In order to evaluate the relationship between the urinary luteinizing hormone (LH) surge as detected by the OvuSTICK (Monoclonal Antibodies, Inc., Mountain View, CA) method and daily cervical mucus parameters, ten spontaneously ovulating women undergoing infertility evaluation were followed during their cycles with twice daily urinary LH testing as well as daily ultrasound, mucus evaluation, and hormonal assays of serum LH, progesterone (P), and estradiol (E2). Maximal cervical mucus scores, as determined using a modified Insler score, were noted to coincide consistently with the urinary LH surge as detected by twice daily testing and to precede ultrasound evidence of ovulation by 0 to 24 hours. Mucus scores rapidly declined in the 24-hour period following the urinary LH surge. Detection of the urinary LH surge may therefore help identify that period of time during which cervical mucus parameters are optimal and therefore facilitate the timing of artificial insemination, intercourse, or postcoital testing.
PMID 3311823 3311823 DOI 10.1016/s0015-0282(16)59530-2 10.1016/s0015-0282(16)59530-2 Nulsen et al. 1987, Nulsen 1987
Cite this article
Nulsen, J., Wheeler, C., Ausmanas, M., & Blasco, L. (1987). Cervical mucus changes in relationship to urinary luteinizing hormone. Fertility and Sterility, 48(5), 783-786. https://doi.org/10.1016/s0015-0282(16)59530-2
Nulsen J, Wheeler C, Ausmanas M, Blasco L. Cervical mucus changes in relationship to urinary luteinizing hormone. Fertil Steril. 1987;48(5):783-786. doi:10.1016/s0015-0282(16)59530-2
Nulsen, J., et al. "Cervical mucus changes in relationship to urinary luteinizing hormone." Fertility and sterility, vol. 48, no. 5, 1987, pp. 783-786.
What is the normal range of cervical mucus patterns and number of days with high or moderate day-specific probability of pregnancy (if intercourse occurs on a specific day) based on cervical mucus secretion, in women without known subfertility, and how are these patterns related to parity and age? The mean days of peak type (estrogenic) mucus per cycle was 6.4, the mean number of potentially fertile days was 12.1; parous versus nulliparous, and younger nulliparous (<30 years) versus older nulliparous women had more days of peak type mucus, and more potentially fertile days in each cycle. The rise in estrogen prior to ovulation supports the secretion of increasing quantity and estrogenic quality of cervical mucus, and the subsequent rise in progesterone after ovulation causes an abrupt decrease in mucus secretion. Cervical mucus secretion on each day correlates highly with the probability of pregnancy if intercourse occurs on that day, and overall cervical mucus quality for the cycle correlates with cycle fecundability. No prior studies have described parity and age jointly in relation to cervical mucus patterns. STUDY DESIGN, SIZE, This study is a secondary data analysis, combining data from three cohorts of women: 'Creighton Model MultiCenter Fecundability Study' (CMFS: retrospective cohort, 1990-1996), 'Time to Pregnancy in Normal Fertility' (TTP: randomized trial, 2003-2006), and 'Creighton Model Effectiveness, Intentions, and Behaviors Assessment' (CEIBA: prospective cohort, 2009-2013). We evaluated cervical mucus patterns and estimated fertile window in 2488 ovulatory cycles of 528 women, followed for up to 1 year. PARTICIPANTS/MATERIALS, SETTING, Participants were US or Canadian women age 18-40 years, not pregnant, and without any known subfertility. Women were trained to use a standardized protocol (the Creighton Model) for daily vulvar observation, description, and recording of cervical mucus. The mucus peak day (the last day of estrogenic quality mucus) was used as the estimated day of ovulation. We conducted dichotomous stratified analyses for cervical mucus patterns by age, parity, race, recent oral contraceptive use (within 60 days), partial breast feeding, alcohol, and smoking. Focusing on the clinical characteristics most correlated to cervical mucus patterns, linear mixed models were used to assess continuous cervical mucus parameters and generalized linear models using Poisson regression with robust variance were used to assess dichotomous outcomes, stratifying by women's parity and age, while adjusting for recent oral contraceptive use and breast feeding. MAIN The majority of women were <30 years of age (75.4%) (median 27; IQR 24-29), non-Hispanic white (88.1%), with high socioeconomic indicators, and nulliparous (70.8%). The mean (SD) days of estrogenic (peak type) mucus per cycle (a conservative indicator of the fertile window) was 6.4 (4.2) days (median 6; IQR 4-8). The mean (SD) number of any potentially fertile days (a broader clinical indicator of the fertile window) was 12.1 (5.4) days (median 11; IQR 9-14). Taking into account recent oral contraceptive use and breastfeeding, nulliparous women age ≥30 years compared to nulliparous women age <30 years had fewer mean days of peak type mucus per cycle (5.3 versus 6.4 days, P = 0.02), and fewer potentially fertile days (11.8 versus 13.9 days, P < 0.01). Compared to nulliparous women age <30 years, the likelihood of cycles with peak type mucus ≤2 days, potentially fertile days ≤9, and cervical mucus cycle score (for estrogenic quality of mucus) ≤5.0 were significantly higher among nulliparous women age ≥30 years, 1.90 (95% confidence interval (CI) 1.18, 3.06); 1.46 (95% CI 1.12, 1.91); and 1.45 (95% CI 1.03, 2.05), respectively. Between parous women, there was little difference in mucus parameters by age. Thresholds set a priori for within-woman variability of cervical mucus parameters by cycle were examined as follows: most minus fewest days of peak type mucus >3 days (exceeded by 72% of women), most minus fewest days of non-peak type mucus >4 days (exceeded by 54% of women), greatest minus least cervical mucus cycle score >4.0 (exceeded by 73% of women), and most minus fewest potentially fertile days >8 days (found in 50% of women). Race did not have any association with cervical mucus parameters. Recent oral contraceptive use was associated with reduced cervical mucus cycle score and partial breast feeding was associated with a higher number of days of mucus (both peak type and non-peak type), consistent with prior research. Among the women for whom data were available (CEIBA and TTP), alcohol and tobacco use had minimal impact on cervical mucus parameters. LIMITATIONS, We did not have data on some factors that may impact ovulation, hormone levels, and mucus secretion, such as physical activity and body mass index. We cannot exclude the possibility that some women had unknown subfertility or undiagnosed gynecologic disorders. Only 27 women were age 35 or older. Our study participants were geographically dispersed but relatively homogeneous with regard to race, ethnicity, income, and educational level, which may limit the generalizability of the findings. Patterns of cervical mucus secretion observed by women are an indicator of fecundity and the fertile window that are consistent with the known associations of age and parity with fecundity. The number of potentially fertile days (12 days) is likely greater than commonly assumed, while the number of days of highly estrogenic mucus (and higher probability of pregnancy) correlates with prior identifications of the fertile window (6 days). There may be substantial variability in fecundability between cycles for the same woman. Future work can use cervical mucus secretion as an indicator of fecundity and should investigate the distribution of similar cycle parameters in women with various reproductive or gynecologic pathologies. STUDY FUNDING/COMPETING INTEREST(S): Funding for the three cohorts analyzed was provided by the Robert Wood Johnson Foundation (CMFS), the Eunice Kennedy Shriver National Institute of Child Health and Human Development (TTP), and the Office of Family Planning, Office of Population Affairs, Health and Human Services (CEIBA). The authors declare that they have no conflict of interest. N/A.
Hilgers TW, 2004·The Medical and Surgical Practice of NaProTECHNOLOGY
The CREIGHTON MODEL FertilityCare System (CrMS) rests on a decades-long body of research demonstrating that cervical mucus functions as a physiologically regulated biological valve, opening predictably at the periovulatory estrogen rise and closing in the post-Peak phase. Chapter 15 of Hilgers (2004) synthesizes hormonal, ultrasound, cytologic, and biophysical evidence to establish that a woman's external observation of her Peak Day reliably identifies the fertile window, and documents the system's effectiveness data for both achieving and avoiding pregnancy across a five-study meta-analysis of nearly 1,900 couples.
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.
12 normal ovulatory women were studied during 17 menstrual cycles. The first day on which the women had increasing quantities of 0.1 ml or more clear cervical mucus (IQCCM) was closely related to the time of ovulation as monitored by basal body temperature and radioimmunoassay of serum-luteinizing hormone, follicle-stimulating hormone, estradiol, and progesterone. The results show that the time of ovulation can be predicted clinically without specialized tests by observing the day of onset of IQCCM.