Intercourse results in a pregnancy essentially only if it occurs during the 6-day fertile interval ending on the day of ovulation. The strong association between timing of intercourse within this interval and the probability of conception typically is attributed to limited sperm and egg life times.
Methods
A total of 782 women recruited from natural family planning centres in Europe contributed prospective data on 7288 menstrual cycles. Daily records of intercourse, basal body temperature and vaginal discharge of cervical mucus were collected. Probabilities of conception were estimated according to the timing of intercourse relative to ovulation and a 1-4 score of mucus quality.
Results
There was a strong increasing trend in the day-specific probabilities of pregnancy with increases in the mucus score. Adjusting for the mucus score, the day-specific probabilities had limited variability across the fertile interval.
Conclusions
Changes in mucus quality across the fertile interval predict the observed pattern in the day-specific probabilities of conception. To maximize the likelihood of conception, intercourse should occur on days with optimal mucus quality, as observed in vaginal discharge, regardless of the exact timing relative to ovulation.
PMID 14990542 14990542 DOI 10.1093/humrep/deh173 10.1093/humrep/deh173
Cite this article
Bigelow, J. L., Dunson, D. B., Stanford, J. B., Ecochard, R., Gnoth, C., & Colombo, B. (2004). Mucus observations in the fertile window: a better predictor of conception than timing of intercourse. Human reproduction (Oxford, England), 19(4), 889-892. https://doi.org/10.1093/humrep/deh173
Bigelow JL, Dunson DB, Stanford JB, Ecochard R, Gnoth C, Colombo B. Mucus observations in the fertile window: a better predictor of conception than timing of intercourse. Hum Reprod. 2004;19(4):889-892. doi:10.1093/humrep/deh173
Bigelow, J. L., et al. "Mucus observations in the fertile window: a better predictor of conception than timing of intercourse." Human reproduction (Oxford, England), vol. 19, no. 4, 2004, pp. 889-892.
Keywords
Adult, Cervix Mucus/physiology, Cohort Studies, Coitus, Europe, Female, Fertility/physiology, Fertilization, Humans, Medical Records, Natural Family Planning Methods/standards, Pregnancy, Probability, Prospective Studies, Time Factors
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.
Are dietary patterns associated with age at menarche after accounting for BMI-for-age (BMIz) and height? We observed associations between both the Alternative Healthy Eating Index (AHEI) and the Empirical Dietary Inflammatory Pattern (EDIP) and age at menarche. Dietary patterns have been sparsely examined in relation to age at menarche and no studies have examined the association between the AHEI, a healthier diet, and EDIP, a pro-inflammatory diet, and menarche. STUDY DESIGN, SIZE, The Growing Up Today Study (GUTS) is a prospective cohort of children ages 9-14 years at study enrollment. GUTS enrolled in two waves with enrollment beginning in 1996 (GUTS1) and 2004 (GUTS2). For this analysis, GUTS1 and GUTS2 participants were followed through 2001 and 2008, respectively. PARTICIPANTS/MATERIALS, SETTING, We included 7530 participants who completed food frequency questionnaire(s) (FFQ) prior to menarche who then self-reported age at menarche during study follow-up. Cox proportional hazard models were used to calculate multivariable hazard ratios (HRs) and 95% CIs for the associations between two dietary patterns, the AHEI and EDIP, and age at menarche, with and without adjustment for time-varying BMIz and height. MAIN Six thousand nine hundred ninety-two participants (93%) reported menarche during the study period. On average, participants completed the baseline FFQ 1.75 years prior to menarche. Participants in the highest quintile of AHEI diet score (indicating a healthier diet) were 8% less likely to attain menarche within the next month compared to those in the lowest quintile (95% CI = 0.85-0.99; Ptrend = 0.03). This association remained after adjustment for BMIz and height (corresponding HR = 0.93; 95% CI = 0.86-1.00; Ptrend = 0.04). Participants in the highest quintile of the EDIP score (i.e. most inflammatory diet), were 15% more likely to attain menarche in the next month relative to those in the lowest quintile (95% CI = 1.06-1.25; Ptrend = 0.0004), and the association remained following adjustment for BMIz and height (corresponding HR = 1.15; 95% CI = 1.06-1.25; Ptrend = 0.0004). LIMITATIONS, Self-reported questionnaires are subject to some error; however, given our prospective study design it is likely this error is non-differential with respect to the outcome. Our findings of an association between both the AHEI and EDIP and age at menarche indicate that diet quality may play a role in age at menarche independent of BMI or height. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Breast Cancer Research Foundation. The GUTS is supported by the National Institutes of Health U01 HL145386. C.P.D. was supported by National Institutes of Health T32 CA094880. The authors have no conflicts of interest to disclose. N/A.
EndometriosisMenopause TimingEndometriosis HistoryPooled Cohort Analysis
Open Access
What is the association between endometriosis and the type and age of menopause? Women with endometriosis had a 7-fold increased risk of undergoing surgical menopause rather than natural menopause and were more likely to experience premature or early menopause, both surgically and naturally. Endometriosis is associated with reduced ovarian reserve, but evidence on its relationship with the type of menopause (surgical vs natural) and timing (especially premature and early menopause) is limited. Women with endometriosis are more likely to undergo hysterectomy and/or oophorectomy (either unilateral or bilateral), but the average age of these surgeries remains unclear. STUDY DESIGN, SIZE, The study analysed individual-level data from 279 948 women in five cohort studies conducted in the UK, Australia, Sweden, and Japan between 1996 and 2022. PARTICIPANTS/MATERIALS, SETTING, Women whose menopause type and age could not be determined due to premenopausal hysterectomy with ovarian preservation or use of menopausal hormone therapy were excluded. Endometriosis was identified through self-reports and administrative data. Surgical menopause was defined as premenopausal bilateral oophorectomy. Fine-Gray subdistribution hazard models estimated hazard ratios (HRs) for surgical and natural menopause. Age at menopause was determined by the ages at the final menstrual period or bilateral oophorectomy. Linear regression assessed mean differences in menopause age, while multinomial logistic regression estimated odds ratios (ORs) <40 (premature), 40-44 (early), 45-49, 50-51 (reference), 52-54, and ≥55 years. Spontaneous premature ovarian insufficiency (POI) was defined as natural menopause before age 40 years. MAIN Endometriosis was identified in 3.7% of women. By the end of follow-up, 7.9% had surgical menopause and 58.2% experienced natural menopause. Using a competing risk model, women with endometriosis had a 7-fold increased risk of surgical menopause (HR: 7.54, 95% CI 6.84, 8.32) and were less likely to experience natural menopause (HR: 0.40, 95% CI 0.33, 0.49). On average, surgical menopause occurred 1.6 years (19 months) earlier (β: -1.59, 95% CI -1.77, -1.42) in women with endometriosis. Among women who experienced natural menopause, it was 0.4 years (5 months) earlier (β: -0.37, 95% CI -0.46, -0.28) for those with endometriosis. Women with endometriosis were twice as likely to experience premature surgical menopause (<40 years) (OR: 2.11, 95% CI 2.02, 2.20) or 1.4 times more likely to develop spontaneous POI (OR: 1.36, 95% CI 1.17, 1.59). They were also at increased odds of early surgical and natural menopause (40-44 years). LIMITATIONS, This study could not differentiate between subtypes and stages of endometriosis or assess treatments for ovarian endometrioma, which may impact ovarian reserve. Self-reported menopause type and age could introduce recall bias. Given the consistent findings across individual studies, our results are likely to be generalizable to different populations, highlighting the need for tailored management of endometriosis to prevent medically induced or premature menopause. Long-term monitoring of women with endometriosis is recommended, given their elevated risk of surgical menopause and premature or early menopause, which are associated with adverse health outcomes in later life. STUDY FUNDING/COMPETING INTEREST(S): The InterLACE Consortium is funded by the Australian National Health and Medical Research Council project grant (APP1027196) and Centres of Research Excellence (APP1153420). G.D.M. is funded by the Australian National Health and Medical Research Council Leadership Fellowship (APP2009577). This research is funded in part by the Japan Society for the Promotion of Science (JSPS 19KK0235, 23KK0167). The authors have no conflict of interest. Where authors are identified as personnel of the International Agency for Research on Cancer or WHO, the authors alone are responsible for the views expressed in this article, and they do not necessarily represent the decisions, policy, or views of the International Agency for Research on Cancer or WHO. N/A.