Pregnancy and the Pill


Dear Mary Beth,

Thank you for your blog post about What the Church Really Teaches about Sex and Marriage. I have yet to see anyone mention the issue of contraception when it’s required because of certain medications a person may be taking. Are you familiar with the medication, methotrexate?

That is an excellent question—one that isn’t addressed nearly as often as it should be. And I am happy to answer it.

Yes, I am familiar with methotrexate. And I’m glad you mentioned it, because it is a very interesting drug, and particularly useful for this discussion. Methotrexate is one of the primary drugs used in chemotherapy. It is also used in lower doses for rheumatoid arthritis and other chronic inflammatory conditions. And, finally, it is the “abortion drug,” given to women with ectopic pregnancies and those who wish to terminate healthy pregnancies.

Methotrexate, obviously, is very dangerous to unborn babies. That’s why they administer it to women who want to end their pregnancies. If the drug is ineffective, it generally leaves the baby with severe birth defects.  That is why contraception (generally the birth control pill) is “required” for women taking the medication.

I don’t think anyone would disagree that it would be a very, very bad idea for a woman to get pregnant while taking methotrexate. But let’s talk for a minute about why the “requirement” that they take birth control pills instead isn’t such a great idea either.

First of all, just because a woman is taking the pill, that doesn’t necessarily mean she won’t get pregnant. This is true in two ways. First of all, the pill has a failure rate. That simply means that it fails a certain percentage of the time. And “failure” is defined as a woman getting pregnant. Estimates of the Pill’s failure rate vary, but a quick Google search just gave me a range of between 6% and 9%—every year. When you think about how many women are taking the Pill, that adds up to a lot of pregnancies. The odds that some of those women are taking methotrexate are, I’m sure, not insignificant. Those babies will almost certainly either die or suffer significant birth defects.

But the deeper problem lies in the way the Pill works. It doesn’t necessarily prevent pregnancy. The old pills did a lot better job of that, but they had horrible side effects. The modern birth control pill (with slightly less horrible side effects) works on what is called the “triple threat.” First of all, it tries to prevent ovulation. But it’s not particularly good at this. So it also thickens a woman’s cervical mucus, making it more difficult (but not impossible) for the sperm to get to the egg. And, finally, it changes the lining of the uterus, so that the any newly conceived baby cannot receive the nourishment necessary to survive and grow, and thus dies.

This last action is not contraception, it is abortion. It is not preventing the baby from being conceived—rather it is allowing the baby to be conceived and then killing it.

Nobody knows for sure how often this abortive action happens among women taking the Pill, but I’ve seen estimates all the way from once or twice a year up to 50% of a woman’s cycles. I have no idea which is true. What I do know is that to continue to use the Pill— with or without Methotrexate—knowing that such an abortion is possible is to be complicit with that abortion when it happens.

So what is the answer for women on Methotrexate? Well, we all know that there is only one 100% effective way to prevent pregnancy, and that is to abstain from sex. Short of that, anything we do to prevent pregnancy will come with some risk of “failure,” and thus some statistical possibility of pregnancy.

Short answer: if birth control is “required” for you to take a particular medication, know that any birth control method will have a failure rate, which means if you’re taking it and having sex, you still stand a chance of getting pregnant. And, if you’re taking the Pill, you may very well be getting pregnant without knowing it.

I can’t see where there is any answer, aside from good old fashioned abstinence.

Do you have questions for Mary Beth?  Write to her at



  1. Edel-72251 September 21, 2015 Reply

    There is never a need to take the pill. There is always an alternative medication with less side effects. To take the pill whilst using the principle of double effect is also immoral and a misapplication of that principle as the possibility of having an abortion is always a greater consideration. Do no harm is the heart of the moral law and our guide in all areas pertaining to morality.

  2. Apollo-1213244 June 2, 2015 Reply

    ” … aside from good old fashioned abstinence.”
    aside from old fashioned abstinence. – Yes
    But why the value judgement?

  3. MaryRose-1048166 January 29, 2014 Reply

    What a great article and suck informative comments. Thank you!

  4. Ella-964219 January 29, 2014 Reply

    Thank you for this well-written article, Mary Beth!

    Mark, while there is a “small” statistical chance of the pill causing an abortion, you are still are aware that there is a possibility of an abortion occurring, so you would be complicit in that abortion (I think there would be a moral culpability even if an abortion never occurred because you were open to that possibility). Natasha’s suggestion is a much more moral option.

  5. Marie-1035263 January 29, 2014 Reply

    Excellent article! And as a NFP instructor, I just want to add that in the extremely rare cases where a woman was (due to serious medical reasons) to take medications that could potentially cause an abortion, there are new methods of NFP that teach a woman to pinpoint her ovulation cycle (to the day – with a 24-48 hour window) so that she can avoid the potentiality of an abortion. Again, these are extremely rare circumstances. I truly believe that, in pretty much every circumstance, another medication that does not have these high risk factors could be supplemented. However, that is subject for another debate 🙂

    • Ann-1080387 June 3, 2014 Reply

      One should remember that intercourse does not have to happen on the actual day of ovulation for conception to occur. Sperm can survive inside the woman for about five days.

  6. Michael-1806 January 28, 2014 Reply

    Thank you and well done as always, Mary Beth. I was not aware of the ways in which the pill “worked.” Regarding the third way, I must believe that it isn’t advertised, explained or communicated much if it all. Truly, if it were seen as abortive in nature, many would not consider taking the pill.
    May the truth be revealed.
    And may we always choose life and honor the dignity of the person.

  7. Mark-687718 January 28, 2014 Reply

    Interest subject. As a man, I have to acknowledge that my ability to understand ALL of the complexities of this issue is limited. That said, it seems to me that the most morally responsible solution for a married Catholic couple would be to practice NFP, so they are making their best effort to avoid pregnancy in a Church-approved manner, AND for the woman to take the birth control as directed, to cover as much as possible the small chance of unexpected pregnancy during the remaining periods. As stated in the article, “it would be a very, very bad idea for a woman to get pregnant while taking methotrexate” due to the high risk of birth defects, so to not take the birth control, in my opinion, would be very irresponsible.

    • Natasha-1036143 January 28, 2014 Reply

      Is it really more responsible, Mark, for a woman to risk a chemical abortion than it is to abstain from sexual relations during her fertile period? There is a window of about 6 days each month during which it is possible for a woman to become pregnant. Even a married couple can abstain for that period of time. In fact, many NFP couples have stated that such abstinence strengthened their love for each other because they learned to express their affection for each other in new ways. Getting back to the point, though, this issue boils down to one question: is human life sacred?

      • Mark-687718 January 29, 2014 Reply

        Natasha, I think you must have misread my comment. My point was that in the above referenced situation, where the wife needs to take a drug for medical reasons that frequently causes birth defects and is therefore recommended to take birth control pills, the couple should practice NFP as their primary method of birth control (which should prevent pregnancy 98.2% of the time according to recent statistics) and the wife should ALSO take the birth control pills (to hopefully eliminate the remaining 1.8% chance of pregnancy). Yes, it is possible that the pill can result in a chemical abortion, but when you’re starting with only a small, 1.8% chance of pregnancy (thanks to the NFP), I would peg the woman’s chances of a chemical abortion at certainly less than 1%. To me, in this unfortunate situation, using the pill in conjunction with NFP is justified, but I respect those who think differently. I pray to God that I never find myself in that situation.

        • Natasha-1036143 January 29, 2014 Reply

          Ah, I see where the misunderstanding came in. So, just to clarify, allow me to re-state what I believe you’re saying: There’s a married couple, and the wife has a legitimate medical need to take a drug which can cause birth defects, so the doctor recommends birth control to prevent pregnancy. The couple wants to remain faithful to Church teaching, so they practice NFP, but just to be safe, the wife also takes the birth control pill. Is my summary correct?
          I’d like to point out several things about this situation. First, the 1.8% chance of still becoming pregnant while practicing NFP is due to variation in (pardon me) a woman’s monthly cycle. The basic premise of NFP is that the couple figures out when the wife is fertile and then the couple abstains from the marital act during that period.
          Secondly, contraceptives have a much higher rate of failure (to prevent conception) than NFP does–that is assuming that both are used as prescribed. The only way to be positive of preventing conception, is to not engage in the marital act.
          Thirdly, when making a choice like this, it is necessary to consider both the end (the purpose) and the means which are being used to attain it. My ethics professor at college (who was a faithful Catholic priest) said that if the means are intrinsically wrong, the end cannot make them right. Since abortion–whether accidental or intentional–is the murder of a human being, it is intrinsically wrong. Some birth control pills do cause abortions when an egg is fertilized. In fact, the effects of birth control pills do not always go away immediately after a woman stops taking them. Some women are finding that they cannot become pregnant and/or have a healthy pregnancy after being on the birth control pill. That’s a scary thought. (I would highly recommend looking into the other ways birth control affects women. Janet E. Smith is quite informative and interesting on the subject.)
          Lastly, if a child is conceived, it would not be in line with Church teaching to “get rid of it”, nor is it necessarily good for the family. I speak from experience here; my youngest sister has down syndrome, and she has touched more lives than you would believe possible. In fact, I know a number of families who have children with disabilities of various kinds, and in each case, that child has brought both the family and the community closer together. These children test their family’s patience, but they are also a tremendous blessing.
          As a final note, this comment is much too long and for that I apologize.

          • MaryBeth-278310 January 29, 2014 Reply

            Thanks, Natasha, for your “long” and well-thought-out answer. Just to add one short fact to sum it up for you, Mark. NFP works by interpreting the signs a woman’s body gives when she is fertile or infertile. The Pill introduces extraneous hormones into her system. I am not an expert, but it is my understanding that those hormones have the potential to “mess up” those signs, so that they can’t be read correctly. And hence NFP and the Pill cannot be effectively used at the same time.

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