Physicians who counsel women for preconception concerns are in an excellent position to give advice to couples regarding the optimal timing of intercourse to achieve pregnancy. The currently available evidence suggests that methods that prospectively identify the window of fertility are likely to be more effective for optimally timing intercourse than calendar calculations or basal body temperature. There are several promising methods with good scientific bases to identify the fertile window prospectively. These include fertility charting of vaginal discharge and a commercially available fertility monitor. These methods identify the occurrence of ovulation clinically and also identify a longer window of fertility than urinary luteinizing hormone kits. Prospectively identifying the full window of fertility may lead to higher rates of conception. Proper information given early in the course of trying to achieve pregnancy is likely to reduce time to conception for many couples, and also to reduce unnecessary intervention and cost.
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PMID 12468181 12468181 DOI 10.1016/s0029-7844(02)02382-7 10.1016/s0029-7844(02)02382-7 Stanford et al. 2002, Stanford 2002
Cite this article
Stanford, J. B., White, G. L., & Hatasaka, H. (2002). Timing intercourse to achieve pregnancy: current evidence. Obstetrics and gynecology, 100(6), 1333-1341. https://doi.org/10.1016/s0029-7844(02)02382-7
Stanford JB, White GL, Hatasaka H. Timing intercourse to achieve pregnancy: current evidence. Obstet Gynecol. 2002;100(6):1333-1341. doi:10.1016/s0029-7844(02)02382-7
Stanford, J. B., et al. "Timing intercourse to achieve pregnancy: current evidence." Obstetrics and gynecology, vol. 100, no. 6, 2002, pp. 1333-1341.
Keywords
Adult, Body Temperature, Coitus, Family Planning Services/methods, Female, Humans, Male, Menstrual Cycle/physiology, Natural Family Planning Methods, Ovulation Detection/methods, Pregnancy, Pregnancy Rate, Sensitivity and Specificity, Time Factors
The estimated time of ovulation (ETO) was correlated with the day of defined postovulatory infertility in 66 hormonally normal menstrual cycles from 24 subjects for each of 15 different natural family planning methodologies. Inherent weaknesses were identified in methods based upon calendar calculations or basal body temperature only. These weaknesses could be removed for the basal body temperature-only methods if symptoms, especially the peak mucus symptom, were added to the temperature records. However, the peak mucus symptom alone had the greatest precision of all methods studied. No advantage could be identified in combining the basal body temperature with the peak symptom.
Porucznik CA et al., 2014·BMC Womens Health·
Open Access
Transient exposures may influence fertility and early embryonic development. To assess the time of conception in vivo and conduct concurrent biomonitoring, ovulation must be identified prospectively. We report on the development and validation of a simple, prospective method, the Peak Day method, to determine likely day of ovulation based upon daily observations of cervical fluid. We recruited 98 women to learn the Peak Day method from a brochure, 26 of whom concurrently used the method with blinded daily urine hormone monitoring (estrone glucuronide and luteinizing hormone). All women were instructed to complete an exposure questionnaire immediately upon identifying ovulation. Briefly, the exposure questionnaire captured time-varying and transient exposures such as medication use, water consumption, and amount of sleep. We assessed timely completion of the exposure questionnaire, agreement of women's estimated day of ovulation (EDO) and the EDO by expert review, and agreement between the EDO by expert review and by blinded urine monitoring. Of 147 cycles evaluated, women selected an EDO in 130 (88%) and subsequently completed the periovulatory exposure questionnaire in 122 (94%) cycles. Of the 26 cycles evaluated with blinded hormonal monitoring, the Peak Day "best quality" algorithm, based upon cervical fluid, identified ovulation ± 3 days of the urine monitor in 24 cycles (92%). With simple written instructions, women can identify an estimated day of ovulation and perform periovulatory exposure assessment. The Peak Day method is highly cost-effective and could be applied by researchers to target periconceptional or very early developmental stage exposure assessment.
Dynamic latent class models provide a flexible framework for studying biologic processes that evolve over time. Motivated by studies of markers of the fertile days of the menstrual cycle, we propose a discrete-time dynamic latent class framework, allowing change points to depend on time, fixed predictors, and random effects. Observed data consist of multivariate categorical indicators, which change dynamically in a flexible manner according to latent class status. Given the flexibility of the framework, which incorporates semi-parametric components using mixtures of betas, identifiability constraints are needed to define the latent classes. Such constraints are most appropriately based on the known biology of the process. The Bayesian method is developed particularly for analyzing mucus symptom data from a study of women using natural family planning.
Fehring RJ et al., 2004·Contraception·
Open Access
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.