To determine variability in the phases of the menstrual cycle among healthy, regularly cycling women.
Design
A prospective descriptive study of a new data set with biological markers to estimate parameters of the menstrual cycles.
Participants
One hundred forty one healthy women (mean age 29 years) who monitored 3 to 13 menstrual cycles with an electronic fertility monitor and produced 1,060 usable cycles of data. MEASURES AND
Outcomes
Variability in the length of the menstrual cycle and of the follicular, fertile, and luteal phases, and menses. The estimated day of ovulation and end of the fertile phase was the peak fertility reading on the monitor (i.e., the urinary luteinizing hormone surge).
Results
Mean total length was 28.9 days (SD = 3.4) with 95% of the cycles between 22 and 36 days. Intracycle variability of greater than 7 days was observed in 42.5% of the women. Ninety-five percent of the cycles had all 6 days of fertile phase between days 4 and 23, but only 25% of participants had all days of the fertile phase between days 10 and 17.
Conclusions
Among regularly cycling women, there is considerable normal variability in the phases of the menstrual cycle. The follicular phase contributes most to this variability.
PMID 16700687 16700687 DOI 10.1111/j.1552-6909.2006.00051.x 10.1111/j.1552-6909.2006.00051.x
Cite this article
Fehring, R. J., Schneider, M., & Raviele, K. (2006). Variability in the phases of the menstrual cycle. Journal of obstetric, gynecologic, and neonatal nursing : JOGNN, 35(3), 376-384. https://doi.org/10.1111/j.1552-6909.2006.00051.x
Fehring RJ, Schneider M, Raviele K. Variability in the phases of the menstrual cycle. J Obstet Gynecol Neonatal Nurs. 2006;35(3):376-384. doi:10.1111/j.1552-6909.2006.00051.x
Fehring, R. J., et al. "Variability in the phases of the menstrual cycle." Journal of obstetric, gynecologic, and neonatal nursing : JOGNN, vol. 35, no. 3, 2006, pp. 376-384.
Fehring RJ et al., 2017·J Obstet Gynecol Neonatal Nurs
To analyze the effectiveness of an online, nurse-managed natural family planning (NFP) program among breastfeeding women and subgroups of these women.
Longitudinal comparative cohort study.
A university-based online NFP education program and menstrual cycle charting system. Women (N = 816) with a mean age of 30.3 years (standard deviation = 4.5) who registered to use the online NFP system and indicated they were breastfeeding. Participants tracked their fertile times with an electronic hormone fertility monitor (EHFM), cervical mucus monitoring, or both. All unintended pregnancies were evaluated by professional nurses. The correct use pregnancy rates were 3 per 100 users over 12 cycles of use, and typical rates were 14 per 100 at 12 cycles of use. At 12 cycles of use, total pregnancy rates were 16 per 100 for electronic hormone fertility monitor users (n = 380), 81 per 100 among mucus-only users (n = 45), and 14 per 100 for electronic hormone fertility monitor plus mucus users (n = 391). Use of a nurse-managed online NFP program for women can be effective to help women avoid pregnancy while breastfeeding, especially with correct and consistent use.
Fertility AwarenessPerimenopause UseNatural Family PlanningSurvival Analysis
Fehring RJ et al., 2014·J Obstet Gynecol Neonatal Nurs
To determine the efficacy of using natural family planning (NFP) methods to avoid unintended pregnancy among women of perimenopause age (i.e., age 40-55 years).
A secondary analysis of subset data from two prospective observational cohort studies.
A university based in-person and online NFP service program. One hundred and sixty couples who used either a website or an in-person NFP service to learn how to avoid pregnancy from January 2001 to November 2012. A prospective 12-month effectiveness study among 160 women (between ages 40-55) who used NFP to avoid pregnancy. The women used either a hormonal fertility monitor, cervical mucus monitoring, or both to estimate the fertile phase of their menstrual cycles. Survival analysis was used to determine the pregnancy rate over 12 months of use. There were a total of five unintended pregnancies among the participants. The typical use pregnancy rate was six per 100 women over 12 months. The monitor alone participants (n = 35) had a 12-month pregnancy rate of three, the participants (n = 73) who used mucus alone had a pregnancy rate of four, and the participants (n = 42) who used the fertility monitor plus mucus had a pregnancy rate of six. Natural family planning methods can be effective for older women to avoid an unintended pregnancy with correct use and adequate instructions. The pregnancy rate most likely was affected by diminished fertility and motivation to limit family size.
Fehring RJ et al., 2011·J Obstet Gynecol Neonatal Nurs
To evaluate the efficacy, knowledge of fertility, and acceptability of a web-based natural family planning (NFP) education and service program.
A 6-month repeated measure longitudinal evaluation pilot study.
A university based online website. The website was piloted with 468 volunteer women seeking NFP services. Of these participants, 222 used the automatic online fertility charting system to avoid pregnancy. The 222 charting participants had a mean age of 29.9 years (SD=5.6), 2.2 children (SD=1.9), 37% were postpartum, and 47% had regular menstrual cycle lengths. Nurse-managed web-based NFP education and service program. Pregnancies were confirmed by an online self-assessed pregnancy evaluation form. A 10-item fertility quiz and 10-item acceptability survey was administered online. Among the 222 users avoiding pregnancy, at 6 months of use, there were two correct-use unintended pregnancies that provided a pregnancy rate of 2% and seven total unintended pregnancies providing a typical use pregnancy rate of 7%. Mean knowledge of fertility increased significantly from time of registration (8.96, SD=1.10) to 1 month of use (9.46, SD=.10), t=4.60, p<.001). Acceptability increased nonsignificantly from 1 month of use (45.6; SD=8.98) to 6 months of use (48.4; SD=8.77). The nurse-managed online NFP system seems to provide adequate knowledge of fertility and help participants meet pregnancy intentions. Acceptability of such a system of NFP is still in question.
Fertility AwarenessElectronic Hormonal MonitoringCorrect and Typical Use RatesCervical Mucus Monitoring
Fehring RJ et al., 2007·J Obstet Gynecol Neonatal Nurs
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.