Stanford, J. B., Willis, S. K., Hatch, E. E., Rothman, K. J., & Wise, L. A. (2019). Fecundability in relation to use of fertility awareness indicators in a North American preconception cohort study. Fertility and Sterility, 112(5), 892-899. https://doi.org/10.1016/j.fertnstert.2019.06.036
Stanford JB, Willis SK, Hatch EE, Rothman KJ, Wise LA. Fecundability in relation to use of fertility awareness indicators in a North American preconception cohort study. Fertil Steril. 2019;112(5):892-899. doi:10.1016/j.fertnstert.2019.06.036
Stanford, Joseph Barney, et al. "Fecundability in relation to use of fertility awareness indicators in a North American preconception cohort study." Fertility and Sterility, vol. 112, no. 5, 2019, pp. 892-899.
Slone Epidemiology Center at Boston University, Boston, Massachusetts and 2Lombardi Comprehensive Cancer Center at Georgetown University Medical Center, Washington, District of Columbia05vzafd60
Linked to ROR, the Research Organization Registry
RRM Academy Synopsis
Fertility indicator use linked to faster pregnancy in 5,688 women
Women who used fertility indicators had a higher monthly chance of pregnancy in this cohort. The web-based study followed 5,688 North American women who had tried to conceive for six cycles or fewer. The highest ratio came from charting days, watching cervical fluid, and using urine LH tests together.
Key Findings
The analysis included 5,688 women aged 21 to 45 who had tried to conceive for six cycles or fewer. At baseline, 75% used at least one fertility indicator.
Any indicator use at baseline went with an adjusted fecundability ratio of 1.25 (95% CI 1.16–1.35) against no use. The time-varying analysis gave 1.31 (95% CI 1.21–1.42).
In the time-varying analysis, adjusted ratios for each single indicator ranged from 1.28 to 1.36, where 1.00 means no relation with fecundability.
Charting days, cervical fluid, and urine LH together gave an adjusted ratio of 1.48 (95% CI 1.31–1.67) in the time-varying analysis.
Adjusted ratios were 1.31 to 1.43 in women trying for fewer than 3 cycles at entry, and 1.07 to 1.10 in women trying for 3 to 6 cycles.
Interpretation
The Pregnancy Study Online is an observational cohort, so the ratios show an association. The authors write that residual confounding may explain some or all of it, since charting can mark couples who try harder. The questionnaire recorded no timing of intercourse, and women reported their own indicator use. Most participants were married (91%) and college educated (74%). The authors say results may not apply to women with less education.
RRM Context
Fertility awareness methods teach couples to observe the fertile window through signs such as cervical fluid. Restorative reproductive medicine builds on that cycle-charting-informed approach. The authors cite earlier cohorts with positive associations and say randomized trials gave mixed results. A chart also gives an RRM clinician cycle information to read when asking why pregnancy has not happened.
Our editorial summary of this paper, not the article's abstract.
Abstract
Objective
To quantify the frequency of use of selected fertility awareness indicators and to assess their influence on fecundability.
Design
Web-based prospective cohort study.
Setting
Not applicable.
Patients
Female pregnancy planners, aged 21-45 years, attempting conception for ≤6 cycles at study entry.
Interventions
None.
Main Outcome Measures
We ascertained time to pregnancy, in menstrual cycles, with bimonthly questionnaires. We estimated adjusted fecundability ratios (FRs) and confidence intervals (CIs) using proportional probabilities models, controlling for age, income, education, smoking, intercourse frequency, and other lifestyle and reproductive factors.
Results
A total of 5,688 women were analyzed, with a mean age of 29.9 years and mean time trying of 2.1 cycles at baseline; 30% had ever been pregnant. At baseline, 75% were using one or more fertility indicators (counting days or charting menstrual cycles [71%], measuring basal body temperature [BBT, 21%], monitoring cervical fluid [39%], using urine LH tests [32%], or feeling for changes in position of the cervix [12%]). Women using any fertility indicator at baseline had higher subsequent fecundability (adjusted FR 1.25, 95% CI 1.16-1.35) than those not using any fertility indicators. For each individual indicator, adjusted FRs ranged from 1.28-1.36, where 1.00 would indicate no relation with fecundability. The adjusted FR for women using a combination of charting days, cervical fluid, and urine LH was 1.48 (95% CI 1.31-1.67) relative to women using no fertility indicators.
Conclusions
In a North American preconception cohort study, use of fertility indicators indicating the fertile window was common, and was associated with greater fecundability.
05qwgg493 