Traditionally abortion is understood as deliberate ejection of an immature fetus before it is viable outside mother’s womb. However, after the authentic interpretation issued by the Pontifical Commission for Authentic Interpretation of Legislative Texts on 13 May 1988, abortion includes also feticide; that is, deliberate killing a foetus within the womb anytime after its conception (cf. AAS 80 (1988) p. 1818).

One who procures abortion and all those who cooperated in procuring an effective abortion incur latae sententiae excommunication (cf. CIC, c. 1398, CCEO, c. 1450 § 2).

The penalty can be remitted by the ordinary of the place where the offender actually resides (CIC, c. 1355§2,). Diocesan bishop can grant the faculty to absolve from the crime of abortion to all priests to whom he has given the faculty in accordance with CIC c. 966 § 1. A priest cooperated in abortion is irregular for the exercise of orders (CIC, c. 1044, 3º). A person who has cooperated in abortion is also irregular for the reception of orders (cf. CIC, c. 1041, 4º). The Crime of abortion committed by member of an Institute of Consecrated Life must be dismissed from the Institute unless the dismissal is indispensable (CIC, c. 695). These penalties also existed in the 1917 Code.

Historically, right from the earliest times, church considered any intentional killing of human being a grave sin. Didache, for instance, insisted, “You shall not commit infanticide.” However, because of the misconceptions regarding the “ensouling” of foetus abortion was not a serious moral concern in the early church.

St. Augustine (AD 354-430) said, “ There cannot yet be said to be a live soul in a body that lacks sensation,” and held that abortion required penance only for the sexual aspect of the sin. He and other early Christian theologians believed, as had Aristotle centuries before, that “animation,” or the coming alive of the foetus, occurred forty days after conception for a boy and eighty days after conception for a girl. The conclusion that early abortion is not homicide is contained in the Corpus iuris Canonici.

At the beginning of the 13th century, Pope Innocent III wrote that “quickening”—the time when a woman first feels the foetus move within her – was the moment at which abortion became homicide; prior to quickening, abortion was a less serious sin. Pope Gregory XIV agreed, designating quickening as occurring after a period of 116 days (about 17 weeks). His declaration in 1591 that early abortion was not grounds for excommunication continued to be the abortion law of the Catholic Church until 1869. In 1869, Pope Pius IX officially eliminated the catholic distinction between an animated and a non-animated foetus and required excommunication for abortions at any stage of pregnancy

1917 Code of Canon Law also imposed latae sententiae excommunication reserved to the Ordinary for the crime of abortion (CIC, c. 2350). Similarly, those who procured actual abortion are also irregular for Ordination. However, according to this Code the abortion was deliberate ejection of an immature foetus before it is viable outside mother’s womb.