Fehring, R. J., & Gaska, N. (1998). Evaluation of the Lady Free Biotester in determining the fertile period. Contraception, 57(5), 325-328. https://doi.org/10.1016/s0010-7824(98)00039-0
Fehring RJ, Gaska N. Evaluation of the Lady Free Biotester in determining the fertile period. Contraception. 1998;57(5):325-328. doi:10.1016/s0010-7824(98)00039-0
Fehring, R. J., and N. Gaska. "Evaluation of the Lady Free Biotester in determining the fertile period." Contraception, vol. 57, no. 5, 1998, pp. 325-328.
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Saliva ferning peaks tracked the LH surge in a 12-woman study
In a 1998 study of 12 natural family planning teachers, the peak day of saliva ferning on a pocket microscope tracked the urinary LH surge day closely (r = 0.98). Twenty-four cycles gave usable data. In this study, ferning gave no clear start or end to the fertile time.
Key Findings
Twenty-four cycles gave usable data. The peak day of AM and PM salivary ferning each correlated with the day of the LH surge (r = 0.98, p ≤ 0.001).
Peak cervical-vaginal mucus ferning and the Creighton Model peak day of cervical mucus each correlated with the LH surge day (r = 0.99, p ≤ 0.001).
Full ferning appeared in 11 of 20 cycles (55%) for cervical-vaginal mucus, 12 of 20 (60%) for PM saliva, and 9 of 21 (43%) for AM saliva.
The authors found no discernible beginning or end of fertility from salivary or cervical-vaginal ferning. Ferning days ran through some cycles and fell on only 1 or 2 days in others.
One participant's saliva on a regular glass slide showed ferning every day of a cycle. One investigator's own saliva showed the top ferning level.
Interpretation
The study is a small evaluation of 12 experienced volunteers over two cycles each, compared with a urinary LH test and mucus charting. The device was checked against those two markers only. The correlations describe the day of the ferning peak, read alongside the other markers. The authors see some question about the theory behind salivary ferning, since ferning also appears in male saliva and across the female cycle. The authors suggest that saliva collection and microscope quality may have shaped some results. The authors advise that hand-held microscopes stay out of pregnancy avoidance until better tests exist.
RRM Context
The Creighton Model mucus observations served as one reference in this study, and the mucus peak correlated closely with the LH surge day, as the saliva readings did. RRM methods teach women to read fertility signs they can see each day. This paper tests one device against those signs, and the authors place it only beside other tested markers.
Our editorial summary of this paper, not the article's abstract.
Abstract
Small hand-held microscopes have been developed for self-observation of salivary ferning patterns to detect the fertile time of a woman's menstrual cycle. The purpose of this study was to evaluate one such microscope, the Lady Free Biotester, by comparing it with the self-observation of cervical-vaginal mucus and with the self-detection of luteinizing hormone (LH) in the urine. Twelve natural family planning teachers (average age 34.6 years) observed their cervical-vaginal mucus, tested their urine for LH, and observed salivary and cervical-vaginal mucus ferning patterns (with the Lady Free Biotester) for two menstrual cycles. Data indicated that there was a strong correlation between the LH in the urine and the peak in self-observed cervical-vaginal mucus ferning (r = 0.99, p < or = 0.001) and salivary ferning (r = 0.98, p < or = 0.001). However, it was difficult to assess the beginning and end of the fertile time based on the salivary ferning patterns. Further testing of salivary ferning patterns is recommended before widespread use of these devices for family planning.
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.
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.
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.
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.
Fehring RJ et al., 2004·Contraception·Free to read
The purpose of this study was to compare the fertile phase of the menstrual cycle as determined by the Clearplan Easy Fertility Monitor (CPEFM) with self-monitoring of cervical mucus. One-hundred women (mean age = 29.4 years) observed their cervical mucus and monitored their urine for estrogen and luteinizing hormone metabolites with the CPEFM on a daily basis for 2-6 cycles and generated 378 cycles of data; of these, 347 (92%) had a CPEFM peak. The beginning of the fertile window was, on average, day 11.8 (SD = 3.4) by the monitor and day 9.9 (SD = 3.0) by cervical mucus (r = 0.43, p < 0.001). The average first day of peak fertility by the monitor was 16.5 (SD = 3.6) and by cervical mucus 16.3 (SD = 3.7) (r = 0.85, p < 0.001). The mean length of the fertile phase by the monitor was 7.7 days (SD = 3.1) and by cervical mucus 10.9 days (SD = 3.7) (t = 12.7, p < 0.001). The peak in fertility as determined by the monitor and by self-assessment of cervical mucus is similar but the monitor tends to underestimate and self-assessment of cervical mucus tends to overestimate the actual fertile phase.
Fehring RJ et al., 2007·J Obstet Gynecol Neonatal Nurs·Free to read
To determine the effectiveness of an electronic hormonal fertility monitor plus cervical mucus monitoring to avoid pregnancy.
A 12-month prospective clinical efficacy trial. One hundred ninety five (195) women (mean age 29.8 years) seeking to avoid pregnancy with a natural method at 5 clinical sites in 4 cities. Each participant was taught to track fertility by self-observation of cervical mucus and an electronic monitor that measures urinary levels of estrone-3-glucuronide and luteinizing hormone. Correctand typical-use unintended pregnancy rates. There were a total of 26 unintended pregnancies, 3 with correct use. With 1,795 months of use, the correct-use pregnancy rate was 2.1% per 12 months of use (i.e., 97.9% effective in avoiding pregnancy when rules of the method were always followed) and the imperfect-use pregnancy rate was 14.2% per 12 months of use (i.e., 85.8% effective in avoiding pregnancy when rules of the method were not always followed and all unintended pregnancies and months of use were included in the calculations). Correct use of an electronic hormonal fertility monitor with cervical mucus observations can be as effective as other fertility awareness-based methods of natural family planning. Comparative studies are needed to confirm this conclusion.
The first study was done in which vaginal hormonal cytograms were correlated with cervical mucus symptoms as charted by women using the ovulation method of natural family planning. Daily vaginal smears obtained by 67 women during 78 menstrual cycles provided the basis of the study. The women had used the ovulation method for at least three cycles and were not breast-feeding. All vaginal smears examined cytologically had a microbiologic diagnosis of lactobacilli. All the vaginal hormonal cytograms revealed ovulatory-type patterns. Karyopyknotic index (KPI) peak correlated with peak mucus day +/-2 days in 74, or 94.9%, of the cases, with a mean of peak mucus at +0.14 days. The average number of mucus days prior to the KPI peak was 6.1. Seven women also provided daily blood specimens for bioassay of luteinizing hormone (LH). KPI peaked with a mean of 0.7 days after the LH peak.
It is now well accepted that a woman can conceive from an act of intercourse for a maximum of only about 7 days of her menstrual cycle. The reliability of natural family planning depends on identifying this window of fertility without ambiguity. Several symptomatic markers, cervical mucus and basal body temperature, have been used extensively and with considerable success in most women but failures occur. Ovarian and pituitary hormone production show characteristic patterns during the cycle. Urinary estrogen and pregnanediol measurements yield reliable information concerning the beginning, peak, and end of the fertile period, provided that the assays are accurate and performed on timed specimens of urine. We have developed such enzyme immunoassays for urinary estrogen and pregnanediol glucuronides that can be performed at home. In the early versions of the assays, enzyme reaction rates were measured by eye, but more recently, a simple photoelectronic rate meter has been used. The final problem to be solved is not technologic but whether women are sufficiently motivated to expend the same time and effort each day for 10 days a month, with less cost, on fertility awareness as they spend on making a cup of tea.
Rick Fehring, Dick Fehring, Rich Fehring, R Fehring
PMID 9673839 9673839 DOI 10.1016/s0010-7824(98)00039-0 10.1016/s0010-7824(98)00039-0 Fehring et al. 1998, Fehring 1998
Cite this article
Fehring, R. J., & Gaska, N. (1998). Evaluation of the Lady Free Biotester in determining the fertile period. Contraception, 57(5), 325-328. https://doi.org/10.1016/s0010-7824(98)00039-0
Fehring RJ, Gaska N. Evaluation of the Lady Free Biotester in determining the fertile period. Contraception. 1998;57(5):325-328. doi:10.1016/s0010-7824(98)00039-0
Fehring, R. J., and N. Gaska. "Evaluation of the Lady Free Biotester in determining the fertile period." Contraception, vol. 57, no. 5, 1998, pp. 325-328.
Keywords
Adult, Cervix Mucus/chemistry, Crystallization, Family Planning Services, Female, Humans, Luteinizing Hormone/urine, Menstrual Cycle, Ovulation Detection/instrumentation, Saliva/chemistry, Luteinizing Hormone, Americas, Clinical Research, Developed Countries, Equipment And Supplies, Examinations And Diagnoses, Family Planning, Family Planning, Behavioral Methods, Fertile Period, Laboratory Examinations And Diagnoses, Laboratory Procedures, Natural Family Planning, North America, Northern America, Ovulation Detection, Reproduction, Research Methodology, Research Report, United States
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