Why do some pregnant women choose adoption?

Some women are putting their baby's needs ahead of their own and do so out of love for the child.
Some women desire to give their child everything they are not able to provide at this time.
Some women want a stable, two-parent home for their child, and most adoptive families can provide this because they are secure financially and emotionally, and have been waiting to be parents.
Some women want their child to be able to go to college and have a wonderful education.
Some women want their child to have a large and supportive extended family for their child.
Some women realize their current situation is not the best for their child and do not want to struggle from day-to-day.
Some women already have children, and know that having another would hinder their ability to meet those children's needs as well as a new baby.
Some women do not have good, strong support from family or friends to help them with raising a baby, and cannot do it alone. To the contrary, some women have good, strong family support but do not want to rely on others to help raise the baby.
Some women don't want to try and raise a child with the birth father because he is not a good influence or because he is not supportive financially or emotionally, or both.
Some women recognize that the relationship, or lack thereof, they have with the birth father will make raising the baby too difficult.
Some women are scared and did not plan for this to happen in their life at this point. They want to find a way to bring the baby into the world and continue on with their goals such as education, employment, etc.
Some women are not ready to parent, but do not believe in abortion so adoption is a wonderful solution.