Natural Family Planning: A Good Alternative To Birth Control?

Sick of taking the pill? Been hearing a lot about natural family planning? Here’s what you need to know about fertility awareness based methods.

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I was in ninth grade health class at my public high school when a Baptist youth minister explained that there was no stopping God if He wanted me pregnant. It’s a vivid memory, and I’ve since questioned its validity because of how absurd it seems to me now. The man was bald, I think. In his mid-to-late thirties, if you can trust the age perceptions of a 15-year-old. He and his blonde wife stood at the front of the class and told us they had used not one, but two forms of birth control before realizing they were with child. Thus, our reproductive futures were simply in the hands of the Lord, and no amount of planning could prevent His will from being done. I was living in suburban Arkansas (a state that, in 2014, 2015, and 2016, ranked first in the country for teen birth rates, according to data from the Centers for Disease Control and Prevention [CDC]). This was abstinence education around 2002, part of the evangelical purity movement that took hold in the 1990s during a time of economic downturn, the AIDS crisis, and Nancy Reagan’s “Just Say No” campaign. The times were changing; we were afraid. To double down on conservative sexual mores was part of a larger religiopolitical trend, as Sara Moslener argued in Virgin Nation: Sexual Purity and American Adolescence. “Rooted in fears of national instability and civilizational decline, the idea of sexual purity has been most compelling at points in history when evangelical theologies of the end-times provided viable explanations for widespread cultural crises,” she wrote. These theologies link “sexual immorality with national insecurity and impending apocalypse” and position “the white, middle-class, heterosexual, nuclear, Christian family as the foundation of American national strength.” The shaming in this movement was strong for everyone, but it was heaped on young women with special zeal. Those who dared to go carnal with guys who were not their husbands were used in ungenerous metaphors: They were dirty tennis shoes, chewed-up gum. “In short, the purity movement attempts to scare teenage women into sexual purity,” wrote Amanda Barbee, a graduate of The Seattle School of Theology & Psychology who studied Christianity and sexuality. “The movement instills them with the fear that if they have sex before marriage, they will be rejected by their future husband, their family, their community, and even their God.” Or, as abstinence-only speaker Pam Stenzel so succinctly put it: “If you have [premarital] sex … you will pay.” Like a good Southern Baptist girl, I believed. Now, as an adult woman who works hard to deprogram her mind from the sex-negative, misogynist, (and, by the way, ineffective) garbage that was “abstinence education,” any time someone tries to sell me on their religion’s reproductive protocol, I want to melt into a puddle and Alex Mack my way into oblivion. Natural family planning (NFP), as the only form of contraception with the Roman Catholic Church’s stamp of approval, is no exception. But am I throwing the baby out with the bathwater?

What is natural family planning?

Merriam-Webster defines NFP as “a method of birth control that involves abstention from sexual intercourse during the period of ovulation which is determined through observation and measurement of bodily symptoms.” The United States Conference of Catholic Bishops adds a didactic flavor to their definition, describing it as “the scientific, natural, and moral methods of family planning that can help married couples either achieve or postpone pregnancies.” (Many Catholics and some Protestants consider modern forms of birth control like the pill and condoms to be unethical.) “In very general terms, natural family planning is a way of preventing or timing pregnancy without the use of artificial hormones or other reproductive technologies,” says Caitlin Elder, a practitioner of the Creighton Model FertilityCare System, one of the church-approved NFP methods. Elder has taught over 40 families how to monitor their fertility since 2007. When applying NFP, “A woman (or couple) monitors one or more biological markers that change over the course of a woman’s menstrual cycle and then uses the concept of periodic abstinence in order to either achieve or prevent pregnancy,” says Elder. Some basic ways that a woman’s fertility can be determined are through the tracking of cervical secretions, basal body temperature, the shape or texture of the cervix, and urinary metabolite hormone levels. Popular NFP methods use some combination of these and include:

  • Billings Ovulation Method: Fertility is determined by observing cervical fluid.
  • Creighton Model: Fertility is determined by observing cervical fluid.
  • Marquette Model: Fertility is determined by observing cervical fluid, along with a second sign, urinary metabolite hormone levels. The latter is measured through the use of a hand-held electronic (ClearBlue Easy) fertility monitor.
  • Sympto-Thermal Method: Fertility is determined by observing cervical fluid, basal body temperature (waking temperature), and other biological signs, such as changes in the cervix.

So, the rhythm method?

The rhythm method might be considered the OG of natural family planning. Dating back to the 1930s, it is arguably the most primitive of the fertility awareness based methods (FABMs). A World Health Organization (WHO) fact sheet, listing it alongside the old “pull and pray” method, labels typical practices 75 percent effective at preventing pregnancy. For comparison, the pill has an efficiency of between 92 and 97 percent as it’s commonly used. The rhythm method involves tracking a woman’s menstrual cycle to predict which days she will be fertile. While revolutionary for its time, the inconsistency of many women’s cycles means that the margin for error is especially large. (This explains the old joke: “What do you call people who use the rhythm method? Parents.”) Modern-day proponents of NFP, understandably, want to distance themselves from the rhythm method, as it is often misunderstood to be synonymous with other, more sophisticated FABMs. Since the rhythm method is also known as the calendar method or the calendar rhythm method, it would be totally reasonable for an outsider (or, really, anyone) to conflate it with the Standard Days Method (SDM), which, as a calendar-based method that does not track biological indicators of fertility, sounds to NFP-virgin ears like the same damn thing. But no! The WHO lists typical-use SDM efficacy in pregnancy prevention as 88 percent. That’s a whole 13 percentage points higher than the rhythm method! (The stat appears to have been pulled from this research article out of Georgetown University. Study participants were comprised of 478 women who self-reported having regular cycles, meaning most of their recent cycle lengths were between 26 and 32 days long.) For clarity’s sake, let’s see how the WHO distinguishes the two.

  • Standard Days Method or “CycleBeads”: Women track their fertile periods (usually days 8 to 19 of each 26 to 32-day cycle) using CycleBeads or other aids.
  • Calendar method or rhythm method: Women monitor the patter of their menstrual cycle over 6 months, subtract 18 from shortest cycle length (to estimate their first fertile day) and subtract 11 from longest cycle length (to estimate their last fertile day).

The Standards Days Method relies on a woman’s cycle being between 26 and 32 days long (so, again, a fairly regular cycle), whereas the rhythm method asks women to use information from their cycle lengths over the past half-year to come up with a window during which they’re most likely to be fertile.

The Church’s Favorite Birth Control

The American public latched on to natural family planning in 1932, when Chicago physician Leo Latz, MD, published The Rhythm of Sterility and Fertility in Women. The book was unique because it summarized the research of two gynecologists, Kyusaku Ogino in Japan and Hermann Knaus in Austria, who had been studying ovulation since the 1920s. Though working independently, each had come to the same conclusion: A woman typically ovulated from between 16 and 12 days before her period, and the ovum, if unfertilized, likely did not even live for an entire day. Until around this time, most doctors had wrongly timed ovulation. According to a history by Case Western University, they had concluded by studying animal behavior that the “safe period” for women—that is, the portion of the month during which they could have intercourse without risking pregnancy—occurred at the midpoint of the menstrual cycle. This is, in fact, a woman’s most fertile period. The decade brought the birth of “the rhythm” method, and a new hope: Finally, a woman’s freedom and health and a family’s financial well-being might not be hindered by an endless succession of unplanned pregnancies. “In marked contrast to its position on most lay medical practices, the medical profession welcomed the rhythm method as ‘a ray of light’ amidst the uncertainties of most contraceptive techniques,” wrote historian David M. Kennedy in his book Birth Control in America: The Career of Margaret Sanger. It was, he said, “the first real advance in contraceptive research in decades.”

In 1930, the Catholic Church had announced its stance on contraception. Pope Pius XI issued an official letter, Casti connubii (Latin for “of chaste wedlock”), reiterating the importance of wives’ submission to their husbands and the primacy of bringing children into the world, and banning new contraceptive technologies, linking them with “a new and utterly perverse morality.” This was in response to the Anglican Church’s Lambeth Conference the same year, where contraception was approved in certain instances. (As some salty Catholics tell it, Anglicans eventually “completely caved in, allowing contraception across the board.”) So the rhythm method was exciting also because it aligned with Catholic sexual ethics, being not “artificial,” but “natural.” Latz, who was a devout Roman Catholic, became an advocate of the Ogino-Knaus method, advising women with regular cycles who were looking to avoid pregnancy to practice abstinence for eight days—five days before ovulation, plus three extra days for good measure. Using this model, newfangled fertility gadgets like the Scientific Prediction Dial and The Forecaster were created to help with tracking women’s “safe” periods. Unfortunately, even when an engineer collaborated with doctors to create “a simple, foolproof calculator for the accurate application of the Rhythm” (the Rythmeter), the resulting product was neither simple nor foolproof. By 1942, The Rhythm had sold over 200,000 copies—but people were losing faith. “Experience had shown that few women had menstrual cycles regular enough to allow accurate determination of the sterile period,” wrote Kennedy. “After all the excitement it had caused at its introduction, the rhythm method proved an even less adequate contraceptive than the standard diaphragm and jelly.”

The Pill’s Surprisingly Catholic Roots

In the early 1950s, biologist Gregory Goodwin Pincus paired up with gynecologist and obstetrician John C. Rock to develop the hormonal birth control pill. Pincus apparently chose Rock because he was a well-liked Catholic not afraid to speak out against teachings of the church, thinking this might help their cause with the public. (Birth control activist Margaret Sanger said he was “as handsome as a god” and could “just get away with anything.”) It didn’t exactly work. In 1964, after Rock went to speak in Ohio to promote acceptance of the pill, Monsignor Francis W. Carney, director of the Family Life Bureau of the Cleveland Catholic Diocese, released a statement labeling him a violator of morality and accusing him of “using his strength as a man of science to assault the faith of his fellow Catholics.” And in 1968, Pope Paul VI sealed the church’s anti-contraception doctrine in his encyclical Humanae vitae (Latin for “of human life”), which expressed, among other fears, that “a man who grows accustomed to the use of contraceptive methods may forget the reverence due to a woman, and, disregarding her physical and emotional equilibrium, reduce her to being a mere instrument for the satisfaction of his own desires, no longer considering her as his partner whom he should surround with care and affection.” (I can appreciate the sentiment here, but would like to respectfully point out that, if a man is going to be a f*ckboy, he’s going to be a f*ckboy with or without the use of prophylactics.) Rock advocated for the Food and Drug Administration to approve the pill, and it did in 1960. He also advocated for the Catholic Church to remove its ban. Though there was a period when the issue was up for deliberation, church leaders ultimately decided that to change their stance would mean undermining the notion of papal infallibility, which was a big no-no. Instead, they—a bunch of men—decided to let women continue taking one for the team. (Or a dozen, as was the case with one of Rock’s desperate patients, who, by the age of 32 and in 14 years of marriage, had endured 11 pregnancies, one of which was a miscarriage, and the last of which was twins. As a result, she was left weak and exhausted and suffered occasional blackouts.) When Rock died in 1984, the New York Times described him as “a loyal Catholic” who attended mass daily and kept a crucifix above his office desk. Rock attributed his continued dedication to the cause of birth control, ironically, to a church mentor:

[Rock] became a target of bitter attacks by some who called him a renegade, and he did not succeed in changing Catholic theology. But he stimulated much discussion in and outside the church. When questioned about the rationale for his battle, he told friends that as a boy of 14 he was told by a Catholic priest in Massachusetts: “John, always stick to your conscience. Never let anyone else keep it for you, and I mean anyone else.”

Are fertility awareness methods a good alternative to other forms of contraception?

I became interested in FABMs when my best friend from childhood, a devout Catholic, started talking more about NFP as she geared up for marriage. I disagreed with the theoretical framework behind it, but certain aspects of it were appealing to me. Not having to take synthetic hormones daily (I’d stopped taking the pill in college because I believed it may have been compounding my anxiety and lowering my libido—though, admittedly, these could’ve had more to do with college life and a bad relationship), learning more about my body, increasing pleasure (protection is necessary for safety, but it’s not quite as fun as going without), and improving intimacy with a partner who would share the responsibility of learning about my cycle—all of these seemed, to me, holistic, and surprisingly feminist, aspects of what she described. (Again, the requirement for half of these being that one must not be sleeping with a f*ckboy.) But, really, was it as reliable as she said? The CDC ranks FABMs among the least effective forms of birth control, lumping them all together to amount to an unintended pregnancy rate of 24 percent within the first year of typical use, meaning 1 in 4 women using a FABM would become pregnant within a year. The WHO separates out FABMs to offer different statistics for each method—and these align more with the statistics given by NFP advocates, like FACTS (the Fertility Appreciation Collaborative to Teach the Science), a group that claims the federal government downplays the effectiveness of FABMs by conflating statistics and referencing limited, low-quality research. “Based on the most up-to-date and highest quality published medical research, the effectiveness rates of fertility awareness based methods (FABMs) with correct use are between 95 and 99.5 percent, depending on the method,” they say in a joint petition with Natural Womanhood for the CDC to update its statistics. “Even with typical use, the effectiveness rates of FABMs are comparable to most commonly used forms of birth control.” According to the petition, more accurate effectiveness rates for FABMs are as follows:

  • Sympto-Thermal Method: pregnancy rate with perfect use 0.4 percent, with typical use 1.6 percent
  • Marquette Method: pregnancy rate with perfect use 0 percent, with typical use 6.8 percent
  • Billings Ovulation Method: pregnancy rate with perfect use 1.1 percent, with typical use 10.5 percent
  • Standard Days Method: pregnancy rate with perfect use 4.8 percent, with typical use 11.9 percent

A German study published in 2007 found, indeed, that the sympto-thermal method (STM) had an effectiveness comparable to that of oral contraceptives, though critics claimed that the data was “cherry-picked” by researchers. They said that the level of complexity required in observing biological indicators of fertility accurately, combined with the length of abstinence suggested for optimal effectiveness, rendered STM less viable for the average couple, and suggested that religious affiliations may have influenced the study. This is a crucial point. It would be irresponsible to discuss the topic of fertility awareness methods without discussing today’s political landscape where ideologues are co-opting valid concerns about hormonal contraception to effectively limit women’s reproductive rights. The current administration wants to defund services that would provide women with the most rigorously researched contraceptive options to instead emphasize natural family planning. They’re also trying to resurrect the abstinence-only “education” that I received in high school. The best birth control for you depends entirely on you: your body, your habits, your priorities. The pill, the shot, and long-acting reversible contraceptives (LARCs) are among the simplest and most reliable methods. Many women choose to take these not only because of their effectiveness in preventing pregnancy, but also because of their ease of use. Set your phone alarm to chime every day at a set time, get a shot every three months, or have a very small device put into your uterus or upper arm, and that’s it! You’re set to enjoy pregnancy-free sex for the next four to 12 years. As far as pregnancy prevention goes, LARCs are the clear winner among non-permanent options, with between 98 and 99.9 percent effectiveness. They require the least maintenance, lasting for years without intervention. (It’s been characterized as “get-it-and-forget-it birth control.”) Some women rely on hormonal contraception like the pill to help with issues besides unwanted pregnancy, such as irregular or painful periods, premenstrual dysphoric disorder, migraines, acne, excessive hair growth, endometriosis, and polycystic ovarian syndrome. While hormonal contraception has been associated with a small increased risk of breast cancer, it has also been shown to strongly decrease the risk of ovarian, endometrial, and colorectal cancers, amounting to an overall reduced risk of cancer. (OB-GYN Jen Gunter, writing for the Marin Independent Journal pointed out that the recently released findings about the breast cancer–birth control connection should “be interpreted with caution as it doesn’t take into account breastfeeding [known to reduce breast cancer] and lifestyle factors associated with an increased risk of breast cancer, such as alcohol consumption and lack of physical exercise.”) When these options are blocked, women pay the price—especially poor women, who may not be able to afford the most reliable forms of birth control on their own. When it comes to statistics on FABMs, we have to ask ourselves: Who funded the research? What is the organization’s mission? Are they trying to promote FABMs to the exclusion of other contraceptive methods? The organization FACTS, for example, has no explicit religious affiliation, but its co-founder and executive director is Marguerite Duane, a board-certified family physician who, in The Federalist, argued that contraception isn’t necessary for women’s health and that resources should be reallocated to “truly critical medication.” Gunter, in a blog post, eviscerated Duane’s arguments, calling the article “an anti-science, misogynistic screed” and highlighting the dangers of limiting women’s access to the full range of birth control options. To get a better understanding of the disconnect between FABMs statistics offered by the CDC and organizations like FACTS, I reached out to Chelsea B. Polis, PhD, an epidemiologist who holds an associate appointment in the Department of Epidemiology at the Johns Hopkins Bloomberg School of Public Health. Though Polis believes that we need more research on FABMs’ effectiveness, she disagrees with the assertion that the CDC is withholding more accurate statistics. “Populations in clinical trials [such as those cited by NFP proponents as evidence of FABMs’ actual effectiveness] are more highly selected (and thus less generalizable to the wider population), and their behaviors may be impacted by frequent contact with investigators and study staff (this may be particularly true for methods that are highly user-dependent, such as FABMs),” Polis wrote in a blog post, wherein she outlined issues not addressed in the FACTS/Natural Womanhood petition. She included that “there are not enough episodes of use of each individual FABM to generate statistically stable estimates for each method separately.” “While I applaud the goal of FACTS to support medical providers to better understand FABMs, I am unfortunately not convinced that FACTS always approaches this goal in a non-ideological, evidence-based manner,” Polis tells me via email. “For several years, I’ve noted concerns regarding the scientific integrity of statements made by certain FACTS members, including Dr. Marguerite Duane. I wrote about some issues in this blog and linked to specific details in a Storify.” Storify has since shut down, but you can check out the contents here. “I found the FACTS/Natural Womanhood petition to be problematic in multiple ways, including what appears to be gaps in their understanding regarding certain scientific/methodological issues related to the estimation of contraceptive effectiveness,” says Polis. She then references Duane’s article for The Federalist, which, she notes, “caused an understandable uproar among many women’s health experts.” “Given FACTS/Dr. Duane’s propensity to make non-evidence based statements, from a scientific perspective, I would certainly encourage substantial caution around accepting their statements at face value,” she says.

I want better information on FABMs—what can I do?

Let’s say that you don’t have insurance or you’ve done a cost-benefit analysis with your doctor and decided against hormonal, surgical, and barrier methods of contraception or your country is turning into a dystopian hellscape where human rights are being eroded by fundamentalists who would like to take away your access to a variety of birth control options. Any of these situations might might mean you find yourself with questions about the effectiveness of FABMs. What can we do, we non-medical professionals who are interested in learning more about natural contraceptive options but who are skeptical of the existing research on FABMs, given how closely linked they are to powerful religious and political ideologies? There is “no single perfect answer,” says Polis. “I think the best approach is to seek out established professionals (or professionally created sources) who have a very strong scientific background and a reputation for sharing unbiased information on all contraceptive options,” she says. “Different kinds of resources meet different needs. Certainly, having a trusted reproductive healthcare provider to discuss your options with is a tremendous asset.” If you’re looking for a “quick, free, and user-friendly” resource that will give you digestible information about all your options, Polis suggests checking out the website Bedsider“If you prefer having lots of detail and citations, a book like Contraceptive Technology […] is an incredibly comprehensive, evidence-based resource compiled by leading experts,” she says. (The newest edition, updated for the first time since 2011, just came out in September.) Also in September, the journal Obstetrics and Gynecology published findings from a project that Polis and her colleagues have worked on for several years. “As far as I know, our review [is] the most comprehensive source available summarizing the quality and results of all prospective studies ever published on any individual FABM,” she says. They developed a framework for evaluating and ranking each study, and Polis believes their review “will shed a lot of light on what is known (and what remains unknown) about the effectiveness of various FABMs for pregnancy prevention.” In the meantime, how can we support research on FABMs without unwittingly bolstering policies that would limit women’s access to a full range of birth control options? “Raise your voice to advocate for funding to support high-quality scientific research on all contraceptive options (including FABMs); be active in your community and on social media in talking to people about the importance of contraceptive choice and scientific research,” says Polis. “And vote.”

Anna Cherry
Anna Cherry is the staff writer for Multiply. She's lived in a few different places, written in more, and is now back in the state of her birth (Missouri).