While it's not necessarily a true comparison (a pregnancy that is started with IVF can end in abortion), the World Health Organization writes that only 29% of all pregnancies end in abortion. The percentage of IVF embryos with negative outcomes is significantly higher than the percentage of pregnancies that end in abortion.
Fertility clinics often offer gender selection and allow parents to test their embryos to "weed out" children with undesirable traits. Many other embryos are abandoned or killed simply because they are "extra." Estimates say that there are about 1 million frozen embryos in the United States alone, many of which have been abandoned.
