The Oxford Conception Study design and recruitment experience

Timed intercourse for couples trying to conceive

BACKGROUND

Many factors influence fertility, one being the timing of intercourse. The 'fertile window' describes a stage in the cycle when conception can occur and is approximately five days before to several hours after ovulation. 'Timed intercourse' is the practice of prospectively identifying ovulation and, thus, the fertile window to increase the likelihood of conception. Methods of predicting ovulation include urinary hormone measurement (luteinising hormone (LH) and oestrogen), fertility awareness-based methods (FABM) (including tracking basal body temperatures, cervical mucus monitoring, calendar charting/tracking apps), and ultrasonography. However, there are potentially negative aspects associated with ovulation prediction, including stress, time consumption, and cost implications of purchasing ovulation kits and app subscriptions. This review considered the evidence from randomised controlled trials (RCTs) evaluating the use of timed intercourse (using ovulation prediction) on pregnancy outcomes.

OBJECTIVES

To evaluate the benefits and risks of ovulation prediction methods for timing intercourse on conception in couples trying to conceive.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility (CGF) Group Specialised Register, CENTRAL, MEDLINE, and Embase in January 2023. We also checked the reference lists of relevant studies and searched trial registries for any additional trials.

SELECTION CRITERIA

We included RCTs that compared methods of timed intercourse using ovulation prediction to other forms of ovulation prediction or intercourse without ovulation prediction in couples trying to conceive.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane to select and analyse studies in this review. The primary review outcomes were live birth and adverse events (such as depression and stress). Secondary outcomes were clinical pregnancy, pregnancy (clinical or positive urinary pregnancy test not yet confirmed by ultrasound), time to pregnancy, and quality of life. We assessed the overall quality of the evidence for the main comparisons using GRADE methods.

MAIN RESULTS

This review update included seven RCTs involving 2464 women or couples. Four of the five studies from the previous review were included in this update, and three new studies were added. We assessed the quality of the evidence as moderate to very low, the main limitations being imprecision, indirectness, and risk of bias. Urinary ovulation tests versus intercourse without ovulation prediction Compared to intercourse without ovulation prediction, urinary ovulation detection probably increases the chance of live birth in couples trying to conceive (risk ratio (RR) 1.36, 95% confidence interval (CI) 1.02 to 1.81, 1 RCT, n = 844, moderate-quality evidence). This suggests that if the chance of a live birth without urine ovulation prediction is 16%, the chance of a live birth with urine ovulation prediction is 16% to 28%. However, we are uncertain whether timed intercourse using urinary ovulation detection resulted in a difference in stress (mean difference (MD) 1.98, 95% CI -0.87 to 4.83, I² = 0%, P = 0.17, 1 RCT, n = 77, very low-quality evidence) or clinical pregnancy (RR 1.09, 95% CI 0.51 to 2.31, I² = 0%, 1 RCT, n = 148, low-quality evidence). Similar to the live birth result, timed intercourse using urinary ovulation detection probably increases the chances of clinical pregnancy or positive urine pregnancy test (RR 1.28, 95% CI 1.09 to 1.50, I² = 0, 4 RCTs, n = 2202, moderate-quality evidence). This suggests that if the chance of a clinical pregnancy or positive urine pregnancy test without ovulation prediction is assumed to be 18%, the chance following timed intercourse with urinary ovulation detection would be 20% to 28%. Evidence was insufficient to determine the effect of urine ovulation tests on time to pregnancy or quality of life. Fertility awareness-based methods (FABM) versus intercourse without ovulation prediction Due to insufficient evidence, we are uncertain whether timed intercourse using FABM resulted in a difference in live birth rate compared to intercourse without ovulation prediction (RR 0.95, 95% CI 0.76 to 1.20, I² = 0%, 2 RCTs, n = 157, low-quality evidence). We are also uncertain whether FABM affects stress (MD -1.10, 95% CI -3.88 to 1.68, 1 RCT, n = 183, very low-quality evidence). Similarly, we are uncertain of the effect of timed intercourse using FABM on anxiety (MD 0.5, 95% CI -0.52 to 1.52, P = 0.33, 1 RCT, n = 183, very low-quality evidence); depression (MD 0.4, 95% CI -0.28 to 1.08, P = 0.25, 1 RCT, n = 183, very low-quality evidence); or erectile dysfunction (MD 1.2, 95% CI -0.38 to 2.78, P = 0.14, 1 RCT, n = 183, very low-quality evidence). Evidence was insufficient to detect a benefit of timed intercourse using FABM on clinical pregnancy (RR 1.13, 95% CI 0.31 to 4.07, 1 RCT, n = 17, very low-quality evidence) or clinical or positive pregnancy test rates (RR 1.08, 95% CI 0.89 to 1.30, 3 RCTs, n = 262, very low-quality evidence). Finally, we are uncertain whether timed intercourse using FABM affects the time to pregnancy (hazard ratio 0.86, 95% CI 0.53 to 1.38, 1 RCT, n = 140, low-quality evidence) or quality of life. No studies assessed the use of timed intercourse with pelvic ultrasonography.

AUTHORS' CONCLUSIONS

The new evidence presented in this review update shows that timed intercourse using urine ovulation tests probably improves live birth and pregnancy rates (clinical or positive urine pregnancy tests but not yet confirmed by ultrasound) in women under 40, trying to conceive for less than 12 months, compared to intercourse without ovulation prediction. However, there are insufficient data to determine the effects of urine ovulation tests on adverse events, clinical pregnancy, time to pregnancy, and quality of life. Similarly, due to limited data, we are uncertain of the effect of FABM on pregnancy outcomes, adverse effects, and quality of life. Further research is therefore required to fully understand the safety and effectiveness of timed intercourse for couples trying to conceive. This research should include studies reporting clinically relevant outcomes such as live birth and adverse effects in fertile and infertile couples and utilise various methods to determine ovulation. Only with a comprehensive understanding of the risks and benefits of timed intercourse can recommendations be made for all couples trying to conceive.

Effects of trying to conceive using an every-other-day strategy versus fertile window monitoring on stress: a 12-month randomized controlled trial

STUDY QUESTION

Can animation videos on how to optimize the chances of pregnancy influence stress, anxiety, depression and sexual functioning of individuals trying to conceive (TTC)?

SUMMARY ANSWER

There were no differences between those educated to have intercourse every other day, on the fertile window and a control group (CG), and depression and sexual dysfunction significantly increased over time for all arms.

WHAT IS KNOWN ALREADY

Recent findings indicate that time to pregnancy can be significantly shortened by targeting the fertile period, but some reproductive care guidelines recommend instead the practice of intercourse every other day on the basis that it is less stressful to the couple. Evidence to support guidelines on how to preserve well-being and psychosocial adjustment and optimize pregnancy chances is lacking.

STUDY DESIGN, SIZE, DURATION

We conducted a prospective, double-blinded, three-arm randomized controlled trial between July 2016 and November 2019. Participants were randomized to either not having any stimulus (CG) or visualizing a short animated video explaining how to improve chances of pregnancy by having intercourse every other day (EOD group), or by monitoring the fertile window (FWM group). Assessments were made before the intervention (T0), and 6 weeks (T1), 6 months (T2) and 12 months after (T3), with follow-ups censored in case of pregnancy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were childless individuals of reproductive age actively TTC and not diagnosed or unaware of a condition that could prevent spontaneous pregnancy. Individuals were excluded from recruitment if they had previous children or had a condition preventing spontaneous pregnancy. Our primary outcome was stress and secondary outcomes included anxiety, depression, sexual functioning and pregnancy. Primary analyses were performed according to intention-to-treat principle.

MAIN RESULTS AND THE ROLE OF CHANCE

Of the 450 randomized participants 127 were educated to use an every-other-day strategy, 135 to monitor the fertile window, and 134 received no intervention. Groups were similar regarding demographics and months TTC. Repeated measures analysis revealed that there were no significant interaction effects of psychological and sexual well-being between groups over time (P > 0.05). Significant time effects were revealed for stress (F(3,855) = 4.94, P < 0.01), depression (F(3,855) = 14.22, P < 0.01) and sexual functioning (time effects P values <0.001 for female sexual functioning dimensions and <0.002 for male dimensions), but not for anxiety (F(2,299) = 0.51, P > 0.05). Stress levels lowered after 6 months (P < 0.001) and returned to baseline levels at the 1-year follow-up. Depressive symptomatology significantly increased at 6 weeks (P = 0.023), and again 1 year after (P = 0.001). There were also significant decreases in all female sexual functioning dimensions (desire, satisfaction, arousal, pain, orgasm and lubrication). In men, there were significant variations in orgasm, intercourse satisfaction and erectile function, but not desire and sexual satisfaction. Revealed pregnancy rates were 16% for participants in the EOD group, 30% for the FWM group and 20% for the CG. Pregnancies were not significantly different between arms: EOD vs FWM (odds ratio (OR) 2.32; 95% CI 0.92-5.83); EOD vs CG (OR 0.74; 95% CI 0.30-1.87); and FWM vs CG (OR 1.71; 95% CI 0.70-4.18).

LIMITATIONS, REASONS FOR CAUTION

Participants were recruited after transitioning to procreative sex. The study might be prone to bias as almost 30% of our sample fulfilled the chronological criterion for infertility, and other reproductive strategies could have been tried over time before recruitment.

WIDER IMPLICATIONS OF THE FINDINGS

Our data suggest that stress does not arise from feeling pressured on the fertile period and that advice on timing of intercourse might have to be personalized. The increasing levels of depression and sexual dysfunction over a year emphasize the crucial role of preconception care and fertility counseling in promoting psychological and sexual well-being.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by European Union Funds (FEDER/COMPETE-Operational Competitiveness Programme) and by national funds (FCT-Portuguese Foundation for Science and Technology) under the projects PTDC/MHC-PSC/4195/2012 and SFRH/BPD/85789/2012.

TRIAL REGISTRATION NUMBER

NCT02814006.

TRIAL REGISTRATION DATE

27 June 2016.

DATE OF FIRST PATIENT’S ENROLLMENT

19 July 2016.

Should home-based ovulation predictor kits be offered as an additional approach for fertility management for women and couples desiring pregnancy? A systematic review and meta-analysis

Introduction

To inform the WHO Guideline on self-care interventions, we conducted a systematic review of the impact of ovulation predictor kits (OPKs) on time-to-pregnancy, pregnancy, live birth, stress/anxiety, social harms/adverse events and values/preferences.

Methods

Included studies had to compare women desiring pregnancy who managed their fertility with and without OPKs, measure an outcome of interest and be published in a peer-reviewed journal. We searched for studies on PubMed, CINAHL, LILACS and EMBASE through November 2018. We assessed risk of bias assessed using the Cochrane tool for randomised controlled trials (RCTs) and the Evidence Project tool for observational studies, and conducted meta-analysis using random effects models to generate pooled estimates of relative risk (RR).

Results

Four studies (three RCTs and one observational study) including 1487 participants, all in high-income countries, were included. Quality of evidence was low. Two RCTs found no difference in time-to-pregnancy. All studies reported pregnancy rate, with mixed results: one RCT from the 1990s among couples with unexplained or male-factor infertility found no difference in clinical pregnancy rate (RR: 1.09, 95% CI 0.51 to 2.32); two more recent RCTs found higher self-reported pregnancy rates among OPK users (pooled RR: 1.40, 95% CI 1.08 to 1.80). A small observational study found higher rates of pregnancy with lab testing versus OPKs among women using donor insemination services. One RCT found no increase in stress/anxiety after two menstrual cycles using OPKs, besides a decline in positive affect. No studies measured live birth or social harms/adverse events. Six studies presented end-users’ values/preferences, with almost all women reporting feeling satisfied, comfortable and confident using OPKs.

Conclusion

A small evidence base, from high-income countries and with high risk of bias, suggests that home-based use of OPKs may improve fertility management when attempting to become pregnant with no meaningful increase in stress/anxiety and with high user acceptability.

Systematic review registration number

PROSPERO registration number CRD42019119402.

Detection of ovulation, a review of currently available methods

The ability to identify the precise time of ovulation is important for women who want to plan conception or practice contraception. Here, we review the current literature on various methods for detecting ovulation including a review of point‐of‐care device technology. We incorporate an examination of methods to detect ovulation that have been developed and practiced for decades and analyze the indications and limitations of each—transvaginal ultrasonography, urinary luteinizing hormone detection, serum progesterone and urinary pregnanediol 3‐glucuronide detection, urinary follicular stimulating hormone detection, basal body temperature monitoring, and cervical mucus and salivary ferning analysis. Some point‐of‐care ovulation detection devices have been developed and commercialized based on these methods, however previous research was limited by small sample size and an inconsistent standard reference to true ovulation.

Natural conception rates in subfertile couples following fertility awareness training

PURPOSE

To analyze cumulative pregnancy rates of subfertile couples after fertility awareness training.

METHODS

A prospective observational cohort study followed 187 subfertile women, who had received training in self-observation of the fertile phase of the menstrual cycle with the Sensiplan method, for 8 months. The women, aged 21-47 years, had attempted to become pregnant for 3.5 years on average (range 1-8 years) before study entry. Amenorrhea, known tubal occlusion and severe male factor had been excluded. An additional seven women, who had initially been recruited, became pregnant during the cycle immediately prior to Sensiplan training: this is taken to be the spontaneous pregnancy rate per cycle in the cohort in the absence of fertility awareness training.

RESULTS

The cumulative pregnancy rate of subfertile couples after fertility awareness training was 38% (95% CI 27-49%; 58 pregnancies) after eight observation months, which is significantly higher than the estimated basic pregnancy rate of 21.6% in untrained couples in the same cohort. For couples who had been seeking to become pregnant for 1-2 years, the pregnancy rate increased to 56% after 8 months. A female age above 35 (cumulative pregnancy rate 25%, p = 0.06), couples who had attempted to become pregnant for more than 2 years (cumulative pregnancy rate 17%, p < 0.01), all significantly reduce the chances of conceiving naturally at some point.

CONCLUSIONS

Training women to identify their fertile window in the menstrual cycle seems to be a reasonable first-line therapy in the management of subfertility.

Timed intercourse for couples trying to conceive

BACKGROUND

Fertility problems are very common, as subfertility affects about 10% to 15% of couples trying to conceive. There are many factors that may impact a couple's ability to conceive and one of these may be incorrect timing of intercourse. Conception is only possible from approximately five days before up to several hours after ovulation. Therefore, to be effective, intercourse must take place during this fertile period. 'Timed intercourse' is the practice of prospectively identifying ovulation and, thus, the fertile period to increase the likelihood of conception. Whilst timed intercourse may increase conception rates and reduce unnecessary intervention and costs, there may be associated adverse aspects including time consumption and stress. Ovulation prediction methods used for timing intercourse include urinary hormone measurement (luteinizing hormone (LH), estrogen), tracking basal body temperatures, cervical mucus investigation, calendar charting and ultrasonography. This review considered the evidence from randomised controlled trials for the use of timed intercourse on positive pregnancy outcomes.

OBJECTIVES

To assess the benefits and risks of ovulation prediction methods for timing intercourse on conception in couples trying to conceive.

SEARCH METHODS

We searched the following sources to identify relevant randomised controlled trials, the Menstrual Disorders and Subfertility Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, PubMed, LILACS, Web of Knowledge, the World Health Organization (WHO) Clinical Trials Register Platform and ClinicalTrials.gov. Furthermore, we manually searched the references of relevant articles. The search was not restricted by language or publication status. The last search was on 5 August 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing timed intercourse versus intercourse without ovulation prediction or comparing different methods of ovulation prediction for timing intercourse against each other in couples trying to conceive.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias and extracted the data. The primary review outcomes were cumulative live birth and adverse events (such as quality of life, depression and stress). Secondary outcomes were clinical pregnancy, pregnancy (clinical or self-reported pregnancy, not yet confirmed by ultrasound) and time to conception. We combined data to calculate pooled risk ratios (RRs) and 95% confidence intervals (CIs). Statistical heterogeneity was assessed using the I(2) statistic. We assessed the overall quality of the evidence for the main comparisons using GRADE methods.

MAIN RESULTS

We included five RCTs (2840 women or couples) comparing timed intercourse versus intercourse without ovulation prediction. Unfortunately one large study (n = 1453) reporting live birth and pregnancy had not published outcome data by randomised group and therefore could not be analysed. Consequently, four RCTs (n = 1387) were included in the meta-analysis. The evidence was of low to very low quality. Main limitations for downgrading the evidence included imprecision, lack of reporting clinically relevant outcomes and the high risk of publication bias.One study reported live birth, but the sample size was too small to draw any relevant conclusions on the effect of timed intercourse (RR 0.75, 95% CI 0.16 to 3.41, 1 RCT, n = 17, very low quality).One study reported stress as an adverse event. There was no evidence of a difference in levels of stress (mean difference 1.98, 95 CI% -0.87 to 4.83, 1 RCT, n = 77, low level evidence). No other studies reported adverse events.Two studies reported clinical pregnancy. There was no evidence of a difference in clinical pregnancy rates (RR 1.10, 95% CI 0.57 to 2.12, 2 RCTs, n = 177, I(2) = 0%, low level evidence). This suggested that if the chance of a clinical pregnancy following intercourse without ovulation prediction is assumed to be 16%, the chance of success following timed intercourse would be between 9% and 33%.Four studies reported pregnancy rate (clinical or self-reported pregnancy). Timed intercourse was associated with higher pregnancy rates compared to intercourse without ovulation prediction in couples trying to conceive (RR 1.35, 95% CI 1.06 to 1.71, 4 RCTs, n = 1387, I(2) = 0%, very low level evidence). This suggests that if the chance of a pregnancy following intercourse without ovulation prediction is assumed to be 13%, the chance following timed intercourse would be between 14% and 23%. Subgroup analysis by duration of subfertility showed no difference in effect between couples trying to conceive for < 12 months versus couples trying for ≥ 12 months. One trial reported time to conception data and showed no evidence of a difference in time to conception.

AUTHORS' CONCLUSIONS

There are insufficient data available to draw conclusions on the effectiveness of timed intercourse for the outcomes of live birth, adverse events and clinical pregnancy. Timed intercourse may improve pregnancy rates (clinical or self-reported pregnancy, not yet confirmed by ultrasound) compared to intercourse without ovulation prediction. The quality of this evidence is low to very low and therefore findings should be regarded with caution. There is a high risk of publication bias, as one large study remains unpublished 8 years after recruitment finished. Further research is required, reporting clinically relevant outcomes (live birth, clinical pregnancy rates and adverse effects), to determine if timed intercourse is safe and effective in couples trying to conceive.

Recruitment for longitudinal, randomised pregnancy trials initiated preconception: lessons from the effects of aspirin in gestation and reproduction trial

BACKGROUND

Recruitment into large, preconception randomised clinical trials (RCT) is challenging. We describe clinic and community-based preconception recruitment strategies for the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial and highlight approaches that were and were not successful. This longitudinal RCT was conducted at four major sites in the US. Eligible women had one to two prior pregnancy losses and were actively trying to become pregnant.

METHODS

Provider/clinic and community-based outreach strategies were utilised, and the recruitment rate and costs of methods were assessed.

RESULTS

A screening questionnaire was completed by 5485 women; 42.4% (n = 2323) screened were initially eligible, of whom 50.7% (n = 1228) were randomised. Provider/clinic-based recruitment yielded the highest number eligible of those screened (30.1%) and also the most randomised participants overall (40.3%). The next highest yield came from direct mail and brochures/flyers at 13.1% and 12.5% of women randomised, respectively. However, direct mailings cost $720 per participant randomised. Other than word of mouth, provider/clinic-based recruitment was the most cost effective method, costing an average of $60 per randomised participant. Web-based recruitment yielded 4.7% of participants at a cost of $278 per randomised participant.

CONCLUSIONS

Provider and clinic-based recruitment was the most effective and cost-efficient method of recruitment in a preconception intervention study of reproduction among women.

Joint analysis of longitudinal and survival data measured on nested timescales by using shared parameter models: an application to fecundity data

We consider the joint modelling, analysis and prediction of a longitudinal binary process and a discrete time-to-event outcome. We consider data from a prospective pregnancy study, which provides day level information regarding the behaviour of couples attempting to conceive. Reproductive epidemiologists are particularly interested in developing a model for individualized predictions of time to pregnancy (TTP). A couple's intercourse behaviour should be an integral part of such a model and is one of the main focuses of the paper. In our motivating data, the intercourse observations are a long series of binary data with a periodic probability of success and the amount of available intercourse data is a function of both the menstrual cycle length and TTP. Moreover, these variables are dependent and observed on different, and nested, timescales (TTP is measured in menstrual cycles whereas intercourse is measured on days within a menstrual cycle) further complicating its analysis. Here, we propose a semiparametric shared parameter model for the joint modelling of the binary longitudinal data (intercourse behaviour) and the discrete survival outcome (TTP). Further, we develop couple-based dynamic predictions for the intercourse profiles, which in turn are used to assess the risk for subfertility (i.e. TTP longer than six menstrual cycles).

The role of social media in recruiting for clinical trials in pregnancy

BACKGROUND

Recruitment of women in the periconceptional period to clinical studies using traditional advertising through medical establishments is difficult and slow. Given the widespread use of the internet as a source for medical information and research, we analyze the impact of social media in the second phase of an ongoing randomized, open-label clinical trial among pregnant women. This study aims to assess the effectiveness of social media as a recruitment tool through the comparison of diverse recruitment techniques in two different phases of the trial.

METHODS

Recruitment in Phase 1 of the study consisted solely of traditional healthcare-based sources. This was compared to Phase 2 of the study where traditional recruitment was continued and expanded, while social media was used as a supplementary source. Yearly recruitment and recruitment rates in the two phases were compared using the Mann Whitney U test. The contributions of each recruitment source to overall recruitment were analyzed, and the impact of potential confounders on recruitment rate was evaluated using a multiple regression and Interrupted Time Series Analysis.

RESULTS

In the first phase of the study, with over 56 months of recruitment using traditional sources, 35 women were enrolled in the study, resulting in a mean rate of ±0.62 recruits/month. In the 6 months implementing recruitment through social media, 45 women were recruited, for a 12-fold higher rate of ±7.5 recruits/month. Attrition rates remained constant, suggesting that social media had a positive impact on recruitment. The Interrupted Time Series Analysis detected a significant difference in recruitment after the intervention of social media (p<0.0001) with an evident increase in the number of recruits observed after the use of social media.

CONCLUSIONS

Clinicians and scientists recruiting for clinical studies should learn how to use online social media platforms to improve recruitment rates, thus increasing recruitment efficiency and cost-effectiveness.

Pilot test and validation of the peak day method of prospective determination of ovulation against a handheld urine hormone monitor

Background

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.

Methods

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.

Results

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%).

Conclusions

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.

Flexible Bayesian Human Fecundity Models

Human fecundity is an issue of considerable interest for both epidemiological and clinical audiences, and is dependent upon a couple's biologic capacity for reproduction coupled with behaviors that place a couple at risk for pregnancy. Bayesian hierarchical models have been proposed to better model the conception probabilities by accounting for the acts of intercourse around the day of ovulation, i.e., during the fertile window. These models can be viewed in the framework of a generalized nonlinear model with an exponential link. However, a fixed choice of link function may not always provide the best fit, leading to potentially biased estimates for probability of conception. Motivated by this, we propose a general class of models for fecundity by relaxing the choice of the link function under the generalized nonlinear model framework. We use a sample from the Oxford Conception Study (OCS) to illustrate the utility and fit of this general class of models for estimating human conception. Our findings reinforce the need for attention to be paid to the choice of link function in modeling conception, as it may bias the estimation of conception probabilities. Various properties of the proposed models are examined and a Markov chain Monte Carlo sampling algorithm was developed for implementing the Bayesian computations. The deviance information criterion measure and logarithm of pseudo marginal likelihood are used for guiding the choice of links. The supplemental material section contains technical details of the proof of the theorem stated in the paper, and contains further simulation results and analysis.

Preconception stress and the secondary sex ratio: a prospective cohort study

OBJECTIVE

To study the association between salivary stress biomarkers and the secondary sex ratio.

DESIGN

Prospective, longitudinal cohort study.

SETTING

Community setting in the United Kingdom.

PATIENT(S)

On discontinuation of contraception for purposes of becoming pregnant, 338 women aged 18-40 years with complete data (90%) were followed until pregnant or up to six menstrual cycles.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Secondary sex ratio.

RESULT(S)

Human chorionic gonadotropin pregnancies were detected in 207 (61%) women of whom 130 (63%) delivered singleton infants with available gender data. The adjusted odds ratio for a male birth was decreased for women in the highest quartile (AOR = 0.26; 95% confidence interval = 0.09, 0.74) of salivary cortisol relative to women in the lowest quartile during cycle 1. An inverse relation was observed between α-amylase and the 2° sex ratio, though not statistically significant.

CONCLUSION(S)

Our findings are consistent with a reversal in the 2° sex ratio with increasing preconception salivary cortisol concentrations. This relation suggests that activation of the hypothalamus-pituitary-adrenal axis may have implications in sex allocation and requires further study.

Are increased levels of self-reported psychosocial stress, anxiety, and depression associated with fecundity?

OBJECTIVE

To assess the association between self-reported measures of stress, anxiety, depression, and related constructs and fecundity.

DESIGN

Prospective cohort study of women trying to conceive.

SETTING

United Kingdom.

PATIENT(S)

Three hundred thirty-nine women aged 18-40 years who were attempting to conceive.

INTERVENTION(S)

Completed daily diaries for up to six cycles or until pregnancy was detected. For each cycle, stress biomarkers were measured and psychosocial questionnaires were completed.

MAIN OUTCOME MEASURES(S)

Fecundability odds ratios (FORs) and 95% confidence intervals were calculated using discrete time survival methods, and the day-specific probabilities of pregnancy were calculated using Bayesian statistical techniques.

RESULT(S)

Among the 339 women, 207 (61%) became pregnant during the study, 69 (20%) did not become pregnant, and 63 (19%) withdrew. After controlling for maternal age, parity, months trying to conceive before enrollment, smoking, caffeine use, and frequency of intercourse, we found no association between most psychosocial measures and FORs or the day-specific probabilities of pregnancy save for an increased FOR for women reporting higher versus lower levels of social support.

CONCLUSION(S)

Self-reported psychosocial stress, anxiety, and depression were not associated with fecundity. Any adverse effect of stress or psychological disturbance on fecundity does not appear to be detectable via the questionnaires administered.

Stress reduces conception probabilities across the fertile window: evidence in support of relaxation

OBJECTIVE

To assess salivary stress biomarkers (cortisol and α-amylase) and female fecundity.

DESIGN

Prospective cohort design.

SETTING

United Kingdom.

PATIENT(S)

274 women aged 18 to 40 years who were attempting pregnancy.

INTERVENTION(S)

Observation for six cycles or until pregnancy: women collected basal saliva samples on day 6 of each cycle, and used fertility monitors to identify ovulation and pregnancy test kits for pregnancy detection.

MAIN OUTCOME MEASURE(S)

Salivary cortisol (μg/dL) and α-amylase (U/mL) concentration measurements; fecundity measured by time-to-pregnancy and the probability of pregnancy during the fertile window as estimated from discrete-time survival and Bayesian modeling techniques, respectively.

RESULT(S)

Alpha-amylase but not cortisol concentrations were negatively associated with fecundity in the first cycle (fecundity odds ratio=0.85; 95% confidence interval 0.67, 1.09) after adjusting for the couples' ages, intercourse frequency, and alcohol consumption. Statistically significant reductions in the probability of conception across the fertile window during the first cycle attempting pregnancy were observed for women whose salivary concentrations of α-amylase were in the upper quartiles in comparison with women in the lower quartiles (highest posterior density: -0.284; 95% interval -0.540, -0.029).

CONCLUSION(S)

Stress significantly reduced the probability of conception each day during the fertile window, possibly exerting its effect through the sympathetic medullar pathway.

High-tech family planning: reproductive regulation through computerized fertility monitoring

Issues related to family planning have profound public health significance as they directly impact individuals, couples, and families throughout the world. A new method of family planning is now available using a computerized fertility monitor that accurately measures urinary surges in estrone-3-glucuronide (E3G) and luteinizing hormone (LH) prior to ovulation, thus identifying the short-lived fertile phase of the cycle and providing women with the choice to achieve or avoid conception. As well as ease of use and instruction, hand-held computerized fertility monitors are accurate and effective and can be used indefinitely. An algorithm for computerized monitoring is presented for use in situations of infrequent or irregular ovulation such as with polycystic ovarian syndrome and the post-partum period. Hormone-based fertility monitoring is compared to other computerized fertility monitoring techniques. A case series of seven reports reflecting varied clinical backgrounds and medical histories demonstrates broad-based success and high satisfaction with computerized monitoring for regulation of reproductive potential. Limitations of fertility monitoring are also discussed.

Workshop recommendations for the preconception cohort of the National Children's Study

This paper summarises discussions on incorporating preconception recruitment in the National Children's Study (NCS); these were part of the workshop on Expanding Methodologies for Capturing Day-Specific Probabilities of Conception. Four key issues were discussed in relation to the NCS: (1) differences between pregnancy 'planners' and 'non-planners'; (2) a tiered approach to preconception data collection; (3) data gaps in preconception studies; and (4) assessment of early pregnancy in subsequent pregnancies for women with a child already in the study. Practical recommendations were developed for each theme, which have relevance for other prospective studies of conception, pregnancy and human development.