Efficacy of natural family planning methods

Modeling fertile window differences across the reproductive lifespan with quantitative urine hormone monitoring of the menstrual cycle

Bouchard TP et al., 2026 · Journal of ovarian research · Free to read

Reproductive hormones of the fertile window are often referenced to women in regular cycles, but this may not be representative of the hormonal profiles of women in different circumstances like polycystic ovarian syndrome, the postpartum period, and the perimenopause transition. This observational cohort study sought to identify the variability in the reproductive hormones in various clinical circumstances and to establish potential thresholds for each category based on hormone measurements with the Mira urinary hormone monitor. A total of 57 women (ages 22-51) in various circumstances (regular cycles, polycystic ovarian syndrome, postpartum and perimenopause) tracked Mira urine hormone measurements (estrone-3-glucuronide, luteinizing hormone, pregnanediol glucuronide), contributing 444 cycles of data. Using additive mixed models, hormone values were stratified by the four different reproductive categories. The perimenopause and polycystic ovarian syndrome groups demonstrated relative hypoestrogenic states, while the perimenopause group showed low luteal pregnanediol glucuronide and the polycystic ovarian syndrome/polyendocrine metabolic ovarian syndrome (PCOS/PMOS) group showed high luteal pregnanediol glucuronide. The perimenopause group had significantly higher luteinizing hormone values throughout the whole cycle. The fertile window hormone thresholds vary depending on a woman's specific reproductive category. Women in different circumstances should not necessarily use the same hormonal thresholds for the fertile window and ovulation. A larger dataset with ultrasound correlation to ovulation is required to delineate the fertile window with more precision. Hormone differences across the menstrual cycle could be used for targeted treatments in polycystic ovarian syndrome and perimenopause women.

Variations in ovulation time and menstrual cycle characteristics: analysis of a prospective long-term cohort study

Malliou-Becher MN et al., 2026 · Human reproduction (Oxford, England)

What are the variations in ovulation time and menstrual cycle characteristics among and within various individuals over the course of 12 menstrual cycles? There are considerable variations in both cycle length and ovulation time, with pronounced intra-individual variability over a 12-cycle observation period. Although it is commonly believed that healthy women have regular cycles with a predictable mid-cycle ovulation, more recent research shows a significant variation in cycle length and ovulation time. Previous studies have focused only on cycle length, often excluding cycles outside the 25-35-day range, thus limiting the understanding of natural variation; they have also lacked precise ovulation diagnostics or included small sample sizes, making it difficult to capture the full scope of cycle and ovulation variability. Similarly, a recent big data study, while valuable, was limited by a self-selected group and the absence of accurate ovulation diagnostics, reducing its generalizability. STUDY DESIGN, SIZE, This study was designed as a prospective long-term observational study, which involved collecting data from 1923 women with a total of 43 999 menstrual cycles from January 1985 to July 2019. After fulfilling the inclusion criteria, the main group consisted of 1051 women, all of whom contributed data for 12 cycles (12 612 cycles), including 420 conception cycles. PARTICIPANTS/MATERIALS, SETTING, Participants in the study were between 18 and 44 years of age at study entry and did not take any reproductive hormones. Women who were postpartum, breastfeeding, amenorrheic, or within a 3-month period after stopping hormonal contraception were excluded. Participants agreed to keep cycle records according to the symptothermal method, 'Sensiplan'. Ovulation time was determined using an evidence-based algorithm based on evaluating cervical mucus patterns and basal body temperature shifts, with ovulation time defined as the day before the temperature rise. Data analysis was descriptive, using absolute and relative frequencies, standard deviation, percentiles, and ranges. Age dependency was assessed using unpaired sample t-tests and one-way ANOVA. Linear regression was used to assess long-term trends. MAIN In 62.4% of women, cycle lengths varied by 1 week or more within 12 cycles. Accordingly, the time of ovulation varied by 1 week or more within 12 cycles in 54.8% of women, with 96.5% experiencing fluctuations of 4 days or more over the 12 months. The median spontaneous cycle length was 28 days, with a mean of 29.66 days (SD = 7.55). Only 52.7% of women consistently had cycle lengths between 23 and 35 days across all 12 cycles. Ovulation occurred most frequently between Days 12 and 16, with almost half of conceptions (45.7%) occurring after Day 16. A one-way analysis of variance revealed a significant reduction in mean cycle length with increasing age (P < 0.001), showing the shortest median cycle length of 27 days being in women aged 40-44 years. Age also impacted ovulation time, with women aged 35-39 years showing more stable ovulation patterns compared to younger women. Over the 34-year study period, average cycle length increased slightly but significantly (β = 0.0161, P = 0.0306), corresponding to approximately half a day. Intra-individual variability also showed a slight, but non-significant, upward trend (β = 0.0262, P = 0.2173). LIMITATIONS, Comorbidities such as hyperprolactinemia, obesity, and PCOS were not systematically excluded. However, by including only women with at least 12 cycles, the study largely avoided severe hormonal disorders. This study highlights the considerable individual variation of ovulation time and cycle length over 12 menstrual cycles. These findings contribute to a better understanding of fertility awareness, and highlight the implications for family planning and reproductive health management. STUDY FUNDING/COMPETING INTEREST(S): The authors declare no conflicts of interest. No funding was provided. N/A.

Hormone Changes in Polycystic Ovarian Syndrome Identified with a Personal Quantitative Urine Monitor: A Pilot Study

Bouchard TP et al., 2025 · Preprints.org · Free to read

Background/Objectives: Quantitative urine monitors are increasingly being used for a personalized approach to improve menstrual cycle knowledge and to manage fertility. Although several studies have evaluated urine fertility monitors in regular cycles, there is limited research in the use of quantitative monitors in reproductive disorders, such as polycystic ovarian syndrome (PCOS). Urine hormone data was collected with the Mira monitor from 20 participants, 10 of whom had PCOS and a matched group who had regular cycles. The main aim of this study was to evaluate the levels of luteinizing hormone (LH), estrone-3-glucuronide (E13G), and pregnanediol glucuronide (PDG) in PCOS menstrual cycles compared to regular cycles. Women with PCOS had higher BMI than regular cycling women (p=0.02). PCOS cycles were longer (p<0.05), peak day was later in the menstrual cycle (p<0.001), and luteal length was shorter (p < 0.01) compared to regular cycles. In whole cycle comparisons, E13G was found to be lower in PCOS cycles (p<0.01) and PDG was found to be higher in PCOS cycles (p<0.05). E13G was also lower in the follicular phase of and late luteal phase of PCOS cycles (p<0.00001). The results of this study demonstrate the feasibility of detecting hormonal differences in PCOS compared to regular cycles with at-home measurements with the Mira monitor. The metabolic dysregulation of PCOS is a possible factor in these hormone changes. Larger studies with different sub-types of PCOS will be needed to further clarify these changes and to understand the pathophysiology behind these hormonal changes.

The State of the Science of Natural Family Planning: A Report from NFP Scientists' Meeting Held in Orlando, FL, September 4, 2024

Manhart MD et al., 2025 · Linacre Q · Free full text on PubMed Central

A one-day meeting was held as a pre-conference to the Catholic Medical Association Annual Educational event in 2024. A panel of eighteen physicians, scientists, and researchers involved in NFP work was convened to review the available evidence in four topical areas: (i) evidence for effectiveness of NFP methods to postpone and achieve pregnancy, (ii) evidence for effectiveness in the postpartum and perimenopause transition periods, (iii) evaluate the current state of technology in NFP (specifically app and quantitative hormone monitoring), and (iv) evidence examining the impact of NFP on marital relations. In each topical area, the panel worked to reach a consensus opinion on the currently available evidence and identified priorities for further research. Results from these discussions and a set of priorities for further work are presented here. An expert panel was convened to review the current evidence supporting use of NFP in various settings, utilization of new technology, and the impact of NFP on marital dynamics. Results from these discussions and a set of priorities for further work are presented here.

Two methods of natural family planning

Billings JJ, 1980 · Am J Obstet Gynecol

Ovulation method of natural family planning

Connell-Tatum EB, 1981 · Fertil Steril

Past practices of Natural Family Planning (NFP) have included such techniques as: 1) calendar rhythm in which a constant mathematical relationship was calculated between the day of ovulation and the beginning of the succeeding menstrual period, 2) temperature rhythm in which sexual intercourse is permitted by observing that the basal body temperature rises at the time of ovulation, 3) a combination of calendar and temperature rhythm methods, 4) paper test strips which measure glucose and electrolytes in vaginal secretions, 5) electronic devices of various sorts which record changes in the potentials of the pelvic organs at the time of ovulation, and 6) recent developments in computer technology which measure a number of variables. All of these techniques depend upon the identification of the fertile and infertile periods of the menstrual cycle. More recent studies by the World Health Organization have analyzed the teaching phase of NFP and the effectiveness phase of NFP using the detection of ovulation by following changes in the quality of cervical mucus. These studies tested 869 women with varied backgrounds in 5 countries. The data support the fact that many motivated women can detect ovulation reasonably accurately by following changes in their cervical mucus (the Billings method), although teaching time and motivation are considerable. Long-term and detailed data are necessary to determine the value of these methods. The advantage of NFP is the avoidance of drugs and devices. Disadvantages are that demands are placed on the sex life of couples, and there are associations between failures and increased rates of congenital abnormalities.

Two methods of natural family planning

Hilgers TW, 1980 · Am J Obstet Gynecol

I read with interest the recent article by Wade and associates, "A randomized prospective study of the use-effectiveness of 2 methods of natural family planning: an interim report" (134: 628, 1979). In reference to the study of the ovulation method, the authors noted that abstinence begins on the 1st day of mucus secretion and continues until the evening of the 4th day beyond the peak or maximal mucus secretion. In the ovulation method, the peak symptom is not the same as maximal mucus secretion as was indicated in the paper. The peak symptom is defined as the last day of the mucus discharge that is clear and/or stretchy and/or lubricative. In the definition of peak symptom, the amount of mucus discharge is not specifically important and may often be misleading. I had the opportunity to do a site visit at this study at the request of the National Institutes of Health while the study was in progress. I analyzed several pregnancies which occurred in users of this ovulation method. Some of the pregnancies occurred as the result of poor teaching of the concept of peak symptom. In the ovulation method, proper understanding and teaching of that concept are essential to the measurement of its effectiveness. Noticeably missing from this interim report was any discussion of the quality control procedures which were utilized to guarantee a high-quality educational service to the people entered into the study. While the authors claim that the methods were taught by professional teachers, these teachers were actually women who had previously used the method and/or had formalized training in teaching the method. Simple use of either of the methods certainly does not qualify an individual to teach natural family planning. For those with formalized teaching, such training should have been outlined since judgment on the effectiveness of the teaching cannot be made; such a judgment is essential to the proper analysis of results. Finally, while the study claims to be a use-effectiveness study, it is rather a modified version of extended use-effectiveness. No objective definition of "user failure" is provided. One cannot ascertain how many pregnancies were related to poor teaching, nor can one tell how many occurred as the result of the couples' last minute exercise of their freedom to use their fertility. The use-effectiveness of the 2 methods under study as a means to achieve a pregnancy have been ignored. In doing so, the investigators have ignored use-effectiveness reality.

Natural family planning (NFP)

Luh-Hardegg G, 1984 · Geburtshilfe Frauenheilkd

The author reviews and makes further recommendations for 3 points of the discussion in G. Freundl's pilot study of "Natural Family Planning (Symptothermal Method) and Objective Ovulation Indicators" published by Georg Thieme Verlag in Vlume 6, "Geburtshilfe und Frauenheilkunde," in 1984. It is suggested that the scientific basis of changes in methodological rules, such as the BT3 modified for the double control method in paragraph 3 of the discussion, must be reported Natural Family Planning (NFP) instructors in Bonn, West Germany, along with failure statistics whenever possible, to enable instructors to participate responsibly. In response to errors by users cited in paragraph 4 of the discussion, the reviewer asserts that adequate instructional materials (photos and slides) are available to acquaint the users with changes in cervical mucus and that personal guidance of a couple or small group should be carried out until detection of fertility signals is performed without difficulty and the couple has proved itself capable of abstaining for the required periods, the latter being the more difficult. The author further cautions that before shortening of the abstinence period can be promoted, instructors must be scientifically assured of the accuracy of the basal temperature -6 indicator. She emphasizes that user errors can be reduced with a shorter abstinence period, but that the couple demands reliable rules first and foremost. The author concludes with a call for closer cooperation between gynecologists and NFP instructors.