Coital Frequency and the Probability of Pregnancy in Couples Trying to Conceive Their First Child: A Prospective Cohort Study in Japan

The probability of pregnancy in 100 episodes of sexual intercourse: A measure of male contraceptive performance

BACKGROUND

Accurately judging the efficacy of contraceptives is vital for preventing unintended pregnancy. The Pearl index and life table analysis describe female contraceptive performance. However, they are not ideal for quantifying male contraceptive efficacy given differences between male and female methods. In particular, male contraceptives like condoms are used "on demand" rather than long-term like female contraceptives. Additionally, the number of episodes of sexual intercourse, a key determinant of risk, is not considered. Lastly, men can father concurrent pregnancies in more than one woman. For these reasons, a male-specific measure may provide a more accurate measure of male contraceptive efficacy.

OBJECTIVES AND METHODS

As each episode of heterosexual intercourse within a fertile couple is associated with an approximately 3% risk of pregnancy, the chance of an unintended pregnancy with a given number of episodes of sexual intercourse can be modeled with and without contraceptives of various effectiveness.

RESULTS

Such modeling demonstrates that unintended pregnancy is strongly associated with both the number of episodes of sexual intercourse and the efficacy of the method. Based on these models, I propose a novel metric for male contraceptive efficacy called the Probability of Pregnancy100, defined as the percent chance of an unintended pregnancy occurring with 100 episodes of intercourse. Probability of Pregnancy100 should be easy for men to understand and is applicable to men with multiple sexual partners or men using "on-demand" contraceptives.

DISCUSSION AND CONCLUSIONS

The prevention of unintended pregnancy by a male contraceptive is strongly influenced by both method efficacy and sexual frequency. Probability of Pregnancy100 may offer a better measure of male contraceptive efficacy compared to the Pearl index and life table analysis as it takes sexual frequency into account; however, Probability of Pregnancy100 will need to be tested prospectively in male contraceptive studies alongside the Pearl index and life table analysis to determine its utility compared to these existing measures of contraceptive efficacy.

Clinical and Laboratorial Evaluation of Male Infertility. A Detailed Practical Approach

Infertility, defined as the inability to achieve pregnancy after one year of unprotected, frequent sexual intercourse, is a global burden that affects approximately 15% of couples, or 190-230 million people worldwide, who are trying to start a family. The male contributes significantly, directly accounting for 30-35% and up to 52% of total couple infertility, affecting approximately 7-8% of all men. This work aims to present, in a didactic and objective way, a standardization of the initial steps toward a thorough evaluation of subfertile and infertile men. We have focused on the evaluation of initial management, emphasizing the need for a comprehensive evaluation that includes a detailed history, physical examination, and semen analysis as the golden triple helix of basic evaluation of the infertile male. General and genital physical examinations are highly valuable due to the wealth of information they provide, from potential diagnoses to pregnancy prognoses. Comprehensive and quality-controlled semen analysis provides reliable information as a baseline test to evaluate the patency of the reproductive tract and to evaluate basic sperm parameters and fertility potential. However, it is not a fertility determinant and should preferentially be complemented with sperm functional tests. like biomarkers of oxidative stress, sperm immaturity and DNA fragmentation. Most cases of infertility require evaluation by a specialist in andrology, nonetheless the understanding and rationale of the initial assessment of the infertile male can be undertaken by non-specialists, thus improving the care and counseling of couples facing this troubling issue and avoiding unnecessary use of assisted reproductive technologies (ART) since most cases of male infertility can be treated and reversed by medical or surgical interventions, and the fertility status can be restored. The ultimate goal is to achieve natural pregnancy, the use of ART should not be the initial offered resource.

Sexual intercourse before embryo transfer in assisted reproductive technology might enhance probability of pregnancy: An observational study

BACKGROUND

Modifying the maternal immune system is necessary to facilitate embryo implantation. Modifying the immune system can occur in several ways, including maternal exposure to the partner's seminal plasma. Seminal plasma exposure can occur through sexual intercourse. To prove this theory, we investigate the effect of sexual intercourse on the chances of successful in vitro fertilization (IVF) in both fresh and frozen embryo transfer (ET) groups in terms of biochemical and clinical pregnancy.

METHODS

This is an observational analytical study with a retrospective cohort study design. This study compared biochemical and clinical pregnancy in patient groups who had sexual intercourse with those who did not have sexual intercourse during the IVF process. This study involved 132 participants.

RESULTS

The results of this study reported that there was no significant difference in pregnancy rates between patients who had sex before ET and those who did not have sex before ET. However, patients who experience orgasm during sex show significant rates of biochemical (p = 0.009) and clinical pregnancy (p = 0.027) rates.

CONCLUSIONS

Sexual intercourse did not show a significant difference between the groups who had sex before ET and those who did not have sex, but the experience of orgasm every time they had sex recently had a positive impact on reproductive health, especially pregnancy.

Holistic preconception care: Providing real-time guidance via a mobile app to optimise maternal and child health

Introduction

Preconception is a critical period to optimise gamete function and early placental development, essential for successful conception and long-term maternal-child health. However, there is a lack of preconception services and consequently, global fertility rates continue to fall and mothers embark on their pregnancy journey in poor health. There is an urgent need to implement a holistic community-level preconception care programme to optimise risk factors for poor fecundability and improve long-term maternal-child health.

Method

We reviewed current evidence on fecundability lifestyle risk factors, the efficacy of existing preconception interventions and the use of digital platforms for health optimisation, to create a new digital-based preconception intervention model that will be implemented via an app. We present the theory, content and mode of delivery of this holistic model targeting couples planning for pregnancy.

Results

We propose a new model featuring a user-friendly mobile app, which enables couples to self-assess fecundability risks through a personalised risk score that drives a tailored management plan. This tiered management provides anticipatory guidance supported by evidence-based recommen-dations, and promotes ongoing engagement for behavioural optimisation and specialist referrals as required. Based on the health belief model, this new model delivered with a mobile app seeks to shift couples' perceptions about their susceptibility and severity of subfertility, benefits of making a change and barriers to change.

Conclusion

Our proposed digital-based intervention model via a mobile app stands to enhance preconcep-tion care by providing personalised risk assessments, real-time feedback and tiered management to optimise preconception reproductive health of couples. This model forms a reference content framework for future preconception care intervention delivery.

Pre-Conceptional Anti-Thyroid Antibodies and Thyroid Function in Association with Natural Conception Rates

Thyroid functioning is an integral part of the endocrine system that supports conception and pregnancy. Frequent consumption of seafood and iodine by Japanese people may adversely affect their thyroid function. Thus, in this study, we aimed to analyze the associations between iodine intake, thyroid hormones, autoimmunity, and natural conception rates in Japanese women trying to conceive their first child. A prospective study of 24 weeks targeted 80 women with no history of infertility, who did not plan to undergo fertility treatment. Concentrations of urinary iodine concentration and thyroid biomarkers in the serum at enrollment were measured. Thirty-five women naturally conceived during the follow-up. The median (inter-quartile range) urinary concentration of iodine was 297 (165, 500) μg/L. Free triiodothyronine (T3) and free thyroxin (T4) negatively correlated with urinary iodine concentrations. Women with anti-thyroid peroxidase (anti-TPO) ≥ 16 IU/mL had lower conception rates (hazard ratio: 0.28, 95% confidence interval, 0.08-0.92) compared with those with anti-TPO < 16 IU/mL, after adjusting for age and coital frequency. None of anti-thyroglobulin antibody, free T3, free T4, or thyroid-stimulating hormone showed significant associations with conception rate after adjusting for age and coital frequency. The negative association between thyroid autoimmunity and natural conception rates warrants further investigation.

Casual Sex and Sexlessness in Japan: A Cross-Sectional Study

Low fertility has persisted in Japan for decades. Sexless marriages may indirectly contribute to low fertility. Inactive sexual lives within intimate and committed relationships may be linked to sexual activity outside such relationships, called “casual sex”. This study aimed to explore the correlates of casual sex and sexlessness. A web-based questionnaire survey was conducted among married and single men (n = 4000) aged 20–54 years in Japan. Sexlessness were reported by 56% of men, whereas 11% had had casual sex and 31% had had non-casual sex (with spouse, fiancé, or girlfriends/boyfriends) in the last month. Among married men, higher income and long working hours were positively associated with casual sex. Regarding never-married men: those with lower educational status and without full-time jobs were more likely to report casual sex, those in rural areas were more likely to be sexless than those in urban and suburban areas, and those with depression were more likely to be sexless than those without depression. Matching app use was strongly associated with casual sex among married and never-married men, suggesting that such tools may facilitate sexual activity outside committed and intimate relationships. Sexual behavior is closely linked to one’s social and economic environment and health status.