A mother of three explains that she and her husband have been abstaining from sex in the four months since she gave birth, but they’ve been “having old fashioned makeout session to feel close to each other.” She goes on to wonder: “I keep having orgasms after he’s done ample nipple stimulation. Do I need to go to confession for this (and if yes, how do I awkwardly explain this to a priest?)” The answers ranged from “ask your priest,” to “you’re fine,” to the general consensus that it wasn’t a sin if it happened accidentally, but if you actively pursued orgasm this way, it became sinful.

This question, and hundreds of others like it, are the backbone of the Natural Family Planning (NFP) Facebook ecosystem. Groups exist for just about every niche subculture or belief you can think of, and ultra-traditional religious are no exception. You don’t have to be Catholic to practice NFP, but most are, because NFP is the Catholic Church’s official teaching and answer to contraception, or a way to semi-control the number and spacing of children without using hormonal birth control or barrier methods like condoms. In this particular NFP account, women (and it is mostly women, although a few men pop up every now and then) ask three main types of questions: Does this mean I’m fertile?, Is licit in the eyes of the Church? , and How do I deal with the emotional effects of practicing NFP? Women join these groups to find support as they navigate the complicated and sometimes conflicting rules around family planning as Catholics, only to be met with judgment or contempt when they admit they may be struggling. NFP groups, as you might imagine, are also where women go to police each other’s bodies and sexual lives.

NFP, sometimes called fertility awareness, is a method of birth control based on a woman tracking her body’s fertility through close observation of physical signs. Practitioners abstain from sex on days when they are fertile — if she’s “trying to avoid,” or TTA. In a sense, NFP isn’t particularly more “natural” than hormonal birth control pills, which consist of hormones already present in women’s bodies, or the withdrawal method, which doesn’t introduce any other substances into the mix. But for NFP adherents, their practice is different from even these methods because it can also be used to help achieve pregnancy, and teach women about their bodies and health.

Women use different systems for tracking their fertile and infertile (or “safe”) days. For example, using the Creighton or Billings methods, named respectively after the university and doctors who developed them, women examine and chart their cervical mucus each day to learn when they ovulate, each with slightly different instructions. Marquette is a more modern method, in which women pee on a stick which measures their hormone levels in the morning to find if they are ovulating. Finally, the symptothermal method combines cervical mucus charting and taking basal body temperature, or resting body temperature first thing every morning to confirm that ovulation occurred. Ovulation causes a slight raise in resting temperature. Women have used periodic abstinence to space out children through the Church’s history, but these methods are all more recent attempts to incorporate greater scientific understanding of ovulation and fertility and make NFP more reliable.

A typical Creighton method chart

Members of NFP Facebook groups are usually quick to remind each other that the method they are using is actually more reliable than “artificial” birth control, but the data doesn’t reflect this. According to the Department of Health and Human Services, fertility awareness methods carry about a 25 percent risk of pregnancy with normal (not perfect) use, although it can be more effective with many abstinence days and methods used together. For comparison, the chance of pregnancy with the pill is five to nine percent, 18 percent for condoms, and less than one percent for IUDs. NFP is even slightly worse than the pullout method, which carries a 20 percent chance of pregnancy.

Of course, for Catholic practitioners, the effectiveness of a method matters less than the theological reasoning. The Church gives theological justifications for NFP as a licit method of spacing children, as opposed to the pill, IUDs, condoms, or other “unnatural” methods. Pope Paul VI’s 1968 encyclical Humanae Vitae is the official document NFP users fall back on to explain their use of it, and its interpretation is often debated in Facebook comments.

Humanae Vitae describes marriage as a spiritual union between a man, woman, and God, in which they “generously share everything, allowing no unreasonable exceptions and not thinking solely of their own convenience.” Here Pope Paul VI hints at what he makes explicit later: Artificial contraception is a form of holding back, withholding natural fertility for the couple’s convenience.

The “marriage act,” as church documents refer to sex, specifically means penis-in-vagina intercourse with the man ejaculating inside the woman — basically, sex that could potentially lead to pregnancy. Following this encyclical, choosing to create a new life is not wholly up to the couple. They are obligated to complete the act “naturally” and trust that God will give them a child, or not, and be okay with that decision. In NFP circles, they call this being open to life.

So, what exactly is allowed? The Church gets pretty specific with bedroom instructions, although of course they’re always open to interpretation and depending on your orthodoxy, you might end up with a more conservative reading. As generally accepted by NFP, just about any sex acts are allowed, provided they end with penis in vagina, potentially pregnancy-creating intercourse. Women are allowed to orgasm, but only when accompanied by the “open to life” act. Arousal or orgasms in any context that doesn’t result in PIV sex is off the table.

So, does the woman engaging in heavy make-out sessions with her husband need to go to confession? Most of the commenters were in agreement: if it happened unintentionally, you’re okay. However, after the first time, once you knew it was a possibility, that’s a sin.

A typical insult in this community is accusing another of having a “contraceptive mentality,” implying that she is using NFP to avoid pregnancy.

Many posts in the private, 17,000-plus member group “NFP: Catholic Style” start out with some kind of question about their charts, which typically track mucus and menstruation or basal body temperature. Usually, women are trying to avoid pregnancy, and post a picture of their chart to ask for confirmation that they’ve ovulated, or that they’re safe to have sex. But, there’s a schism between members there primarily for advice on avoiding pregnancy and some of the more extreme users, who believe it’s immoral to try to avoid a pregnancy at all, except in the gravest circumstances.

Humanae Vitae refers to “serious reasons” and “just causes,” for avoiding pregnancy, but the preferred translation among the more extreme members of the Facebook group is “grave reason.” The Church doesn’t give a list of specific circumstances that are valid for avoiding pregnancy. For some Catholics, this means, as one user put it, “God understands your reasons. It's up to Him to judge. What is in your heart?”, so each couple can make the choice that they feel is right for their specific situation. For others, though, a lack of concrete reasons means an opportunity to police and shame women who are actively trying to avoid children.

A typical insult in this community is accusing another of having a “contraceptive mentality,” implying that she is using NFP to avoid pregnancy in the same way that she would with more common birth control methods. But, isn’t that the whole point? Even strict NFP adherents understand it as a practice, as the name suggests, to plan and space out children. With unclear instructions and rules that seem arbitrary at times, women using NFP can be caught in a loop of constantly feeling sinful, like they’re failing at a teaching from God. Yes, they avoid modern birth control methods that would make their lives easier; yes they chart their menstrual cycles diligently, but are they really open to life in their hearts? The teachings on NFP leave enough wiggle room that almost no woman can ever feel that she is actually satisfying the requirements.

Women frequently post to the group in a panic: Could I be pregnant from having sex on x day? What does this weird spike in body temperature mean? These questions are often accompanied by venting or fear about the reasons why a pregnancy would be difficult right now, because of money, other children, mental health, the physical toll of giving birth, or something else. Of course, these women do not consider abortion an option, at least publicly. Sometimes, the posts simply express frustration at the whole idea of NFP. “What's the point in learning another method when you're terrified to have sex because the thought of another pregnancy makes you want to die?” one woman wrote. Some women express solidarity in their anger and fear, “My pregnancies have very nearly killed me getting worse every time and my last one, baby four, was born premature and it was a struggle for us both.I literally have nightmares about pregnancy and death. Hugs and love to you.”

No matter how dire the circumstances or how clearly the poster expresses her anguish, some commenters are quick to admonish her. “Just pray; the pill and tube tying fails too!” one wrote. The responses are two-fold: First, they remind NFP users that they are better and more “natural” than women who use other forms of birth control, which they also falsely claim is even less effective than NFP. Then, they point out that if you’re making mistakes in your charting that could result in a pregnancy, you must not really want to avoid that badly, so have another baby!

With strict regulations on sex and sexuality, faithful Catholic women aren’t left with many options to safely prevent pregnancy. Although Pope Francis has been hailed as a liberal voice in the Church, he hasn’t made any moves to change official teachings on birth control, besides suggesting that faithful Catholics could potentially use condoms in Zika infected areas. Prospects for a healthier support system for Cathollic women seem slim, given these limitations. Obviously, women don’t have to use hormonal birth control or condoms if doing so makes them feel ill at ease. To be pro-choice and care about reproductive health, that also includes the choices of these women to practice NFP, or to totally leave the choice out of their hands and not track fertility at all. It becomes an issue when adherence to NFP becomes another way for women to police each others’ bodies and sex lives with a cudgel of shame and guilt.

Maybe as more women practicing NFP realize that others have the same concerns and anxieties that they do, they can channel their energy into working with women’s health groups that aren’t necessarily associated with Catholicism. Even if they continue to choose not to use birth control, working with secular sources who can better understand their bodies and issues might help erase some of the shame and guilt that arise from the judgement of these secluded groups. Ultimately, though, the only way to change this situation might be a change in church teaching, as many members of these groups are getting their feelings of shame directly from the church.

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Mary Meisenzahl is a writer interested in religion and technology. She has written for Mel, Curbed Boston, and Boston Magazine.