medically speaking, abortion describes the termination of a pregnancy. as a technical term this includes spontaneous miscarriage or early pregnancy loss, which is why records may report a patient's medical history as including a prior abortion without a history of medical or procedural induced abortion.
abortion (spontaneous and otherwise) has existed as long as pregnancy and represents a natural part of the life cycle. the human body can miscarry as a result of fetal abnormalities: early pregnancy loss occurs in about 10% of clinically recognized pregnancies and about HALF of all early pregnancy loss results from fetal chromosomal abnormalities. the research in this field has a ways to go and there's still a lot to be learned about how spontaneous pregnancy loss is induced.
the process of experiencing a miscarriage can resemble that of an induced abortion. someone experiencing an early pregnancy loss in the first trimester up to about eight (8) weeks gestational age, before the embryo becomes a fetus, may experience cramping and bleeding in the hours leading up to and while passing the products of conception. not yet a fetus, this villi looks similar to a fluffy cotton ball in pathological analysis, using a water medium and visual exam. similarly, a person using a mifepristone and misoprostol-based method to end a pregnancy (often known as "medication abortion") around this timeframe can expect cramping and bleeding as the regimen takes effect before passing the tissue.