Many pro-life people maintain that certain forms of hormonal contraception—for example, the progestin-only “minipill”—can act as abortifacients by preventing implantation of newly conceived embryos. Advocates of contraception and abortion commonly reply with one or more of three objections.
The first is that it seems the birth control pill cannot cause abortions because women who use the pill still get pregnant and give birth to new babies. If the pill caused abortions, then this would not happen.
The second objection is definitional. The medical community defines the beginning of pregnancy at implantation, so some say that even if the birth control pill interferes with implantation, no abortion occurs because there was no pregnancy.
The third objection holds that no one really knows if birth control causes the death of an embryo because it would happen so soon after conception. If birth control fails, and if an embryo forms, dies, and is removed from the womb, there would be no physiological signal.
Explaining the Science
According to the Oxford English Dictionary, the definitive record of the English language, an abortion is the expulsion or removal from the womb of a developing embryo or fetus. Specifically, in medical terms, abortion occurs in the period before the fetus is capable of independent survival, occurring as a result either of natural causes, which is a spontaneous abortion, or of a deliberate act, which is an induced abortion.
The birth control pill, as well as other hormonal methods (shots, IUDs, patches, rings) works in three ways: 1) Prevents ovulation. 2) Inhibits sperm mobility through the cervix, in case ovulation occurs. 3) Interferes with implantation, in case fertilization occurs.
The primary mechanism works by using synthetic progestogen to suppress the release of gonadotropins. These hormones, released by the pituitary gland, are known as the follicle-stimulating hormone (FSH) and the luteinizing hormone (LH). In normal cycles, the pituitary gland signals for these hormones to spike. They stimulate the growth of ovarian follicles in the ovary and trigger ovulation. If these hormones are artificially prevented from spiking by the birth control pill, the ovary is prevented from releasing an egg. If there is no egg, there is no chance of fertilization. The primary mechanism does not cause abortion.
The secondary mechanism works by dehydrating the cervical area, thickening the cervical mucus and hindering sperm from reaching the fallopian tubes. Should the primary mechanism fail, the secondary mechanism could prevent fertilization. Hence, the secondary mechanism does not cause abortion.
It is the third, and admittedly lesser understood, mechanism that could cause an abortion. If the first mechanism fails, and an egg is released from the ovary, and if the second mechanism fails, and the sperm reaches the egg, and if the sperm fertilizes the egg to produce a zygote, then there is a new human life. This growing embryo will naturally seek to implant in the uterus of the mother to obtain the nutrients and oxygen needed for survival.
But the hormones of contraception will have also thinned the endometrium, or lining of the uterus. In a normal menstrual cycle, the endometrial lining builds up after ovulation as the glands and blood vessels expand. If an embryo is conceived and implants, this lining will become the placenta. Hormonal contraception interferes with this natural mechanism. Unable to implant, the growing embryo will die. This mechanism fits the definition of an induced abortion: the expulsion or removal from the womb of a developing embryo, occurring as a result of a deliberate act; in this case, the use of hormonal birth control.
Responses to the Objections
Regarding the first objection, it does not follow that the third mechanism cannot cause an induced abortion if birth control is not fail-proof. To concede that the birth control pill sometimes fails is not to concede that the third mechanism never causes an induced abortion. That is akin to saying that gunshots never cause death since people have survived gunshots. This is a fallacy of modal logic. Just because a proposition is sometimes true (embryos are sometimes not aborted by birth control), it does not follow that a proposition is never true (embryos are never aborted by birth control).
Regarding the second objection, this is of no importance. The mechanism exists independently of the definition. Whether one says that pregnancy begins at conception, which is the most logical beginning, or whether one says pregnancy begins at implantation when the embryo attaches to the mother’s endometrial lining, the fact remains that a new human has begun to live either way, and the developing embryo is deliberately expelled from the womb, causing its death.
The third objection is an appeal to ignorance, and it is insulting to a woman’s intelligence. It amounts to telling a woman: “Honey, don’t worry your pretty head.” One who seeks the truth cannot fear the truth, not even the tiniest seed of it.
Some Feminine Theology
To the above scientific discussion, allow me to add theological commentary through a woman’s eyes. To grant assent to the Church’s teaching that human life must be respected and protected absolutely from the moment of conception requires an unflinching commitment to both faith and reason. Our faith demands that we follow logic from start to end.
Those who use hormonal birth control are, in addition to artificially throwing off their body’s natural cycles, making the choice to deprive themselves of knowledge. They will never know whether their own children came to exist and were killed because of it, something that can never be undone.
If you have used hormonal contraceptives, facing this truth is hard. Understand it, own it, and then practice virtue. Do not doubt God’s mercy. You cannot know whether the third mechanism caused the death of a child, but you can offer your love and a prayer to whatever children may have been conceived, and you can entrust them to the mercy of God. If there were none, ask that your love go to children who have no one to pray for them.
Such an intention is to practice the intellectual virtue of prudence, to make the most of the available information. Practicing prudence means to seek honesty, to see things as they really are, to discern, to decide, to act, and then to have the courage to correct your choices when necessary. Prudence is the mother of all virtues because without truth, there can be no balance in justice. Without justice, we fight for the wrong things, and fortitude is misdirected as bravado. When we are not guided by goodness, self-restraint can do harm.
St. Thomas says that practicing virtue is the way to achieve our fullest potential, to be fully human. So, when it comes to a question like this: Does birth control cause abortion? The answer is simple: yes, it can, but you will not know for sure.
Where secular culture tells a woman to swallow a pill and wander about in ignorance, the Church tells her to claim her power as a rational and loving person.