Because the abortion debate often focuses on abortions relatively late in a pregnancy, it is easy to get the mistaken impression of the circumstances of a typical abortion.
As the graphic shows, government figures record that about 90% of abortions occur in the first trimester – the first 13 weeks of pregnancy. Only about 1% occur after week 20, which is roughly half way through the second trimester.
The bottom plot in the graphic shows how fetal weight typically grows over time. From this we can see that during the first trimester, the fetus is under 20 grams, or about one half of 1% of a typical newborn weight. At such a small size, the fetal brain is very far from what it will be at birth or even at seven months.
Thus the vast majority of abortions occur in a very early stage of fetal development.