imply that women are pregnant at the gestational age, even though women are having their periods at the time and have not released in ovulation the ovum, have not engaged in the sex act that will provide the sperm that fertilizes it. Technically, it implies that every menstruating woman is already pregnant - and women rightly suspect that this could be just the first step in intrusive government monitoring of not only pregnant women, but all fertile women. It is really Nazi-esque.
"Pregnant" or "pregnancy" means a female reproductive condition of having a developing unborn child in the body and that begins with conception.