Editor’s Note: The following is a moral analysis intended to help form the reader’s conscience. It is not intended, nor should it be construed, as medical or legal advice.

Q. My wife has polycystic ovary syndrome; and after consulting with her doctor, she was recommended to take the birth-control pill to control symptoms such as frequent and heavy bleeding. Is it okay to use the pill for this reason? If so, would we need to abstain from intercourse? I have heard about the moral principle of double effect, but I haven’t been able to find a solid answer on the subject. There seem to be many different opinions. Thank you.

A. The Principle of Double Effect permits the use of hormonal treatment for a proportionately serious reason when no better reasonable alternative is available, even if the treatment has an unintended sterilizing effect on the reproductive system. In that specific case, the hormonal treatment — although commonly called “birth control” — is intended to directly address a serious medical condition. The resulting sterilization is indirect.

Various methods of birth control are commonly prescribed to manage polycystic ovary syndrome (PCOS) because of how they act on the female reproductive system. The estrogen and progestin in the pill that you are asking about can be prescribed for birth control (temporary sterility, also called a contraceptive effect) or to address a hormonal imbalance that is causing PCOS (therapy). Even when prescribed to address PCOS, it can still have a contraceptive effect. In other words, we can identify two distinct effects when taking birth control to address PCOS. One is good (alleviation of PCOS symptoms) and the other is bad (temporary sterility).

This is precisely where the Principle of Double Effect comes into play. This principle has four essential criteria. First, the act must be morally good or indifferent. Second, the person must intend the good effect only, while merely tolerating the evil effect. Third, the good effect must not be brought about by the evil effect. Fourth, there must be a sufficiently serious reason to proceed, including a lack of better reasonable alternatives and a good effect that outweighs the foreseen bad effect.

I can gather from the information you provided that three of the four criteria are met:

1) The act of taking estrogen and progestin pills to treat PCOS is morally good.

2) You and your wife intend only the therapeutic effect of the hormone.

3) PCOS is not treated by the contraceptive effect, but by altering hormone levels in the body (which in turn may render her temporarily infertile).

Regarding the final criterion of a sufficiently serious reason, your wife must ask herself several questions: Has she explored and exhausted other reasonable alternatives for effectively managing PCOS, such as lifestyle changes or other low-risk medical interventions that will not make her temporarily infertile? This is critical from an ethical standpoint, since there is a growing number of options for identifying and treating most — if not all — gynecological health issues without the need for birth control. Is the good effect of treatment proportionate to the bad effect of temporary infertility? Is the good of managing PCOS and its symptoms proportionate to the side effects and risks associated with the pill? If so, then the Principle of Double Effect would apply. The PCOS treatment is direct while the temporary sterility that results from the pill is indirect and only tolerated, not intended.

The Catechism of the Catholic Church teaches that direct sterilization and contraception are always immoral regardless of good intentions:

“Legitimate intentions on the part of the spouses do not justify recourse to morally unacceptable means (for example, direct sterilization and contraception).”

It does not prohibit indirect sterilization. Likewise, the Congregation for the Doctrine of the Faith (now the Dicastery for the Doctrine of the Faith) definitively judged:

“Any sterilization which of itself, that is, of its own nature and condition, has the sole immediate effect of rendering the generative faculty incapable of procreation, is to be considered direct sterilization … such sterilization remains absolutely forbidden according to the doctrine of the Church.”

The teaching on direct and indirect sterilizations is also found in various papal writings. Two exemplary texts are the encyclical letters Casti Connubii (Christian Marriage) written by Pope Pius XI in 1930 and Humanae Vitae (The Regulation of Birth) written by Pope St. Paul VI in 1968.

We also can see the practical application of this teaching in the “Ethical and Religious Directives for Catholic Health Care Services,” published by the U.S. Conference of Catholic Bishops, which states:

“Direct sterilization of either men or women, whether permanent or temporary, is not permitted in a Catholic health care institution. Procedures that induce sterility are permitted when their direct effect is the cure or alleviation of a present and serious pathology and a simpler treatment is not available” (53).

This makes clear that the Church does not forbid recourse to valid medical treatments that may also render a person infertile.

As your wife discerns this treatment option, she ought to remember that ovulation and conception remain a possibility and do sometimes occur even when taking birth-control pills. Typical birth-control pills can also prevent the implantation of an embryonic child in the womb if ovulation and fertilization occur. This is called an “interceptive” action, resulting in the child’s death. Even though such an occurrence would be rare and not deliberately intended, it may be prudent for you and your wife to consider practicing a fertility-awareness-based method (FABM) of natural family planning to reduce the likelihood of such an occurrence.

Pope St. Paul VI affirmed the moral permissibility of avoiding pregnancy for serious reasons through legitimate means. The Holy Father writes in Humanae Vitae:

“If therefore there are well-grounded reasons for spacing births, arising from the physical or psychological condition of husband and wife, or from external circumstances, the Church teaches that married people may then take advantage of the natural cycles immanent in the reproductive system and engage in marital intercourse only during those times that are infertile, thus controlling birth in a way which does not in the least offend the moral principles which [are explained in the encyclical].”

By using an FABM, you and your wife can reduce the likelihood of any unintended interceptive effects of the birth-control pill. For information on FABMs or to find a Catholic health-care professional trained in these, both you and your wife could connect with the following organizations: FACTS about Fertility, St. Paul VI Institute, NaProTECHNOLOGY, SymptoPro Fertility Education, Couple to Couple League, Catholic Medical Association, Fertility Care Centers of America, My Catholic Doctor and FEMM Health.

Since the birth-control pill affects the menstrual cycle, however, it may make it difficult or impossible to identify when ovulation might occur. This is why consultation with a trained professional is particularly important. Even if it is too difficult to identify when ovulation might occur, the effort to work with a FABM professional — or at least a shared commitment to some form of periodic abstinence — may be pastorally prudent because of other benefits it can have for the couple, such as strengthening communication and avoiding the temptation of a “contraceptive mentality” when using the pill for a legitimate reason.

Finally, please continue to ask the Lord for his graces and wisdom through prayer and the sacraments. The Catechism (1785) reminds us that “in the formation of conscience the Word of God is the light for our path,” and we must assimilate it in faith and prayer. We must also examine our conscience before the Lord’s cross. “We are assisted by the gifts of the Holy Spirit, aided by the witness or advice of others, and guided by the authoritative teachings of the Church.”

John Di Camillo, Ph.D., Be.L., is the personal consultations director and ethicist at the National Catholic Bioethics Center.

Andrew Kubick, Ph.D., M.A., is a research fellow in bioethics and medical conscience at the Religious Freedom Institute and a personal consultations ethicist at the National Catholic Bioethics Center.