The test you are talking about is probably an amniocentesis. An amniocentesis is when amniotic fluid is extracted from a women's uterus using a needle, but it is usually not done until after 15 weeks of pregnancy. I personally would not have this test done, because like every test, having an amniocentesis done comes with its own set of risks (miscarriage, injury to the baby or mother, premature labor, etc).
I would also never even think about aborting a child just because they could potentially have PKU. Whenever a woman gets pregnant they need to understand there is ALWAYS a chance that their baby will have a birth defect. Aborting every child who has something 'wrong' with them seems wrong to me, because no matter what you do you can never guarentee that your child will be 100% perfect. Even if a baby does not have PKU there is no telling if that baby will or won't be born with a different disorder such as down syndromes, spina bifida, other metabolic disorders, etc. This is just my opinion, but if a woman is really that afraid that their baby could potentially have PKU then they should simply not get pregnant again. But that isn't to say that there aren't people throughout the USA and the world that do abort their children when they find out they have a birth defect.
Although PKU does come with its ups and downs it is not a death sentence nor is it a horrible disorder that dooms us to living awful lives. Many of us on this website that have PKU are happy, healthy, and completely functional. Several of us have or will go onto college, get married, and have children.
To be completely honest if I had to choose a disorder for my future children to have I would much rather that they have a disorder like PKU, because PKU is completely treatable. Sometimes we get so caught up in complaining about how rough life can be that we forget there are parents in this world who would give an arm and a leg if their children's disorders could be treated with a special diet.