Caffeine intake and fecundability: a follow-up study among 430 Danish couples planning their first pregnancy

Diet and recreational drug use in relation to male reproductive health

Diet and lifestyle interventions present promising avenues for the improvement of male fertility. Our objective was to review and synthesize the existing observational and experimental studies among humans on the associations of diet and recreational drug use with semen quality and fertility outcomes. The available data on this topic are limited and, at times, conflicting. Nevertheless, on the basis of this review, dietary patterns that are composed of higher intakes of fruits, vegetables, whole grains, nuts, low-fat dairy, and seafood, as well as lower intakes of red and processed meats, sweets, and sugar-sweetened beverages were identified as having the strongest evidence for associations with better sperm quality. However, whether these dietary patterns translate into positive associations with clinical fertility endpoints such as assisted reproductive technology success rates or time-to-pregnancy among couples trying to conceive without medical assistance remains unclear. Male caffeine and alcohol intake, within low-to-moderate ranges of intake, do not appear to be detrimental to semen quality. Yet high-quality research on this topic, focused on clinical fertility endpoints, should continue given the conflicting evidence, particularly in populations undergoing infertility treatment with assisted reproductive technology. Recreational drug use, including marijuana, electronic cigarettes, and other illicit drugs, does not appear to be beneficial for male reproductive health and should be avoided or ceased. In conclusion, men should be encouraged to consume a healthy diet rich in fruits, vegetables, whole grains, nuts, low-fat dairy, and seafood, as well as lacking in red and processed meats, sweets, and sugar-sweetened beverages, and to avoid recreational drug use for improved male reproductive health.

Effect of Stress and Caffeine on Male Infertility

Caffeine is a natural psychoactive chemical found in beverages made from coffee. In addition, it is added by the manufacturers of a large number of sodas and energy drinks. It does this by stimulating both the brain and the central nervous system, enabling you to avoid being sleepy while still keeping you attentive. A state of emotional or physical tension is defined as stress. It can be induced through the experience of something or thinking of something that causes you to feel uncomfortable, irritated, or nervous. Your body's response to adversity or demand is what we call stress. Among couples, male infertility is common. A failure in spermatogenesis is accountable for nearly half of all occurrences of infertility in marriage. Ageing, psychological stress, diet, physical exercise, coffee, hot water, hot scrotum, and cell phone usage are some of the few modifiable lifestyle variables that have a role in the development of infertility. Many hypotheses have been proposed to establish the link between stress in the workplace, life events (war, earthquake, etc.), and inability to conceive have been linked to inferior or degraded semen quality. In this review, we will discuss the effect on male fertility of elements including quality of life (such as exercise, diet, and other alterations to one's daily routine) and psychological stress. In addition, the effects on male fertility of elevated scrotal temperature, improper dietary habits, and physical inactivity will be discussed. The loss in male fertility, mainly due to ageing, inappropriate lifestyles, and environmental factors, is a significant public health concern in this century. Couples can enhance their quality of life and increase their chances of naturally conceiving a child by altering their way of life and supplementing it with nutraceutical antioxidants and an organised educational, environmental, dietary, and physical exercise program.

Preconception caffeine metabolites, caffeinated beverage intake, and fecundability

BACKGROUND

Caffeine is the most frequently used psychoactive substance in the United States and >90% of reproductive-age women report some amount of intake daily. Despite biological plausibility, previous studies on caffeine and fecundability report conflicting results. Importantly, prior studies measured caffeine exposure exclusively by self-report, which is subject to measurement error and does not account for factors that influence caffeine metabolism.

OBJECTIVES

Our objective was to examine associations between preconception serum caffeine metabolites, caffeinated beverage intake, and fecundability.

METHODS

Participants included 1228 women aged 18-40 y with a history of 1-2 pregnancy losses in the EAGeR (Effects of Aspirin in Gestation and Reproduction) trial. We prospectively evaluated associations of preconception caffeine metabolites (i.e., caffeine, paraxanthine, and theobromine) measured from 1191 serum samples untimed to a specific time of day, self-reported usual caffeinated beverage intakes at baseline, and time-varying cycle-average caffeinated beverage intake, with fecundability. Using Cox proportional hazards models, we estimated fecundability odds ratios (FORs) and 95% CIs according to each metabolite. Follow-up was complete for 89% (n = 1088) of participants.

RESULTS

At baseline, 85%, 73%, and 91% of women had detectable serum caffeine, paraxanthine, and theobromine, respectively. A total of 797 women became pregnant during ≤6 cycles of preconception follow-up. After adjusting for potential confounders, neither serum caffeine [tertile (T)3 compared with T1 FOR: 0.87; 95% CI: 0.71, 1.08], paraxanthine (T3 compared with T1 FOR: 0.92; 95% CI: 0.75, 1.14), nor theobromine (T3 compared with T1 FOR: 1.15; 95% CI: 0.95, 1.40) were associated with fecundability. Baseline intake of total caffeinated beverages was not associated with fecundability (>3 compared with 0 servings/d adjusted FOR: 0.99; 95% CI: 0.74, 1.34), nor was caffeinated coffee (>2 compared with 0 servings/d adjusted FOR: 0.93; 95% CI: 0.45, 1.92) or caffeinated soda (>2 servings/d adjusted FOR: 0.92; 95% CI: 0.71, 1.20).

CONCLUSIONS

Our findings are reassuring that caffeine exposure from usual low to moderate caffeinated beverage intake likely does not influence fecundability.This trial was registered at clinicaltrials.gov as NCT00467363.

Nutrition, genetic variation and male fertility

Infertility affects nearly 50 million couples worldwide, with 40-50% of cases having a male factor component. It is well established that nutritional status impacts reproductive development, health and function, although the exact mechanisms have not been fully elucidated. Genetic variation that affects nutrient metabolism may impact fertility through nutrigenetic mechanisms. This review summarizes current knowledge on the role of several dietary components (vitamins A, B₁₂, C, D, E, folate, betaine, choline, calcium, iron, caffeine, fiber, sugar, dietary fat, and gluten) in male reproductive health. Evidence of gene-nutrient interactions and their potential effect on fertility is also examined. Understanding the relationship between genetic variation, nutrition and male fertility is key to developing personalized, DNA-based dietary recommendations to enhance the fertility of men who have difficulty conceiving.

Relationship between caffeine intake and infertility: a systematic review of controlled clinical studies

BACKGROUND

For a long time, the relationship between caffeine consumption and infertility in the general population is unclear, this study is aimed to systematically review the evidence from any type of controlled clinical studies to explore whether caffeine intake is a risk factor for human infertility.

METHODS

Seven databases were searched from inception to May 2019. We included women/men without a history of infertility but were willing to have children in prospective studies and women/men who were diagnosed with infertility in retrospective studies. The observed exposure factor should be caffeine or caffeine containing beverage. Diagnosis of infertility or not for participants was the key outcome. The Newcastle-Ottawa scale (NOS) or Cochrane risk of bias tool were used to assess the methodological quality of included studies. Meta-analysis was conducted if there were acceptable clinical and statistical heterogeneity among studies. The GRADE method was used to assess the certainty of the evidence.

RESULTS

Four studies (one cohort study and three case-control studies) involving 12,912 participants were included. According NOS, the average score of case-control studies was 6, and the cohort study achieved 9. Meta-analysis and subgroup analysis were conducted. The results showed that low (OR 0.95, 95%CI 0.78-1.16), medium (OR 1.14, 95%CI 0.69-1.86) and high doses (OR 1.86, 95%CI 0.28-12.22) of caffeine intake may not increase the risk of infertility. The quality of the current evidence bodies were all low.

CONCLUSION

Our study provides low quality evidence that regardless of low, medium and high doses of caffeine intake do not appear increase the risk of infertility. But the conclusion should be treated with caution.

Substance Abuse and Male Hypogonadism

Progressive deterioration of male reproductive function is occurring in Western countries. Environmental factors and unhealthy lifestyles have been implicated in the decline of testosterone levels and sperm production observed in the last fifty years. Among unhealthy lifestyles, substance and drug abuse is a recognized cause of possible alterations of steroidogenesis and spermatogenesis. Alcohol, opioids and anabolic-androgenic steroids are capable to reduce testosterone production in male interfering with testicular and/or hypothalamic-pituitary function. Other substances such as nicotine, cannabis, and amphetamines alter spermatogenesis inducing oxidative stress and subsequent apoptosis in testicular tissue. Substance and drug abuse is a potentially reversible cause of hypogonadism, defined as the failure of the testis to produce physiological concentrations of testosterone and/or a normal number of spermatozoa. The identification of the abuse is important because the withdrawal of substance intake can reverse the clinical syndrome. This review summarizes the most important clinical and experimental evidence on the effect of substance abuse on testosterone and sperm production.

Impact of female daily coffee consumption on successful fertility treatment: a Danish cohort study

OBJECTIVE

To investigate whether female coffee consumption affects the chance of achieving a clinical pregnancy and a live birth among women and couples receiving medically assisted reproduction (MAR) treatment.

DESIGN

Cohort study with prospectively collected exposure data.

SETTING

Public fertility clinic.

PATIENT(S)

A total of 1,708 women and potential partners undergoing fertility treatment, contributing with 1,511 intrauterine insemination (IUI) cycles, 2,870 in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles, and 1,355 frozen embryo transfer cycles.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy and live birth in consecutive treatment cycles in the Danish national health registries, enabling complete follow-up, and estimation of the cumulative chance of live birth for three consecutive treatment cycles.

RESULT(S)

Among women receiving IVF or ICSI treatment, coffee consumption did not seem to affect the chance of achieving a clinical pregnancy and a live birth. Women treated with IUI who had a daily coffee consumption of 1-5 cups were more likely to achieve a clinical pregnancy (adjusted relative risk 1.49; 95% confidence interval, 1.05-2.11) and live birth (adjusted relative risk 1.53; 95% confidence interval, 1.06-2.21) compared with the reference group of coffee abstainers.

CONCLUSION(S)

Women consuming 1-5 cups versus none had a 1.5-fold higher probability of achieving a pregnancy or a live birth when receiving IUI. No associations were found, however, between women's daily coffee consumption and achieving a pregnancy or a live birth from IVF/ICSI.

Intake of Sugar-sweetened Beverages and Fecundability in a North American Preconception Cohort

BACKGROUND

Dietary factors, including sugar-sweetened beverages, may have adverse effects on fertility. Sugar-sweetened beverages were associated with poor semen quality in cross-sectional studies, and female soda intake has been associated with lower fecundability in some studies.

METHODS

We evaluated the association of female and male sugar-sweetened beverage intake with fecundability among 3,828 women planning pregnancy and 1,045 of their male partners in a North American prospective cohort study. We followed participants until pregnancy or for up to 12 menstrual cycles. Eligible women were aged 21-45 (male partners ≥21), attempting conception for ≤6 cycles, and not using fertility treatments. Participants completed a comprehensive baseline questionnaire, including questions on sugar-sweetened beverage consumption during the previous 4 weeks. We estimated time-to-pregnancy from follow-up questionnaires completed every 2 months by the female partner. We calculated adjusted fecundability ratios (FR) and 95% confidence intervals (CIs) according to intake of sugar- sweetened beverages using proportional probabilities regression.

RESULTS

Both female and male intakes of sugar-sweetened beverages were associated with reduced fecundability (FR = 0.81; 95% CI = 0.70, 0.94 and 0.78; 95% CI = 0.63, 0.95 for ≥7 sugar-sweetened beverages per week compared with none, for females and males, respectively). Fecundability was further reduced among those who drank ≥7 servings per week of sugar-sweetened sodas (FR = 0.75, 95% CI = 0.59, 0.95 for females and 0.67, 95% CI = 0.51, 0.89 for males).

CONCLUSIONS

Sugar-sweetened beverages, particularly sodas and energy drinks, were associated with lower fecundability, but diet soda and fruit juice had little association.

Potential nutraceutical and food additive properties and risks of coffee: a comprehensive overview

Coffee is a composite mixture of more than a thousand diverse phytochemicals like alkaloids, phenolic compounds, vitamins, carbohydrates, lipids, minerals and nitrogenous compounds. Coffee has multifunctional properties as a food additive and nutraceutical. As a nutraceutical, coffee has anti-inflammatory, anti-oxidant, antidyslipidemic, anti-obesity, type-2 diabetes mellitus (DM), and cardiovascular diseases (CVD), which can serve for the treatment and prevention of metabolic syndrome and associated disorders. On the other hand, as a food additive, coffee has antimicrobial activity against a wide range of microorganisms, inhibits lipid peroxidation (LPO), and can function as a prebiotic. The outcomes of different studies also revealed that coffee intake may reduce the incidence of numerous chronic diseases, like liver disease, mental health, and it also overcomes the all-cause mortality, and suicidal risks. In some studies, high intake of coffee is linked to increase CVD risk factors, like cholesterol, plasma homocysteine and blood pressure (BP). There is also a little evidence that associated the coffee consumption with increased risk of lung tumors in smokers. Among adults who consume the moderate amount of coffee, there is slight indication of health hazards with strong indicators of health benefits. Moreover, existing literature suggests that it may be cautious for pregnant women to eliminate the chances of miscarriages and impaired fetal growth. The primary purpose of this narrative review is to provide an overview of the findings of the positive impacts and risks of coffee consumption on human health. In conclusion, to date, the best available evidence from research indicates that drinking coffee up to 3-4 cups/day provides health benefits for most people.

Caffeine, alcohol, smoking, and reproductive outcomes among couples undergoing assisted reproductive technology treatments

During the past decade, as the use of assisted reproductive technologies (ART) has continued to increase worldwide, research investigating whether modifiable lifestyle factors, such as alcohol, caffeine, and smoking, may affect ART outcomes has grown. Despite the vast literature, there is still uncertainty regarding the effects of some of these exposures on ART outcomes. The objective of this review is to summarize the epidemiologic literature on intakes of caffeine and alcohol, smoking, and reproductive outcomes among women undergoing ART. Of the five epidemiologic studies on caffeine intake and ART outcomes, only one found a significant negative effect of caffeine intake on live birth following ART. There have been six epidemiologic studies exploring whether alcohol intake is associated with fertility outcomes among women undergoing ART. Three studies assessed current alcohol consumption and observed a negative effect on outcomes such as fertilization, embryo quality, and implantation. When alcohol intake in the year before treatment was assessed, no relationships were observed with clinical outcomes following ART. Finally, numerous epidemiologic studies and a handful of meta-analyses have confirmed that female current smokers have worse ART outcomes compared with nonsmokers. Although former smokers tend to have better ART outcomes than current smokers, very few individual studies have investigated the influence of smoking cessation on ART outcomes. Literature on male smoking, drinking, and caffeine habits in relation to ART outcomes is even sparser and inconsistent, making it difficult to draw strong conclusions on that topic. In summary, there is little evidence supporting a detrimental effect of moderate caffeine intake on ART outcomes. Current consumption of alcohol may have a negative effect on ART outcomes, but at present the evidence is limited. Women who currently smoke cigarettes have been consistently found to have poorer ART outcomes, including reduced live birth rates, but a quantification of the benefits of smoking cessation is lacking.

Diet and fertility: a review

The literature on the relationship between diet and human fertility has greatly expanded over the last decade, resulting in the identification of a few clear patterns. Intake of supplemental folic acid, particularly at doses higher than those recommended for the prevention of neural tube defects, has been consistently related to lower frequency of infertility, lower risk of pregnancy loss, and greater success in infertility treatment. On the other hand and despite promising evidence from animal models, vitamin D does not appear to exert an important role in human fertility in the absence of deficiency. Antioxidant supplementation does not appear to offer any benefits to women undergoing infertility treatment, but it appears to be beneficial when it is the male partner who is supplemented. However, the available evidence does not allow discerning which specific antioxidants, or at which doses, are responsible for this benefit. Long-chain omega-3 fatty acids appear to improve female fertility, although it remains unclear to what extent contamination of shared food sources, such as fish with high levels of environmental toxicants, can dampen this benefit. Lastly, adherence to healthy diets favoring seafood, poultry, whole grains, fruits, and vegetables are related to better fertility in women and better semen quality in men. The cumulative evidence has also piled against popular hypotheses. Dairy and soy, once proposed as reproductive toxicants, have not been consistently related to poor fertility. In fact, soy and soy supplements appear to exert a beneficial effect among women undergoing infertility treatment. Similarly, because data from large, high-quality studies continue to accumulate, the evidence of a potentially deleterious effect of moderate alcohol and caffeine intake on the ability to become pregnant seems less solid than it once did. While a complete picture of the role of nutrition on fertility is far from complete, much progress has been made. The most salient gaps in the current evidence include jointly considering female and male diets and testing the most consistent findings in randomized trials.

Coffee, tea and caffeine consumption and risk of primary infertility in women: a Danish cohort study

INTRODUCTION

The aim of this study was to investigate whether consumption of coffee, tea and caffeine affects the risk of primary infertility in women.

MATERIAL AND METHODS

We selected nulliparous Danish women aged 20-29 years from a prospective cohort and retrieved information on coffee and tea consumption from a questionnaire and an interview at enrollment. We assessed the women's fertility by linkage to the Danish Infertility Cohort and retrieved information on children and vital status from the Civil Registration System. All 7574 women included for analysis were followed for primary infertility from the date of enrollment (1991-1993) until 31 December 2010. Analyses were performed with Cox proportional hazard models.

RESULTS

During follow up, primary infertility was diagnosed in 822 women. Compared with never consumers, the risk of primary infertility among women who drank coffee or tea was not affected. The risk of primary infertility was neither associated with an increasing number of daily servings of coffee (hazard ratio 1.00; 95% confidence interval (CI), 0.97-1.03) or tea (hazard ratio 1.01; 95% CI, 0.99-1.03) in consumers only. Concerning total caffeine consumption (from coffee and tea), the risk of infertility was similar among consumers compared with never consumers. Finally, none of the additional daily 100 mg of caffeine affected the risk among consumers only (hazard ratio 1.00; 95% CI 0.98-1.02).

CONCLUSIONS

In this population-based cohort study, not restricted to women seeking pregnancy, we found no association between coffee, tea or total caffeine consumption and the risk of primary infertility in women.

Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis

Objective

The aim was to investigate whether coffee or caffeine consumption is associated with reproductive endpoints among women with natural fertility (ie, time to pregnancy [TTP] and spontaneous abortion [SAB]) and among women in fertility treatment (ie, clinical pregnancy rate or live birth rate).

Design

This study was a systematic review and dose-response meta-analysis including data from case-control and cohort studies.

Methods

An extensive literature search was conducted in MEDLINE and Embase, with no time and language restrictions. Also, reference lists were searched manually. Two independent reviewers assessed the manuscript quality using the Newcastle-Ottawa Scale (NOS). A two-stage dose-response meta-analysis was applied to assess a potential association between coffee/caffeine consumption and the outcomes: TTP, SAB, clinical pregnancy, and live birth. Heterogeneity between studies was assessed using Cochrane Q-test and I² statistics. Publication bias was assessed using Egger's regression test.

Results

The pooled results showed that coffee/caffeine consumption is associated with a significantly increased risk of SAB for 300 mg caffeine/day (relative risk [RR]: 1.37, 95% confidence interval [95% CI]: 1.19; 1.57) and for 600 mg caffeine/day (RR: 2.32, 95% CI: 1.62; 3.31). No association was found between coffee/caffeine consumption and outcomes of fertility treatment (based on two studies). No clear association was found between exposure to coffee/caffeine and natural fertility as measured by fecundability odds ratio (based on three studies) or waiting TTP (based on two studies).

Conclusion

Results from this meta-analysis support the growing evidence of an association between coffee/caffeine intake and the risk of SAB. However, viewing the reproductive capacity in a broader perspective, there seems to be little, if any, association between coffee/caffeine consumption and fecundity. In general, results from this study are supportive of a precautionary principle advised by health organizations such as European Food Safety Authority (EFSA) and World Health Organization (WHO), although the advised limit of a maximum of two to three cups of coffee/200-300 mg caffeine per day may be too high.

Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies

BACKGROUND

Infertility is a global public health issue, affecting 15% of all couples of reproductive age. Male factors, including decreased semen quality, are responsible for ~25% of these cases. The dietary pattern, the components of the diet and nutrients have been studied as possible determinants of sperm function and/or fertility.

OBJECTIVE AND RATIONALE

Previous systematic reviews have been made of the few heterogeneous low-quality randomized clinical trials (RCTs) conducted in small samples of participants and investigating the effect of specific nutrients and nutritional supplements on male infertility. However, as yet there has been no systematic review of observational studies.

SEARCH METHODS

A comprehensive systematic review was made of the published literature, from the earliest available online indexing year to November 2016, in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We have included cross-sectional, case-control and prospective and retrospective studies in which fertile/infertile men were well defined (men with sperm disorders, sperm DNA damage, varicocele or idiopathic infertility). The primary outcomes were semen quality or fecundability. With the data extracted, we evaluated and scored the quality of the studies selected. We excluded RCTs, animal studies, review articles and low-quality studies.

OUTCOMES

A total of 1944 articles were identified, of which 35 were selected for qualitative analysis. Generally, the results indicated that healthy diets rich in some nutrients such as omega-3 fatty acids, some antioxidants (vitamin E, vitamin C, β-carotene, selenium, zinc, cryptoxanthin and lycopene), other vitamins (vitamin D and folate) and low in saturated fatty acids and trans-fatty acids were inversely associated with low semen quality parameters. Fish, shellfish and seafood, poultry, cereals, vegetables and fruits, low-fat dairy and skimmed milk were positively associated with several sperm quality parameters. However, diets rich in processed meat, soy foods, potatoes, full-fat dairy and total dairy products, cheese, coffee, alcohol, sugar-sweetened beverages and sweets have been detrimentally associated with the quality of semen in some studies. As far as fecundability is concerned, a high intake of alcohol, caffeine and red meat and processed meat by males has a negative influence on the chance of pregnancy or fertilization rates in their partners.

WIDER IMPLICATIONS

Male adherence to a healthy diet could improve semen quality and fecundability rates. Since observational studies may prove associations but not causation, the associations summarized in the present review need to be confirmed with large prospective cohort studies and especially with well-designed RCTs.

Association between preconception maternal beverage intake and in vitro fertilization outcomes

OBJECTIVE

To study whether maternal intake of beverage type affects IVF outcomes.

DESIGN

A prospective study.

SETTING

Tertiary, university-affiliated center.

PATIENT(S)

Three hundred forty women undergoing IVF from 2014 through 2016 for infertility as well as for pregenetic diagnosis for autosomal recessive diseases were enrolled during ovarian stimulation and completed a questionnaire describing their usual beverage consumption.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

IVF outcomes were abstracted from medical records. Total caffeine intake was estimated by summing the caffeine content for specific beverages multiplied by frequency of intake. Associations between specific types of beverages and IVF outcomes were analyzed using Poisson and logistic regression models adjusting for possible confounders.

RESULT(S)

Higher intake of sugared soda was associated with lower total, mature, and fertilized oocytes and top-quality embryos after ovarian stimulation. Women who consumed sugared soda had, on average, 1.1 fewer oocytes retrieved, 1.2 fewer mature oocytes retrieved, 0.6 fewer fertilized oocytes, and 0.6 fewer top-quality embryos compared with women who did not consume sugared soda. Furthermore, compared with women who did not drink sugared soda, the adjusted difference in percent of cycles resulting in live birth for women consuming 0.1-1 cups/day and >1 cup/day were -12% and -16%, respectively. No associations were found between consumption of coffee, caffeine, or diet sodas and IVF outcome.

CONCLUSION(S)

Sugared beverages, independent of their caffeine content, may be a bigger threat to reproductive success than caffeine and caffeinated beverages without added sugar.

Ovotoxicity of cigarette smoke: A systematic review of the literature

This study reviews the scientific literature on the noxious effects of cigarette smoke on the ovarian follicle, and the cumulative data on the impact of smoking on in vitro fertilization (IVF) cycle outcome. There is a close association between tobacco smoke and accelerated follicle loss, abnormal follicle growth and impairment of oocyte morphology and maturation. There is an increasing amount of evidence indicating that smoke can directly derange folliculogenesis. Increased cellular apoptosis or autophagy, DNA damage and abnormal crosstalk between oocyte and granulosa cells have been implicated in the demise of ovarian follicles. It becomes increasingly clear that maternal smoking can exert multigenerational effects on the ovarian function of the progeny. Growing evidence suggests that cigarette smoke is associated with decreased results after IVF. Further research is needed to better define the molecular mechanisms behind smoking-induced ovarian disruption.

Coffee and caffeine intake and male infertility: a systematic review

BACKGROUND

Semen quality, a predictor of male fertility, has been suggested declining worldwide. Among other life style factors, male coffee/caffeine consumption was hypothesized to influence semen parameters, but also sperm DNA integrity. To summarize available evidence, we performed a systematic review of observational studies on the relation between coffee/caffeine intake and parameters of male fertility including sperm ploidy, sperm DNA integrity, semen quality and time to pregnancy.

METHODS

A systematic literature search was performed up to November 2016 (MEDLINE and EMBASE). We included all observational papers that reported the relation between male coffee/caffeine intake and reproductive outcomes: 1. semen parameters, 2. sperm DNA characteristics, 3. fecundability. All pertinent reports were retrieved and the relative reference lists were systematically searched in order to identify any potential additional studies that could be included.

RESULTS

We retrieved 28 papers reporting observational information on coffee/caffeine intake and reproductive outcomes. Overall, they included 19,967 men. 1. Semen parameters did not seem affected by caffeine intake, at least caffeine from coffee, tea and cocoa drinks, in most studies. Conversely, other contributions suggested a negative effect of cola-containing beverages and caffeine-containing soft drinks on semen volume, count and concentration. 2. As regards sperm DNA defects, caffeine intake seemed associated with aneuploidy and DNA breaks, but not with other markers of DNA damage. 3. Finally, male coffee drinking was associated to prolonged time to pregnancy in some, but not all, studies.

CONCLUSIONS

The literature suggests that caffeine intake, possibly through sperm DNA damage, may negatively affect male reproductive function. Evidence from epidemiological studies on semen parameters and fertility is however inconsistent and inconclusive. Well-designed studies with predefined criteria for semen analysis, subject selection, and life style habits definition, are essential to reach a consistent evidence on the effect of caffeine on semen parameters and male fertility.

Male caffeine and alcohol intake in relation to semen parameters and in vitro fertilization outcomes among fertility patients

Much of the literature on the impact of male caffeine and alcohol intake on reproductive outcomes has utilized semen quality as a proxy for male fertility, although semen parameters have a limited predictive value for spontaneous pregnancy. The objective of this study was to investigate whether male caffeine and alcohol intakes are associated with semen parameters and assisted reproductive technology outcome. The Environment and Reproductive Health Study, an ongoing prospective cohort study, enrolls subfertile couples presenting for treatment at an academic fertility center (2007-2012). A total of 171 men with 338 semen analyses and 205 assisted reproductive technology cycles were included in this analysis. Diet was assessed using a 131-item food frequency questionnaire. Mixed models adjusting for potential confounders were used to evaluate the relationships of male caffeine and alcohol intakes with semen parameters and assisted reproductive technology outcomes. There was no association between male caffeine and alcohol intake and semen quality. Male caffeine intake was negatively related to live birth after assisted reproductive technologies (p-trend < 0.01), and male alcohol intake was positively related to live birth after assisted reproductive technologies (p-trend = 0.04). Adjusted live birth rate among couples with a male partner in the highest quartile of caffeine intake (≥272 mg/day) compared to couples with a male partner in the lowest quartile of intake (<99 mg/day) was 19% vs. 55%, respectively, p < 0.01. In terms of alcohol intake, adjusted live birth rate among couples with a male partner in the highest quartile of alcohol intake (≥22 g/day) compared to couples with a male partner in the lowest quartile of intake (<3 g/day) was 61% vs. 28%, respectively, p = 0.05. In conclusion, male pre-treatment caffeine and alcohol intakes were associated with live birth after assisted reproductive technologies, but not with semen parameters, among fertility patients.

The influence of age at menarche, menstrual cycle length and bleeding duration on time to pregnancy: a large prospective cohort study among rural Chinese women

OBJECTIVE

To investigate the relations among age at menarche (AAM), menstrual cycle length, menstrual bleeding duration and time to pregnancy in a large cohort of rural Chinese women.

DESIGN

A prospective cohort study.

SETTING

Local family-planning service agencies and maternal/child care service centres.

POPULATION

A total of 391 320 rural women of reproductive age who participated in the National Free Pre-pregnancy Checkups and were planning to conceive were enrolled.

METHODS

Menstrual characteristics were collected via face-to-face interviews. The Cox proportional hazards model were used to estimate the fecundability ratios (FRs) and 95% confidence intervals for each measure relative to its reference category.

MAIN OUTCOME MEASURES

Time to pregnancy.

RESULTS

Women with an AAM later than 14 years of age were less likely become pregnant compared with women with AAM at 13-14 years of age (FR 0.93, 95% CI 0.92-0.94). Those with menstrual cycle lengths >29 days were less likely to come pregnant (FR 0.91, 95% CI 0.90-0.92) compared with the reference cycle length of 27-29 days. Women with bleeding durations of <4 (FR 0.88; 95% CI 0.86-0.91) or >5 days (FR 0.91; 95% CI 0.90-0.91) showed lower FRs compared with those reporting 4-5 days of bleeding. The associations were independent of maternal age, ethnicity, education level, occupation, tobacco use, alcohol use and body mass index.

CONCLUSION

A later onset of menarche, longer menstrual cycle length, both shorter (<4 days) and longer (>5 days) bleeding duration were associated with a lower FR and longer time to pregnancy in rural Chinese women.

TWEETABLE ABSTRACT

A later menarche, longer cycle, shorter or longer bleeding duration were associated with lower fecundity.

Phosphodiesterase Inhibitors (PDE Inhibitors) and Male Reproduction

The nonspecific PDE inhibitors, particularly the methylxanthines: caffeine, pentoxifylline (PTX), and theophylline, are known to stimulate sperm motility in vitro and have been used to treat sperm prior to insemination. The in vivo effects are less dramatic. A beneficial effect of caffeine, which is a constituent of some medications, remains controversial. Very high doses of caffeine do have negative effects on fertility endpoints in men and experimental species. The specific PDE5 inhibitors, particularly sildenafil and tadalafil, are prescribed for erectile dysfunction, as well as pulmonary hypertension, lower urinary tract symptoms, and premature ejaculation. PDE5 is expressed throughout the contractile tissues of the male reproductive tract, generally increasing contractility. Some PDE5 inhibitors tend to increase circulating testosterone levels somewhat. For short-term exposure consistent with use prior to intercourse, there appears to be minimal effects on semen quality. Several large, randomized controlled trials (RCTs) in healthy men have not found adverse effects of long-term use of these drugs on semen quality. RCTs in infertile men have demonstrated a modest increase in semen quality. Animal studies at human equivalent doses (HED) have produced similar results in young males, but a study in aging male rats found progressive decreases in epididymal sperm quality accompanied by consistent degeneration of the seminal tubules suggesting that studies in older men might be warranted. A concerning study in mice found lower fertilization rates in males treated with HED of sildenafil and mated the next day to untreated females than for control males. Fertility studies in humans are needed.

Implication of caffeine consumption and recovery on the reproductive functions of adult male Wistar rats

BACKGROUND

This study assessed the impact of caffeine consumption and recovery on reproductive functions and fertility of Wistar rats.

METHODS

Thirty-five adult male Wistar rats were divided into seven groups of five rats each. Group A (control) received distilled water (vehicle), while groups B, C, and D were treated orally with 10 mg/kg body weight (BW), 20 mg/kg BW, and 40 mg/kg BW caffeine, respectively, for 30 days. Groups E, F, and G were treated orally with 10 mg/kg BW, 20 mg/kg BW, and 40 mg/kg BW caffeine, respectively, for 30 days and then allowed to recover for another 30 days.

RESULTS

Caffeine caused a decrease in body weight, while recovery groups showed appreciable increase in body weight during recovery. Relative weight of seminal vesicle, prostate, and epididymis decreased dose dependently during treatment but increased during recovery. The liver and kidney weight increased during treatment but reduced during recovery. Sperm count was significantly decreased in both treated and recovery groups. Initial decrease in sperm viability and volume was appreciably reversed during recovery period. Serum level of testosterone increased at high doses, while serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) showed significant decrease. Histological sections of testis in treated groups showed mild congestion of the interstitial blood vessel and subcapsular congestion. However, there was no subcapsular congestion in the recovery groups. All rats in both treated and recovery groups had 100% fertilization success from fertility study.

CONCLUSIONS

Suggestively, caffeine treatment for 4 weeks could impair body, reproductive organs weight, sperm characteristics, LH/FSH level, and also testicular cyto-architecture. Effects appeared, however, reversible after caffeine withdrawal.

Complications and Safety of Preconception Low-Dose Aspirin Among Women With Prior Pregnancy Losses

OBJECTIVE

To evaluate complications and safety of preconception low-dose aspirin in 1,228 U.S. women (2007-2011).

METHODS

Evaluation of the safety of low-dose aspirin in the participants and their fetuses was a planned secondary analysis of the Effects of Aspirin in Gestation and Reproduction trial, a multicenter, block-randomized, double-blind, placebo-controlled trial investigating the effect of low-dose aspirin on the incidence of live birth. Women aged 18-40 years with a history of one to two pregnancy losses trying to conceive were randomized to daily low-dose aspirin (81 mg, n=615) or placebo (n=613) and were followed for up to six menstrual cycles or through gestation if they became pregnant. Emergency care visits and possible aspirin-related symptoms were assessed at each study follow-up using standardized safety interviews. In addition, complications for both the participant and her fetus or neonate were captured prospectively using case report forms, interviews conducted during pregnancy and postpartum, and medical records.

RESULTS

The proportion of women with at least one possible aspirin-related symptom during the trial was similar between treatment arms (456 [74%] low-dose aspirin compared with 447 [73%] placebo, P=.65) as was the proportion with at least one emergency care visit (104 [17%] low-dose aspirin compared with 99 [16%] placebo, P=.76). Maternal complications were evenly distributed by treatment arm with the exception of vaginal bleeding, which was more commonly reported in the low-dose aspirin arm (22% compared with 17%, P=.02). The distribution of fetal and neonatal complications-which included three stillbirths, three neonatal deaths, and 10 neonates with birth defect(s)-was similar between treatment arms.

CONCLUSION

Although rare but serious complications resulting from low-dose aspirin cannot be ruled out, preconception low-dose aspirin appears to be well tolerated by women trying to conceive, women who become pregnant, and by their fetuses and neonates.

Caffeine and caffeinated beverage consumption and fecundability in a preconception cohort

Caffeine is an adenosine receptor antagonist that may influence fertility by affecting ovulation, menstrual characteristics, or sperm quality. We studied the association between female and male preconception caffeine intake and fecundability in a North American prospective cohort study of 2135 pregnancy planners. Frequency of caffeinated beverage intake was self-reported at baseline. Outcome data were updated every 8 weeks until reported pregnancy; censoring occurred at 12 months. Adjusted fecundability ratios (FR) and 95% confidence intervals (CI) were estimated using proportional probabilities regression. Total caffeine intake among males, but not females, was associated with fecundability (FR for ≥300 vs. <100mg/day caffeine among males=0.72, 95% CI=0.54-0.96), although the association was not monotonic. With respect to individual beverages, caffeinated tea intake was associated with slight reductions in fecundability among females, and caffeinated soda and energy drink intake were associated with reduced fecundability among males.

Successive time to pregnancy among women experiencing pregnancy loss

STUDY QUESTION

Is time to pregnancy (TTP) similar across successive pregnancy attempts among women experiencing pregnancy loss?

SUMMARY ANSWER

TTP after a loss may be longer compared with TTP before a loss.

WHAT IS KNOWN ALREADY

Two pregnancy cohort studies have reported that TTP is similar across pregnancy attempts in fertile women. However, this has not been investigated among women experiencing pregnancy losses.

STUDY DESIGN, SIZE, DURATION

Data for this analysis come from the Longitudinal Investigation of Fertility and the Environment Study, a population-based, preconception cohort of couples attempting pregnancy. During 2005-2009, recruitment was targeted to 16 counties in Michigan and Texas with reported exposures to persistent environmental chemicals. A total of 501 couples were recruited and followed for up to 12 months of pregnancy attempts allowing for continued participation of women with pregnancy losses until censoring.

PARTICIPANTS, SETTING, METHODS

We assessed TTP among 70 couples recruited upon discontinuing contraception for purposes of becoming pregnant and experiencing ≥1 prospectively observed pregnancy losses during 12 months of trying. There were 61 couples who contributed two pregnancy attempts and 9 who contributed three. Women were instructed in the use of urine-based home fertility monitors to time intercourse relative to ovulation and recorded their bleeding patterns in daily journals. TTP was defined as the number of menstrual cycles taken to achieve pregnancy. Women were also instructed in the use of home digital pregnancy tests and asked to begin pregnancy testing on the day of expected menses. Women recorded the results of their pregnancy tests in a daily journal with a single positive pregnancy test result indicating an hCG-confirmed pregnancy. Pregnancy losses were ascertained from a subsequent recorded negative pregnancy test or clinically confirmed loss. We estimated fecundability odds ratios (FORs) comparing subsequent to first TTP using discrete Cox models with robust standard errors, accounting for cycles off contraception before study entry and adjusting for maternal age, body mass index, reproductive history and time-varying cigarette, alcohol and caffeine usage while trying.

MAIN RESULTS AND THE ROLE OF CHANCE

The mean female age was 30.3 ± 4.3 years; 21% had a prior pregnancy loss before study entry. Of the second and third attempts, 59 and 43%, respectively, were longer compared with the first attempt. FORs <1 suggest reduced fecundability or a longer TTP when comparing the second with the first attempt (0.42, 95% confidence interval (CI): 0.28, 0.65), and similarly for the third relative to the first attempt (0.64, 95% CI: 0.18, 2.36). TTP in the second attempt was a median of 1 cycle longer (interquartile range: 0, 3 cycles) compared with TTP in the first attempt.

LIMITATIONS, REASONS FOR CAUTION

As this is the first study to investigate successive TTP exclusively among women experiencing pregnancy loss, our findings await corroboration since most losses occurred early in gestation. As such, the generalizability of our findings for all pregnancy losses awaits further research. We also had limited power to detect a reduction in fecundability for the third compared with first pregnancy attempt.

WIDER IMPLICATIONS OF THE FINDINGS

Unlike fertile women, TTP in women experiencing early pregnancy losses may trend towards longer subsequent attempts. If the findings are corroborated, women experiencing losses may benefit from counselling regarding trying times.

STUDY FUNDING/COMPETING INTERESTS

This research was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (contracts N01-HD-3-3355, N01-HD-3-3356 and NOH-HD-3-3358). K.J.S. was supported by an Intramural Research Training Award from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Division of Intramural Population Health Research. The authors have no conflicts of interest to declare.

The office visit

This article summarizes the current office-based evaluation of male infertility and offers speculation, based on current research, on the future evolution of this encounter. A comprehensive history, physical examination, and semen analysis remain paramount to directing the evaluation; however, new advances continue to refine diagnostic and treatment algorithms. Interpretation of the routine semen analysis as well as adjunctive assessments, including reactive oxygen species, DNA fragmentation, and fluorescent in situ hybridization (FISH) are discussed. The analysis of genetic and endocrine abnormalities is reviewed.

Caffeinated beverage and soda consumption and time to pregnancy

BACKGROUND

Many epidemiologic studies have evaluated the association between caffeine and fertility, with inconsistent results. Some studies suggest that various caffeine-containing beverages may affect fertility differently.

METHODS

We evaluated the relation of caffeine, coffee, tea, and sodas with time to pregnancy in a prospective cohort study of 3628 women planning a pregnancy, in Denmark (2007-2010). Women reported beverage intake at baseline and every 8 weeks during follow-up until they became pregnant or for up to 12 cycles. We used discrete-time Cox proportional hazards regression to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), controlling for potential confounders.

RESULTS

There was little relation between fecundability and caffeine intake of 300+ mg/day compared with < 100 mg/day (FR = 1.04 [95% CI = 0.90-1.21]) or coffee intake of 3+ servings/day compared with none (1.05 [0.85-1.33]). Soda consumption was associated with reduced fecundability: for all types of sodas combined, the adjusted FRs were 0.89 (0.80-0.98), 0.85 (0.71-1.02), 0.84 (0.57-1.25), and 0.48 (0.21-1.13) for < 1, 1, 2, and 3+ servings per day, respectively, compared with none. Tea drinking was associated with a slight increase in fecundability, with FR = 1.27 (0.98-1.64) for 2+ servings/day versus none.

CONCLUSION

In this prospective study of time to pregnancy, the association between caffeine intake and fertility differed by beverage type. Although we controlled for many confounders, our findings of reduced fecundability among soda drinkers and increased fecundability among tea drinkers could have resulted from confounding by unmeasured lifestyle characteristics.

Coffee and Smoking as Risk Factors of Twin Pregnancies: The Danish National Birth Cohort

Twinning rates have changed substantially over time for reasons that are only partly known. In this study we studied smoking, coffee and alcohol intake, and their possible interaction with obesity as potential determinants of twinning rates using data from the Danish National Birth Cohort between 1996 and 2002. We identified 82,985 pregnancies: 81,954 singleton and 1031 twins. For the twins we had data to classify 121 as monozygotic, 189 dizygotic (same sex), 313 dizygotic (opposite sex) but, 408 were of the same sex but with unknown zygosity. All mothers were interviewed about their prepregnancy weight and height, coffee and alcohol intake, smoking habits, and potential confounding factors at early stages of pregnancy. We identified smoking (> 10 cigarettes/day) as a possible determinant of twinning, particularly for dizygotic twinning rates (same sex) and furthermore corroborated that obesity and the mother's age are strong correlates of twinning. Others have found coffee intake to increase twinning rates but that is not seen in these data.

Predictors of pregnancy and live birth after insemination in couples with unexplained or male-factor infertility

OBJECTIVE

To identify risk factors for pregnancy outcomes in couples treated with intracervical or intrauterine insemination, with or without superovulation for unexplained or male-factor infertility.

DESIGN

Secondary analysis of data from a randomized superovulation and intrauterine insemination trial.

SETTING

Academic medical centers.

INTERVENTION(S)

Treatment continued for four cycles unless pregnancy was achieved.

PATIENT(S)

Out of 932 couples randomized to four treatment groups, 664 couples who had completed the lifestyle questionnaires were assessed for occurrence of pregnancy and live birth.

MAIN OUTCOME MEASURE(S)

Pregnancy and live birth.

RESULT(S)

The pregnancy and live birth rates were significantly higher in couples in which the female partners reported that they had consumed coffee or tea in the past or drank alcoholic beverages in the past (past users) compared with those who had never consumed coffee, tea, or alcoholic beverages. Past users also had significantly higher pregnancy and live birth rates than those currently consuming coffee or tea or alcoholic beverages. Demographic, occupational exposure, and other lifestyle factors were not significant.

CONCLUSION(S)

Couples in which the female partners drank coffee, tea, or alcoholic beverages in the past had higher pregnancy and live birth rates compared with never or current users. When discontinuing these habits, they might have made other lifestyle changes to improve the pregnancy outcome.

Effect of maternal coffee, smoking and drinking behavior on adult son's semen quality: prospective evidence from the Child Health and Development Studies

Fetal exposure to caffeine is associated with adverse pregnancy outcomes. Animal and human studies suggest that caffeine may have effects on the developing reproductive system. Here we report on mothers' smoking, coffee and alcohol use, recorded during pregnancy, and semen quality in sons in the age group of 38-47 years. Subjects were a subset of the Child Health and Development Studies, a pregnancy cohort enrolled between 1959 and 1967 in the Kaiser Foundation Health Plan near Oakland, California. In 2005, adult sons participated in a follow-up study (n = 338) and semen samples were donated by 196 participants. Samples were analyzed for sperm concentration, motility and morphology according to the National Cooperative Reproductive Medicine Network (Fertile Male Study) Protocol. Mean sperm concentration was reduced by approximately 16 million sperms for sons with high prenatal exposure (5 cups of maternal coffee use per day) compared with unexposed sons (P-value for decreasing trend = 0.09), which translates to a proportionate reduction of 25%. Mean percent motile sperm decreased by approximately 7 points (P-value = 0.04), a proportionate decline of 13%, and mean percent sperm with normal morphology decreased by approximately 2 points (P-value = 0.01), a proportionate decline of 25%. Maternal cigarette and alcohol use were not associated with son's semen quality. Adjusting for son's contemporary coffee, alcohol and cigarette use did not explain the maternal associations. Findings for son's coffee intake and father's prenatal coffee, cigarette and alcohol use were non-significant and inconclusive. These results contribute to the evidence that maternal coffee use during pregnancy may impair the reproductive development of the male fetus.

Food intake and social habits in male patients and its relationship to intracytoplasmic sperm injection outcomes

OBJECTIVE

To investigate the influence of the male partner's lifestyle, including eating and social habits, on semen quality and intracytoplasmic sperm injection (ICSI) success.

DESIGN

Observational study.

SETTING

Private fertility clinic.

PATIENT(S)

Two hundred fifty male patients undergoing ICSI cycles.

INTERVENTION(S)

We recorded dietary and social habits using a food frequency questionnaire adapted to meet specific study objectives. Evaluation of semen parameters and ICSI outcomes were performed.

MAIN OUTCOME MEASURE(S)

Frequency of intake of food items and social habits were registered on a scale with five categories ranging from no consumption to repeated daily consumption.

RESULT(S)

The sperm concentration was negatively influenced by body mass index (BMI) and alcohol consumption and was positively influenced by cereal consumption and the number of meals per day. The sperm motility was also negatively influenced by BMI, alcohol consumption, and smoking habit, whereas it was positively influenced by the consumption of fruits and cereals. The consumption of alcohol had a negative influence on the fertilization rate. The consumption of red meat as well as being on a weight loss diet had a negative impact on the implantation rate. In addition, the consumption of red meat and being on a weight loss diet had an effect on the pregnancy chance.

CONCLUSION(S)

Couples seeking assisted reproduction treatments must be advised about the drastic effect of both the male and female lifestyle on treatment success.

Inhibitory effect of caffeine on pacemaker activity in the oviduct is mediated by cAMP-regulated conductances

BACKGROUND AND PURPOSE

Spontaneous electrical activity, termed slow waves, drives rhythmic, propulsive contractions in the smooth muscle of the oviduct (myosalpinx). Myosalpinx contractions cause egg transport through the oviduct. Agents that disrupt slow wave pacemaker activity will therefore disrupt myosalpinx contractions and egg transport. Caffeine is commonly used as a ryanodine receptor agonist and has been previously associated with delayed conception. Here we assessed the effects of caffeine on pacemaker activity in the murine myosalpinx.

EXPERIMENTAL APPROACH

The effects of caffeine on electrical pacemaker activity were studied using intracellular microelectrode and isometric force measurements on intact oviduct muscle preparations. Responses to caffeine were compared with responses caused by 3-isobutyl-1-methylxanthine (IBMX) and forskolin.

KEY RESULTS

Caffeine caused hyperpolarization of membrane potential and inhibited slow wave generation and myosalpinx contractions. The effects of caffeine could be mimicked by the K(ATP) channel agonist pinacidil and antagonized by the K(ATP) channel antagonist glibenclamide. Caffeine is known to inhibit cyclic nucleotide phosphodiesterases (PDEs), leading to an increase in cytosolic cAMP and stimulation of downstream cAMP-dependent mechanisms. The effects of caffeine were mimicked by the PDE inhibitor, IBMX, and the adenylyl cyclase activator forskolin. These effects were also reversed by glibenclamide.

CONCLUSIONS AND IMPLICATIONS

These results suggest that caffeine activates K(ATP) channels in oviduct myosalpinx. Since caffeine abolishes slow waves and associated contractions of the myosalpinx, it would have a negative effect on egg transport through the oviduct and may contribute to the documented delayed conception in women consuming caffeinated beverages.

Working conditions associated with ovarian cycle in a medical center nurses: a Taiwan study

AIM

Decreased basal body temperature measurements predict ovulation with an accuracy of 74%. The anovulatory cycle exhibits an ovarian monophasic pattern. This study evaluated the relationship between ovarian cycle pattern and sociodemographic characteristics, menstrual history and work characteristics of nurses in a Taiwan medical center.

METHODS

Of 200 nurses recruited, 151 were analyzed. Each subject completed questionnaires and provided life recordings and daily basal body temperature measurements during the 14-week study.

RESULTS

The analytical results demonstrated that work place (P = 0.014) and work shift (P = 0.048) are significantly related to ovarian cycle pattern. Nurses who worked in emergent care units and wards had a higher prevalence of irregular ovarian cycle pattern. Approximately 53% of nurses who worked rotating shifts exhibited irregular ovarian cycle pattern.

CONCLUSIONS

Nurses who either had rotating shift work or worked in emergent care units and wards should be concerned with their own ovarian cycle pattern for their health.

Women's lifestyle behaviors while trying to become pregnant: evidence supporting preconception guidance

OBJECTIVE

We sought to prospectively measure women's daily cigarette, alcohol, and caffeine use, while attempting pregnancy in relation to intentions to change.

STUDY DESIGN

This was a cohort comprising 90 women enrolled upon discontinuing contraception and followed up prospectively until pregnant. Women reported number of daily cigarettes, and alcoholic and caffeinated beverages for 459 menstrual cycles while attempting pregnancy.

RESULTS

A significant mean reduction in daily caffeinated drinks (estimate [EST] = -0.52; 95% confidence interval [CI], -0.70 to -0.33) was observed when compared to baseline usage. Intention to change was associated with a reduction in caffeinated drinks (EST = -0.32; 95% CI, -0.64 to 0.00), and with alcohol and cigarette usage from the first menstrual cycle (EST = -0.15; 95% CI, -0.28 to -0.02 and EST = -1.65; 95% CI, -3.12 to -0.19, respectively).

CONCLUSION

A reduction in daily caffeine intake while attempting pregnancy was observed, but not in alcohol or cigarette use, underscoring the need for preconception guidance.

[Informations for the infertile couple]

The aim of the first consultation related to infertility is supposed to be the optimization of all factors that can increase the chances of pregnancy: more frequent sexual intercourse during the fertility windows; lifestyle modifications (better diet, decreased exposure to tobacco or other toxics); older couples can enjoy the same advice but should be proposed a quicker medical support. Maternal preconceptional advice must be transmitted. A testicular cancer must always be excluded in infertile men, while the risk of hormone-dependent cancers in infertile women remains undetermined. With the results of this first consultation, couples will generally be proposed the best solution to achieve their parental project: ovarian stimulation assisted reproductive technology (IUI, IVF or ICSI) or adoption.

Alcohol, drugs, caffeine, tobacco, and environmental contaminant exposure: reproductive health consequences and clinical implications

Reproductive function and fertility are thought to be compromised by behaviors such as cigarette smoking, substance abuse, and alcohol consumption; however, the strength of these associations are uncertain. Furthermore, the reproductive system is thought to be under attack from exposure to environmental contaminants, particularly those chemicals shown to affect endocrine homeostasis. The relationship between exposure to environmental contaminants and adverse effects on human reproductive health are frequently debated in the scientific literature and these controversies have spread into the lay press drawing increased public and regulatory attention. Therefore, the objective of the present review was to critically evaluate the literature concerning the relationship between lifestyle exposures and adverse effects on fertility as well as examining the evidence for a role of environmental contaminants in the purported decline of semen quality and the pathophysiology of subfertility, polycystic ovarian syndrome, and endometriosis. The authors conclude that whereas cigarette smoking is strongly associated with adverse reproductive outcomes, high-level exposures to other lifestyle factors are only weakly linked with negative fertility impacts. Finally, there is no compelling evidence that environmental contaminants, at concentrations representative of the levels measured in contemporary biomonitoring studies, have any effect, positive or negative, on reproductive health in the general population. Further research using prospective study designs with robust sample sizes are needed to evaluate testable hypotheses that address the relationship between exposure and adverse reproductive health effects.

Caffeine intake and semen quality in a population of 2,554 young Danish men

The authors examined the association between semen quality and caffeine intake among 2,554 young Danish men recruited when they were examined to determine their fitness for military service in 2001-2005. The men delivered a semen sample and answered a questionnaire including information about caffeine intake from various sources, from which total caffeine intake was calculated. Moderate caffeine and cola intakes (101-800 mg/day and < or =14 0.5-L bottles of cola/week) compared with low intake (< or =100 mg/day, no cola intake) were not associated with semen quality. High cola (>14 0.5-L bottles/week) and/or caffeine (>800 mg/day) intake was associated with reduced sperm concentration and total sperm count, although only significant for cola. High-intake cola drinkers had an adjusted sperm concentration and total sperm count of 40 mill/mL (95% confidence interval (CI): 32, 51) and 121 mill (95% CI: 92, 160), respectively, compared with 56 mill/mL (95% CI: 50, 64) and 181 mill (95% CI: 156, 210) in non-cola-drinkers, which could not be attributed to the caffeine they consumed because it was <140 mg/day. Therefore, the authors cannot exclude the possibility of a threshold above which cola, and possibly caffeine, negatively affects semen quality. Alternatively, the less healthy lifestyle of these men may explain these findings.

Caffeine use in children: what we know, what we have left to learn, and why we should worry

Caffeine is a widely used psychoactive substance in both adults and children that is legal, easy to obtain, and socially acceptable to consume. Although once relatively restricted to use among adults, caffeine-containing drinks are now consumed regularly by children. In addition, some caffeine-containing beverages are specifically marketed to children as young as 4 years of age. Unfortunately, our knowledge of the effects of caffeine use on behavior and physiology of children remains understudied and poorly understood. The purpose of this article is to review what is known about caffeine use in children and adolescents, to discuss why children and adolescents may be particularly vulnerable to the negative effects of caffeine, and to propose how caffeine consumption within this population may potentiate the rewarding properties of other substances. The following topics are reviewed: (1) tolerance and addiction to caffeine, (2) sensitization and cross-sensitization to the effects of caffeine, (3) caffeine self-administration and reinforcing value, and (4) conditioning of preferences for caffeine-containing beverages in both adults and children.

Validity of self-reported time to pregnancy

BACKGROUND

The reliability of retrospective time to pregnancy (TTP) has been established, but its validity has been assessed in only 1 study, which had a short follow-up.

METHODS

Ninety-nine women enrolled a decade earlier in a prospective TTP study were queried by means of mailed questionnaires about the duration of time they had required to become pregnant. Their responses were compared with their earlier data from daily diaries (gold standard).

RESULTS

One-third of women could not recall their earlier TTP either in menstrual cycles or calendar months. Only 17%-19% of women recalled their TTP exactly. Agreement increased to 41%-51%, 65%-72%, and 72%-77% when defined as +/-1, +/-2, and +/-3 months, respectively. Women with longer observed TTPs or previous pregnancies were more likely to under-report their TTP.

CONCLUSIONS

The findings raise questions about the commonly assumed validity of self-reported TTP. Recalled TTP may introduce error when estimating fecundability or classifying couples' fecundity status.

Caffeinated and alcoholic beverage intake in relation to ovulatory disorder infertility

BACKGROUND

Many studies have examined whether caffeine, alcohol, or specific beverages containing these substances affect fertility in women. However, most of these studies have retrospectively collected information on alcohol and caffeine intake, making the results susceptible to biases.

METHODS

We followed 18,555 married women without a history of infertility for 8 years as they attempted to become (or became) pregnant. Diet was measured twice during this period and prospectively related to the incidence of ovulatory disorder infertility.

RESULTS

There were 438 incident report of ovulatory disorder infertility during follow-up. Intakes of alcohol and caffeine were unrelated to the risk of ovulatory disorder infertility. Comparing the highest to lowest categories of intake, the multivariate-adjusted relative risk, was 1.11 (95% confidence interval = 0.76-1.64; P for trend 0.78) for alcohol and 0.86 (0.61-1.20; 0.44) for total caffeine. However, intake of caffeinated soft drinks was positively related to ovulatory disorder infertility. Comparing the highest to lowest categories of caffeinated soft drink consumption, the RR was 1.47 (1.09-1.98; 0.01). Similar associations were observed for noncaffeinated, sugared, diet, and total soft drinks.

CONCLUSIONS

Our findings do not support the hypothesis that alcohol and caffeine impair ovulation to the point of decreasing fertility. The association between soft drinks and ovulatory disorder infertility seems not to be attributable to their caffeine or sugar content, and deserves further investigation.

Semen quality according to prenatal coffee and present caffeine exposure: two decades of follow-up of a pregnancy cohort

BACKGROUND

A few studies have investigated the association between male caffeine consumption in adult life and semen quality with conflicting results, but so far no studies have explored the effect of prenatal coffee exposure. We studied the association between prenatal coffee and current caffeine exposure and semen quality and levels of reproductive hormones.

METHODS

From a Danish pregnancy cohort established in 1984-1987, 347 sons out of 5109 were selected for a follow-up study conducted 2005-2006. Semen and blood samples were analyzed for conventional semen characteristics and reproductive hormones and were related to information on maternal coffee consumption during pregnancy and present caffeine consumption. Data were available for 343 men.

RESULTS

There was a tendency toward decreasing crude median semen volume (P = 0.06) and adjusted mean testosterone (P = 0.06) and inhibin B (P = 0.09) concentrations with increasing maternal coffee consumption during pregnancy. Sons of mothers drinking 4-7 cups/day had lower testosterone levels than sons of mothers drinking 0-3 cups/day (P = 0.04). Current male caffeine intake was associated with increasing testosterone levels (P = 0.007). Men with a high caffeine intake had approximately 14% higher concentration of testosterone than those with a low caffeine intake (P = 0.008).

CONCLUSIONS

The results observed in this study are only tentative, but they do not exclude a small to moderate effect of prenatal coffee exposure on semen volume and levels of reproductive hormones. Present adult caffeine intake did not show any clear associations with semen quality, but high caffeine intake was associated with a higher testosterone concentration.

Periconception window: advising the pregnancy-planning couple

OBJECTIVE

To discuss the importance of the periconceptional window with regard to being a critical window of exposure. To review the empirical data related to healthy periconceptional behaviors.

DESIGN

Literature review.

CONCLUSION(S)

Human reproduction is a couple-dependent process. Recent literature has highlighted that the periconceptional time period is a critical window of exposure that can impact growth and development. In advising the pregnancy-planning couple, it is of paramount importance that couples have knowledge of the timing of the fertile window to ensure that intercourse occurs on days with the maximum probability of pregnancy. Many women adopt healthier lifestyles while trying to conceive, often quitting smoking, eating healthier or taking vitamins. However, there is a lack of empirical data from prospective studies regarding which environmental exposures or behaviors are or are not safe. Noticeably absent are data regarding the effect of male partners' exposures or behaviors on couple fecundity and fertility. As we improve our ability to pinpoint the timing of conception, we should be able to better advise couples planning pregnancy.