Most women don't know they're pregnant until they're six to seven weeks along.

Roe v. Wade allows an abortion to take place from conception until birth. Being for abortion in the United States means that, by definition, you're for killing the human/zygote/embryo/fetus/baby (a rose by any other name) at any stage in its development. That's how the Supreme Court defined it by making no distinctions. Once the baby's navel is out of the womb, it's not considered a fetus anymore. Until that point, you can kill it.

There are a few ways to kill the human/zygote/embryo/fetus/baby. You can vacuum it out when it's small enough. When it gets bigger, the doctor can grab the legs with an instrument and pull the baby down until the head is at an angle where the doctor can stab the head so that the brains come out. This makes the baby small enough to pass through the vagina.

The doctor can use an instrument to pull the baby's limbs apart and take out each part as it comes out.

Or, the doctor can inject a poison into the baby (abortionists call it "harpooning the whale"), and the poison burns the baby until it dies. Some mothers report that they can feel violent thrashing from the baby. A severely charred and dead body is then removed.

The last option is to remove the baby surgically, in one piece, and let it die, or induce labor. This is the least used option, as it's the hardest on the mother. In the past, the babies could be disposed of in the trash, or set on a table, until they died. Or drowned. It was legal to do anything. However, several years ago, a "Baby Born Alive" law was passed which stated that certain comfort care must be given to the baby until it dies if it is born alive. I think it's often about an hour, from what I've read. Though they can live much longer, as witnessed by the recent news about the six-month premature baby found alive in the morgue in Argentina.