Smoking and female infertility: a systematic review and meta-analysis

Alcohol, cigarette smoking, and ovarian reserve in reproductive-age African-American women

BACKGROUND

Although alcohol consumption and cigarette smoking are common behaviors in reproductive-age women, little is known about the impact of consumption patterns on ovarian reserve. Even less is known about the effects of smoking and alcohol use in reproductive-age African-American women.

OBJECTIVE

The objective of the study was to examine the impact of the patterns of alcohol intake and cigarette smoking on anti-Müllerian hormone levels as a marker of ovarian reserve in African-American women.

STUDY DESIGN

This was a cross-sectional analysis from the baseline clinical visit and data collection of the Study of Environment, Lifestyle, and Fibroids performed by the National Institute of Environmental Health Sciences. A total of 1654 volunteers, aged 23-34 years, recruited from the Detroit, Michigan community completed questionnaires on alcohol intake and cigarette smoking and provided serum for anti-Müllerian hormone measurement. Multivariable linear and logistic regressions were used as appropriate to estimate the effect of a range of exposure patterns on anti-Müllerian hormone levels while adjusting for potential confounders including age, body mass index, and hormonal contraception.

RESULTS

Most participants were alcohol drinkers (74%). Of those, the majority (74%) engaged in binge drinking at least once in the last year. Women who reported binge drinking twice weekly or more had 26% lower anti-Müllerian hormone levels compared with current drinkers who never binged (95% confidence interval, -44, -2, P < .04). Other alcohol consumption patterns (both past and current) were unrelated to anti-Müllerian hormone. The minority of participants currently (19%) or formerly (7%) smoked, and only 4% of current smokers used a pack a day or more. Neither smoking status nor second-hand smoke exposure in utero, childhood, or adulthood was associated with anti-Müllerian hormone levels.

CONCLUSION

Results suggest that current, frequent binge drinking may have an adverse impact on ovarian reserve. Other drinking and smoking exposures were not associated with anti-Müllerian hormone in this cohort of healthy, young, African-American women. A longitudinal study of how these common lifestyle behaviors have an impact on the variability in age-adjusted anti-Müllerian hormone levels is merited.

Impact of smoking on fertility and age of menopause: a population-based assessment

BACKGROUND AND AIMS

Studies in patients seeking medically assisted reproduction have shown that smoking reduces fertility, but little information is available in the general population. We assessed the associations between smoking and the number of children, childbearing planning and age at menopause in a representative sample of the population of Lausanne, Switzerland.

METHODS

Data from 6711 participants (3530 women, age range 35-75 years) collected between 2003 and 2006 and again in 2009 and 2012. Smoking status, number of offsprings and age of menopause were assessed.

RESULTS

Women who currently smoke had significantly less children than former or never smokers: the number of children per women (average±SD) was 1.38±1.05, 1.45±1.07 and 1.576±1.16, respectively (p<0.001). Women who currently smoke had their first child at an earlier age than the others: 26.7±5.2, 27.4±5.4 and 26.9±5.2 years old for current, former and never smokers, respectively, (p=0.01). Similar findings were found for men: number of children per men 1.475±1.16, 1.67±1.13 and 1.55±1.22 for current, former and never smokers, respectively (p<0.001); no difference was found regarding age at the first child. The difference persisted after multivariate adjustment (adjusted for age, body mass index, Caucasian origins, alcohol consumption, caffeinated drinks consumption, educational level, receiving social help and women taking contraceptives) for the age at first child among women. No association was found between Heaviness of Smoking Index and the number of children among current smokers in both genders. Women who smoke had their menopause more than 1 year prior than never-smoking women (48.9±0.2 years compared with 47.8±0.3 years, respectively, p=0.002).

CONCLUSIONS

Smoking is associated with an earlier age of having the first child and of menopause among women.

Female exposure to phthalates and time to pregnancy: a first pregnancy planner study

STUDY QUESTION

Is female exposure to phthalate metabolites associated with reduced fecundity, as estimated by prolonged time to pregnancy (TTP)?

SUMMARY ANSWER

Female exposure to monoethyl phthalate (MEP) but not monobutyl phthalate (MBP), monobenzyl phthalate (MBzP) and monoethylhexyl phthalate (MEHP) was associated with a longer TTP.

WHAT IS KNOWN ALREADY

Male exposure to phthalates is potentially associated with adverse effects on human fecundity in epidemiological studies, but little is known about the potential effects on female reproduction.

STUDY DESIGN SIZE AND DURATION

A cohort study with prospective data based on 229 women from a Danish cohort of 430 first pregnancy planning couples enrolled in 1992-1994. In 2009, urinary analyses of phthalate metabolites were performed on stored urine samples from this cohort.

PARTICIPANTS/MATERIALS, SETTING AND METHODS

We analyzed MEP, MBP, MBzP and MEHP in female morning spot urine samples collected daily during the first 10 days of menstrual cycles after discontinuation of contraception. The exposure assessment was based on the mean of two measurements from each woman collected in a period of 6 menstrual cycles. We used Cox regression with discrete time to estimate fecundability ratios (FRs) and 95% CI in relation to the average urine metabolite concentration exposure level, controlled for age and BMI, and the time-varying variables smoking and alcohol.

MAIN RESULT AND ROLE OF CHANCE

Urinary concentration of MEP was associated with a decreased fecundity (adjusted FR 0.79; 95% CI: 0.63; 0.99) corresponding to a 21% decreased probability of conception for each natural log (ln) unit increase in MEP. No significant association with TTP was found for MBP, MBzP and MEHP.

LIMITATIONS REASONS FOR CAUTION

Subfertile women were overrepresented in the study population due to exclusion of 77 high fertile women who became pregnant in the first cycle when urine collection began.

WIDER IMPLICATIONS OF THE FINDINGS

Our results suggest that female exposure to MEP may have an adverse effect on female fecundity, but these findings need to be replicated in a larger and newer cohort study with sufficient exposure contrast if the use of diethyl phthalate (DEP) and thereby MEP in the future potentially should be regulated in cosmetics and industrial consumer products.

STUDY FUNDING/COMPETING INTERESTS

The original data collected were founded by Aarhus University Research Foundation, the Danish Medical Research Council and the Danish Medical Health Insurance Foundation. There are no conflicts of interest to be declared.

TRIAL REGISTRATION NUMBER

N/A.

Fossum G, Gracia C, La Barbera A, Mersereau J, Odem R, Paulson R, Penzias A, Pisarska M, Rebar R, Reindollar R, Rosen M, Sandlow J, Vernon M. Optimizing natural fertility: a committee opinion

This Committee Opinion provides practitioners with suggestions for optimizing the likelihood of achieving pregnancy in couples/individuals attempting conception who have no evidence of infertility. This document replaces the document of the same name previously published in 2013, Fertil Steril 2013;100(3):631-7.

Lifestyle and in vitro fertilization: what do patients believe?

Background

Patients have many beliefs regarding lifestyle factors and IVF outcomes.

Methods

Observational study of 208 IVF patients at an academic infertility center. Main outcome measures were perceived influence of various lifestyle factors assessed by multivariable logistic regression and p-value tests for linear trend (P_t).

Results

A majority of participants believed that there were many women’s lifestyle choices that were influential, compared to fewer male factors (cessation of tobacco (72 %), alcohol (69 %), caffeine (62 %), and use of vitamins (88 %)). Compared to participants with less education, participants with a higher education level were less likely to believe vitamins were helpful and some alcohol use was not harmful. As income decreased, participants were less likely to consider dietary factors contributory to IVF success, such as women (p-trend, p = 0.02) and men (p-trend, p = 0.009) consuming a full-fat dairy diet. Participants’ beliefs were most commonly influenced by physicians (84 %) and the internet (71 %).

Conclusions

Patients believed many lifestyle factors are associated with IVF success. Understanding patients’ assumptions regarding the effect of lifestyle factors on IVF success may better allow physicians to counsel patients about IVF outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s40738-016-0026-5) contains supplementary material, which is available to authorized users.

Exploring Infertility from the Cultural Context of Latino College Students: Results from a Preliminary Focus Group

Despite a racial/ethnic disparity, little research has examined minority group perceptions of infertility. After developing a 15-question English-language focus group guide, 13 Latino college students (ages 19-22) at a Midwestern university were recruited to participate in a focus group to discuss their perceptions of infertility in the context of their family and culture. The focus group was audio recorded, professionally transcribed, and analyzed according to the constructed Grounded Theory approach. Three major themes were identified: 1) infertility is not considered when looking towards the future; 2) infertility is not discussed due to shame; and 3) infertility does not require a medical resolution. College students have the opportunity to make lifestyle modifications that can optimize fertility, but intention to change behavior is contingent on accurate fertility knowledge, which is often influenced by cultural norms. Our results suggest that these Latino students do not consider infertility a risk in their future lives nor is infertility something they consider should be explicitly discussed. Importantly, they do not perceive the need for medical interventions when addressing infertility, which carries implications for treatment seeking. When creating educational interventions for infertility, it is important to take into account the cultural lens through which infertility is understood.

Factors which Determine the Age of the Menopause

Menopause is the final cessation of menstruation. Humans are the only primates to experience a menopause, and its origins and purpose remain unclear. The age of menopause has remained constant since Aristotle, although the age of menarche has fallen in the past 100 years. The incidence of natural premature ovarian failure before age 40 is 1%. The factors controlling the timing of the menopause are not well understood. The possession of two X chromosomes is essential for normal ovarian function. Genetic, reproductive and lifestyle factors, chemotherapy and radiation, pelvic surgery, infection, and autoimmunity have all been implicated. There is an association between age of menopause of mothers and daughters and greater concordance with identical than non-identical twins. However, with the exception of smoking which advances menopause by two years, these factors have failed to show a consistent influence on age at menopause.

Do subfertile women adjust their habits when trying to conceive?

AIM

The aim of this study was to investigate lifestyle habits and lifestyle adjustments among subfertile women trying to conceive.

MATERIALS AND METHODS

Women (n = 747) were recruited consecutively at their first visit to fertility clinics in mid-Sweden. Participants completed a questionnaire. Data were analyzed using logistic regression, t tests, and chi-square tests.

RESULTS

The response rate was 62% (n = 466). Mean duration of infertility was 1.9 years. During this time 13.2% used tobacco daily, 13.6% drank more than three cups of coffee per day, and 11.6% consumed more than two glasses of alcohol weekly. In this sample, 23.9% of the women were overweight (body mass index, BMI 25-29.9 kg/m(2)), and 12.5% were obese (BMI ≥30 kg/m(2)). Obese women exercised more and changed to healthy diets more frequently than normal-weight women (odds ratio 7.43; 95% confidence interval 3.7-14.9). Six out of ten women (n = 266) took folic acid when they started trying to conceive, but 11% stopped taking folic acid after some time. Taking folic acid was associated with a higher level of education (p < 0.001).

CONCLUSIONS

Among subfertile women, one-third were overweight or obese, and some had other lifestyle factors with known adverse effects on fertility such as use of tobacco. Overweight and obese women adjusted their habits but did not reduce their body mass index. Women of fertile age would benefit from preconception counseling, and the treatment of infertility should routinely offer interventions for lifestyle changes.

Natrelle Silicone Breast Implant Follow-Up Study: Demographics, Lifestyle, and Surgical Characteristics of More Than 50,000 Augmentation Subjects

Background:

A large, multicenter, 10-year observational study is being conducted to compare the long-term safety and effectiveness of Natrelle silicone breast implants with saline implants or national norms. Study baseline data and surgical characteristics are reported here.

Methods:

Women seeking primary augmentation, revision-augmentation, primary reconstruction, or revision-reconstruction participated. Eligible subjects had completed surgery and received one implant or matching implants. Baseline demographics, health, lifestyle, and surgical characteristics were recorded. Data are presented here for subjects (≥22 years old) who underwent primary augmentation or revision-augmentation.

Results:

Of 50,979 subjects who underwent augmentation procedures, 35,756 received silicone implants and 15,223 received saline implants. Of these, 86.3 percent underwent primary augmentation, and 13.7 percent underwent revision-augmentation; nearly all subjects (99.3 percent) received bilateral implants. In the primary augmentation group, 67.6 percent of subjects received silicone implants versus 86.1 percent in the revision-augmentation group. Median age was lower in the primary augmentation group compared with the revision-augmentation group (33 versus 42 years old, respectively). Most subjects were white nonsmokers and had attended college. Hispanic subjects and subjects with a body mass index of 25 kg/m² or greater were more likely to receive saline versus silicone implants. Across groups, the most common characteristics by procedure or implant type included inframammary incision site (54.6 percent), partial (58.2 percent) or complete (31.9 percent) submuscular placement, smooth surface implants (93.1 percent), and implant size of 300 to 399 cc. Incision size was larger for silicone versus saline implants.

Conclusion:

These data add to the body of knowledge on women undergoing augmentation procedures by providing an unprecedented look at a large number of subjects.

Adult air pollution exposure and risk of infertility in the Nurses' Health Study II

STUDY QUESTION

Is there an association between air pollution exposures and incident infertility?

SUMMARY ANSWER

Increased exposure to air pollution is associated with an increased incidence of infertility.

WHAT IS KNOWN ALREADY

Exposures to air pollution have been associated with lower conception and fertility rates. However, the impact of pollution on infertility incidence is unknown.

STUDY DESIGN, SIZE, DURATION

Prospective cohort study using data collected from 116 430 female nurses from September 1989 to December 2003 as part of the Nurses' Health Study II cohort.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Infertility was defined by report of attempted conception for ≥12 months without success. Participants were able to report if evaluation was sought and if so, offer multiple clinical indications for infertility. After exclusion, 36 294 members were included in the analysis. Proximity to major roadways and ambient exposures to particulate matter less than 10 microns (PM10), between 2.5 and 10 microns (PM2.5-10), and less than 2.5 microns (PM2.5) were determined for residential addresses for the 36 294 members between the years of 1993 and 2003. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using multivariable adjusted Cox proportional hazard models with time-varying covariates.

MAIN RESULTS AND THE ROLE OF CHANCE

Over 213 416 person-years, there were 2508 incident reports of infertility. Results for overall infertility were inconsistent across exposure types. We observed a small increased risk for those living closer to compared to farther from a major road, multivariable adjusted HR = 1.11 (CI: 1.02-1.20). This was consistent for those reporting primary or secondary infertility. For women living closer to compared to farther from a major road, for primary infertility HR = 1.05 (CI: 0.94-1.17), while for secondary infertility HR = 1.21 (CI: 1.07-1.36). In addition, the HR for every 10 µg/m(3) increase in cumulative PM2.5-10 among women with primary infertility was 1.10 (CI: 0.96-1.27), and similarly was 1.10 (CI: 0.94-1.28) for those with secondary infertility.

LIMITATIONS, REASONS FOR CAUTION

Within the 2 year window of infertility diagnosis, we do not have the exact date of diagnosis or the exact timing of the start of attempting conception. As infertility status and subtypes of infertility were prospectively collected biennially, we were unable to tightly examine the timing of exposures on incidence of infertility. In terms of exposure quantification, we used ambient air pollution exposures as a proxy for personal exposures, potentially leading to exposure misclassification. However, several studies suggest that ambient measurements are an acceptable surrogate for individual level exposures in most populations.

WIDER IMPLICATIONS OF THE FINDINGS

We observed an association between all size fractions of PM exposure, as well as traffic-related air pollution, and incidence of infertility. Of note, the strongest association was observed between cumulative average exposures over the course of follow-up and the risk of infertility, suggesting that chronic exposures may be of greater importance than short-term exposures.

STUDY FUNDING/COMPETING INTERESTS

The work for this paper was supported by the following: S.M.: Reproductive Scientist Development Program HD000849, and the Building Interdisciplinary Research Careers in Women's Health HD043444, the Boston University CTSI 1UL1TR001430, and a research grant from the Boston University Department of Obstetrics and Gynecology, S.A.M.: R01HD57210 from the National Institute of Child Health and Human Development and the Massachusetts Institute of Technology Center for Environmental Health Sciences Translational Pilot Project Program, R01CA50385 from the National Cancer Institute, J.E.H. and F.L.: 5R01ES017017 from the National Institute for Environmental Health Sciences, 5 P42 ES007381 from the National Institute of Environmental Health at the National Institute of Health. L.V.F.: T32HD060454 in reproductive, perinatal, and pediatric epidemiology from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The Nurses' Health Study II is additionally supported by infrastructure grant UM1CA176726 from the National Cancer Institute, NIH, U.S. Department of Health and Human Services. The authors have no actual or potential competing financial interests to disclose.

The prevalence of positive urinary cotinine tests in Korean infertile couples and the effect of smoking on assisted conception outcomes

OBJECTIVE

Smoking has been reported to harm nearly every organ of the body, but conflicting results have been reported regarding the effects of smoking on assisted conception. In this prospective cohort study, we aimed to investigate the prevalence of positive urinary cotinine tests in infertile couples and whether cotinine positivity was associated with infertility treatment outcomes.

METHODS

A qualitative urinary cotinine test was administered to 127 couples who underwent in vitro fertilization (IVF, n=92) or intrauterine insemination (IUI, n=35).

RESULTS

The overall prevalence of positive urinary cotinine test was 43.3% (55/127) in the male partners and 10.2% (13/127) in the female partners with similar prevalence rates in both genders in the IUI and IVF groups. Semen characteristics, serum markers of ovarian reserve, and number of retrieved oocytes were comparable among cotinine-positive and cotinine-negative men or women (with the exception of sperm count, which was higher among cotinine-positive men). The results of urinary cotinine tests in infertile couples were not associated with IVF and IUI outcomes.

CONCLUSION

The presence of cotinine in the system, as indicated by a positive urinary cotinine test, was not associated with poorer outcomes of infertility treatment.

Comparative Evaluation of the Impact of Subacute Exposure of Smokeless Tobacco and Tobacco Smoke on Rat Testis

This study investigated the effects of 30-day exposure to tobacco smoke (TS), smokeless tobacco (ST), and nicotine on reproductive parameters and oxidative biomarkers in prepubertal and adult male rats. Sperm motility was reduced by 77.5 and 89.0% in TS and ST exposed prepubertal rats and 71.1 and 86.4% in adult rats, respectively. Sperm count was also reduced by 64.7 and 89.9% in prepubertal rats and 64.9 and 47.0% in adult rats, respectively. Nicotine decreased sperm motility (82.2%) and count (62.6%) in prepubertal rats but caused no effect in adult rats. There were no changes in sperm morphology; testosterone was decreased, while LH and FSH were increased in exposed rats, when compared with control. Malondialdehyde levels in testes of exposed rats were increased, and GSH, SOD, and catalase were altered. Results indicate that subacute exposure of tobacco products alters sperm characteristics in a rank order of ST > TS > nicotine, which may be linked to increase in oxidative stress in the testis.

Knowledge and attitudes of adults towards smoking in pregnancy: results from the HealthStyles© 2008 survey

Smoking during pregnancy is causally associated with many adverse health outcomes. Quitting smoking, even late in pregnancy, improves some outcomes. Among adults in general and reproductive-aged women, we sought to understand knowledge and attitudes towards prenatal smoking and its effects on pregnancy outcomes. Using data from the 2008 HealthStyles© survey, we assessed knowledge and attitudes about prenatal smoking and smoking cessation. We classified respondents as having high knowledge if they gave ≥ 5 correct responses to six knowledge questions regarding the health effects of prenatal smoking. We calculated frequencies of correct responses to assess knowledge about prenatal smoking and estimated relative risk to examine knowledge by demographic and lifestyle factors. Only 15 % of all respondents and 23 % of reproductive-aged women had high knowledge of the adverse effects of prenatal smoking on pregnancy outcomes. Preterm birth and low birth weight were most often recognized as adverse outcomes associated with prenatal smoking. Nearly 70 % of reproductive-aged women smokers reported they would quit smoking if they became pregnant without any specific reasons from their doctor. Few respondents recognized the benefits of quitting smoking after the first trimester of pregnancy. Our results suggest that many women lack knowledge regarding the increased risks for adverse outcomes associated with prenatal smoking. Healthcare providers should follow the recommendations provided by the American Congress of Obstetricians and Gynecologists, which include educating women about the health risks of prenatal smoking and the benefits of quitting. Healthcare providers should emphasize quitting smoking even after the first trimester of pregnancy.

Preliminary study of blood methylmercury effects on reproductive hormones and relevant factors among infertile and pregnant women in Taiwan

Methylmercury (MeHg) is the most poisonous mercury species and an endocrine-disrupting chemical that could cause reproductive and developmental harm effects in animals. In this study, we recruited 310 infertile women and 57 pregnant women and investigated their blood MeHg levels. The distribution of blood reproductive hormone, selenium and zinc levels, and the difference of relevant factors by the reference level of blood MeHg (5.8 μg/L) of infertile women were further examined. Results showed that greater percentages of sashimi consumption, frequencies of Chinese herbal medicine use, alcohol consumption, and lack of physical activity were observed in infertile women than those for pregnant women. Blood MeHg concentration was significantly greater in infertile than that in pregnant women. Significant concentration differences for FSH and LH by the dichotomized reference level of blood MeHg (5.8 μg/L) in infertile women were not observed, which may stem from that these reproductive hormones in participated infertile women were mostly in the normal reference range. Consumption of fish and sashimi represented the major source of MeHg exposure in infertile women. MeHg levels were elevated in infertile women, and consistent with fish consumption frequency. Compared to the referent level of blood MeHg levels <5.8 μg/L, the elevated blood MeHg levels (⩾5.8 μg/L) in infertile women were 3.35 and 4.42 folds risk in categorized frequencies of fish consumption 1-2 meals per week and more than 3 meals per week, respectively. The obtained results provide evidences and help updating the advisory of fish consumption and improving women's reproductive health.

Infertility and miscarriage: common pathways in manifestation and management

The relationship between miscarriage and fertility is complex. While most healthcare settings treat miscarriage as a problem of subfertility in assisted reproduction units, others believe that miscarriage occurs in super-fertile women. Infertile women undergoing assisted reproduction are at a greater risk of having a miscarriage especially at an advanced age compared with women conceiving naturally. Aberrant expression of immunological factors and chromosomal abnormalities underlie both infertility and miscarriage. Common risk factors include increased maternal age, obesity, smoking, alcohol, pre-existing medical conditions and anatomical abnormalities of the reproductive system. Management pathways of both conditions may be similar with pre-implantation genetic testing and assisted reproductive technology used in both conditions. This paper discusses the synergies and differences between the two conditions in terms of their epidemiology, etiopathogenesis, risk factors and management strategies. The two conditions are related as degrees of severity of reproductive failure with common pathways in manifestation and management.

The impact of lifestyle modifications, diet, and vitamin supplementation on natural fertility

BACKGROUND

Infertility is a relatively common condition. When patients are confronted with this diagnosis, there are medical, psychological, and financial sequelae. Patients often wonder if there is anything they can do to optimize their natural fertility or increase the effectiveness of infertility treatments.

FINDINGS

If there is a clear impact on fertility, such as with smoking and alcohol, cessation should be advised. Similarly, weight loss should be recommended if the BMI is in the overweight and obese category, and weight gain should be recommended for an underweight BMI. The evidence surrounding other lifestyle modifications is less clear. There are conflicting data regarding an optimal fertility diet and consumption of vitamins and supplements. Antioxidants seem to improve semen parameters in men, but the effect on female fertility is less clear. If conflicting evidence exists, such as with caffeine consumption or exercise, moderation should be emphasized. Finally, the diagnosis of infertility and subsequent fertility treatments are stressful for both partners. The psychological aspects should not be ignored and methods such as yoga and cognitive behavioral therapy may be beneficial.

CONCLUSION

Continued research will determine the optimal lifestyle modifications to achieve pregnancy.

[Relationships between psychological well-being, lifestyle factors and fertility]

INTRODUCTION

10 to 15% of the Hungarian fertile age population struggles with reproductivity problems. Previous researches have shown that psychological well-being and lifestyle factors play a pivotal role in overall health status, which is closely related to fertility.

AIM

The aim of the study was to examine fertility-related psychological and lifestyle factors in a Hungarian sample.

METHOD

194 women (115 infertile and 79 fertile) took part in the study. Standardized, validated questionnaires were used for the assessment of psychological factors and self-administered questions were used for exploring lifestyle factors.

RESULTS

The results show that infertile women are younger (33.98±4.89 vs. 36.43±5.81 years, p<0.005) and their psychological status is significantly worse compared to their fertile counterparts. The number of their depressive (BDI 14.00±12.21 vs. 7.79±9.17, p<0.005) and anxiety symptoms is higher (STAI-T 48.53±10.56 vs. 40.25±10.65, p<0.005) compared to fertile women. Findings related to lifestyle factors show that lower level of fluid consumption (1.71±0.67 vs. 1.95±0.68, p<0.05) and diet (31.30% vs. 18.42%, p<0.05) is significantly related to infertility. In this sample higher level of fluid consumption was associated with the fertile group (OR = 1.65, CI = 2.58-1.06), independently of body mass index and age.

CONCLUSIONS

The results confirm the findings of international researches showing that women struggling with infertility are in worse psychological condition than their fertile counterparts. The authors conclude that the findings demand further investigations and follow-up studies in order to more specifically determine the relationship between fluid consumption and fertility.

Demographic factors associated with smoking cessation during pregnancy in New South Wales, Australia, 2000-2011

Background

Smoking during pregnancy increases the risk of adverse health outcomes for both the mother and the child. Rates of smoking during pregnancy, and rates of smoking cessation during pregnancy, vary between demographic groups. This study describes demographic factors associated with smoking cessation during pregnancy in New South Wales, Australia, and describes trends in smoking cessation in demographic subgroups over the period 2000 – 2011.

Methods

Data were obtained from the New South Wales Perinatal Data Collection, a population-based surveillance system covering all births in New South Wales. Multivariate logistic regression was used to explore associations between smoking cessation during pregnancy and demographic factors.

Results

Between 2000 and 2011, rates of smoking cessation in pregnancy increased from 4.0% to 25.2%. Demographic characteristics associated with lower rates of smoking cessation during pregnancy included being a teenage mother, being an Aboriginal person, and having a higher number of previous pregnancies.

Conclusions

Between 2000 and 2011, rates of smoking cessation during pregnancy increased dramatically across all demographic groups. However, specific demographic groups remain significantly less likely to quit smoking, suggesting a need for targeted efforts to promote smoking cessation in these groups.

Modifiable Risk Factors and Infertility: What are the Connections?

Infertility is a relatively common condition, greatly affecting couples medically and psychologically. Although infertility treatment is safe, it can be time-intensive, expensive and increase the risk of multiple gestations. Thus, to reduce costs and risks, couples may initially consider lifestyle change to increase their fertility and chances of pregnancy. For many of the diet factors studied (for example: caffeine, soy, protein, iron), there are conflicting data. However, there are some items men and women consume that are detrimental to fertility, such as alcohol and tobacco. The data on exercise are varied but may have an effect on ovulation and fertility - positive or negative. Body mass index appears to impact fertility also, with obesity in both men and women negatively affecting pregnancy rates. In addition, there remains concern and a growing body of research on environmental toxin exposures and reproductive health. Finally, supporting patients through infertility diagnosis and treatment is critical, as psychological stress may impact conception. It is imperative that the relationship between lifestyle factors and fertility continue to be explored as to lessen the morbidity associated with infertility.

Prevalence of maternal preconception risk factors: an Italian multicenter survey

Objectives

Adequate preconception maternal health care is essential to reduce the risk of unwanted pregnancy outcomes and complications. Still, many women are exposed to a number of unhealthy risk factors both before and early in pregnancy. This study aimed to estimate the prevalence of a number of important preconception risk factors using data from a recent multicenter study in Italy.

Methods

The study was based on cross-sectional data from seven maternity clinics located in six different regions in Italy during the period January – June, 2012. Data on maternal preconception risk factors and characteristics were collected from 1,892 women who delivered healthy children and 320 women who were pregnant in the first trimester.

Results

About 97% of the women (n = 2,212) were exposed to one or more preconception risk factors. The overall prevalence of the most essential maternal risk factors was as follows: 41% had a age ≥35 years, 36% mistimed or did not intend their pregnancy, 58% did not request a preconception health visit to their doctor, 76% did not use folic acid supplements before pregnancy, 26% smoked at the last menstrual period, 19% had a body mass index ≥25 kg/m² before pregnancy, and 10% suffered from pregestational chronic diseases. The prevalence of certain variables varied between the maternity clinics.

Conclusions

Many Italian women are exposed to a number of preconception risk factors that have been associated with adverse pregnancy complications and outcomes. More effective intervention programs to improve preconception health in Italian women are strongly needed.

The Low Prevalence of Y Chromosomal Microdeletions is Observed in the Oligozoospermic Men in the Area of Mato Grosso State and Amazonian Region of Brazilian Patients

OBJECTIVE

To determine the prevalence of chromosomal abnormalities and microdeletions on Y chromosome in infertile patients with oligozoospermia or azoospermia in Mato Grosso state, Brazil.

METHODS

This cross-sectional study enrolled 94 men from infertile couples. Karyotype analysis was performed by lymphocyte culture technique. DNA from each sample was extracted using non-enzymatic method. Microdeletions were investigated by polymerase chain reaction (PCR).

RESULTS

With the use of cytogenetic analysis, five patients (5.3%) had abnormal karyotype, one azoospermic patient (1.1%) had karyotype 46,XY,t(7;1) (qter-p35), one (1.1%) with mild oligozoospermia had karyotype 46,XY,delY(q), and two other azoospermic patients had karyotype 47,XXY, consistent with Klinefelter syndrome (KS). One of them (1.1%) with severe oligozoospermia had karyotype 46,XY,8p+. Microdeletion on Y chromosome was found in the azoospermia factor c (AZFc) region in only one azoospermic patient (1.1%).

CONCLUSIONS

The prevalence of genetic abnormalities in oligo/azoospermic Brazilian men from infertile couple was 5.3%, and microdeletion on Y chromosome was not a common finding in this population (1.1%).

Psychosocial determinants of cigarette smoking among university students in Jordan

The objectives of this study were to describe the prevalence of cigarette use and water pipe smoking in Jordanian university students and to analyze differences in determinants between cigarette smokers and non-smokers. A cross-sectional questionnaire was administered to a random sample of 400 students (18-24 years, 51% males). Smokers were compared with non-smokers on several smoking-related determinants. Data were analyzed using descriptive statistics, t-test, χ 2 test and binary logistic regression analysis. The prevalence rates of cigarette use and water pipe smoking were 25.9% and 23.3%, respectively. Cigarette smokers differed significantly from non-smokers on almost all of the assessed determinants. The I-Change model explained 85% of the total variance of cigarette-smoking behavior. Cigarette smoking was determined by being male and older, having more depressive symptoms, having less Muslim identity, being more emancipated, perceiving more pros of smoking, having more modeling from peers and having lower self-efficacy. The popularity of cigarette use and water pipe smoking among Jordanian students necessitates health promotion interventions that motivate students not to engage in smoking behaviors by clearly outlining the outcomes of smoking and the healthier alternatives, how to cope with social influences and difficult situations in order to increase self-efficacy.

The effects of cigarette smoke extract on ovulation, oocyte morphology and ovarian gene expression in mice

Cigarette smoking can harm fertility, but the existing research has targeted primarily on ovarian follicles, embryos or sex hormone. In this study, we tested cigarette smoke extract on ovulation, oocyte morphology and ovarian gene expression associated with inhibition of oxidative stress using C57BL/6 mice. Mice in the experimental group were administered a cigarette smoke extract (CSE) solution (2 mg/ml) orally daily, while the blank control group was given dimethylsulfoxide (DMSO). A positive control group (menadione) was used that received an intraperitoneal injection of 15 mg/kg menadione in oil solution daily. We found that the CSE group manifested a reduced diameter of zona pellucida-free oocyte (ZP-free OD) and a morphologically misshapen first polar body (PB). Our results suggest that CSE exposure is associated with a shrink size and poor quality of oocytes. Quitting smoking is a wise choice to ensure good fertility.

Urinary bisphenol A, phthalates, and couple fecundity: the Longitudinal Investigation of Fertility and the Environment (LIFE) Study

OBJECTIVE

To assess the relationship between environmental chemicals and couple fecundity or time to pregnancy (TTP).

DESIGN

Prospective cohort.

SETTING

Communities of targeted populations with reported exposure.

PATIENT(S)

501 couples recruited upon discontinuing contraception to become pregnant, 2005-2009.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) estimated for each partner's chemical concentrations adjusted for age, body mass index, cotinine, creatinine, and research site while accounting for time off contraception.

RESULT(S)

Couples completed interviews and anthropometric assessments and provided the urine specimens for quantification of bisphenol A (BPA) and 14 phthalate metabolites, which were measured using high-performance liquid chromatography with electrospray triple-quadrupole mass spectrometer. Women recorded menstruation and pregnancy test results in daily journals. Couples were evaluated until a positive human-chorionic gonadotropin pregnancy test or 12 cycles without pregnancy. Neither female nor male BPA concentration was associated with TTP (FOR 0.98; 95% CI, 0.86, 1.13 and FOR 1.04; 95% CI, 0.91, 1.18, respectively). Men's urinary concentrations of monomethyl, mono-n-butyl, and monobenzyl phthalates were associated with a longer TTP (FOR 0.80; 95% CI, 0.70, 0.93; FOR 0.82, 95% CI, 0.70, 0.97; and FOR 0.77, 95% CI, 0.65 0.92, respectively).

CONCLUSION(S)

Select male but not female phthalate exposures were associated with an approximately 20% reduction in fecundity, underscoring the importance of assessing both partners' exposure to minimize erroneous conclusions.

General aspects of fertility and infertility

Fertility rates have been declining in most Western nations over the past several decades, although it is not entirely clear if an increased rate of infertility substantially contributes to this. As compared to other species, the reproductive efficiency of humans is relatively low. Factors related to fertility include age, exposure to sexually transmitted diseases, frequency of intercourse, coital timing, as well as diet and lifestyle habits. Infertility is considered a disease due to its major disruption of major organ systems and life functions. An infertility evaluation is recommended after 12 months or more of regular, unprotected intercourse and may be considered after 6 months for those female patients over the age of 35 or with other known abnormalities. A proper infertility evaluation is a comprehensive examination of possibly identifiable infertility factors of both female and male partners, lending itself to the most appropriate and potentially effective treatment.

Healthcare expenses associated with multiple vs singleton pregnancies in the United States

OBJECTIVE

The purpose of this study was to document cost that is associated with multiple births vs singleton births in the United States.

STUDY DESIGN

This was a retrospective cohort study that used a claims database. Women 19-45 years old with live-born infants from 2005-2010 were identified. Infant deliveries were identified by International Classification of Diseases, 9th Revision, Clinical Modification diagnosis codes. The cost entailed all payment made by insurers and patients. For mothers, the cost included expenses from 27 weeks before delivery to 1 month after delivery. For infants, the cost contained all expenses until their first birthday. Adjusted cost was estimated by generalized linear models after adjustment for the potential confounding variables with a gamma distribution and a log link.

RESULTS

The analysis included 437,924 eligible deliveries. Of them, 97.02% were singletons; 2.85% were twins, and 0.13% was triplets or more. Women with multiple pregnancies had higher systemic and localized comorbidities compared with women with singleton pregnancies (P < .0001). Twins and triplets or more were more likely to have stayed in a neonatal intensive care unit than were singletons (P < .0001). On average, adjusted total all-cause health care cost was $21,458 (95% confidence interval [CI], $21,302-21,614) per delivery with singletons, $104,831 (95% CI, $103,402-106,280) with twins, and $407,199 (95% CI, $384,984-430,695) with triplets or more.

CONCLUSION

Pregnancies with the delivery of twins cost approximately 5 times as much when compared with singleton pregnancies; pregnancies with delivery of triplets or more cost nearly 20 times as much.

Cigarette smoking among female students in five medical and nonmedical colleges

Objectives

This study was conducted to determine the prevalence of smoking, knowledge about the ill effects of smoking on health, and the influence of family members’ smoking habits among Saudi female students.

Methods

This is a type of cross-sectional study. A sample of 1,070 female students was selected by a nonrandom and convenient sampling method from five colleges (Medicine, Business and Administration, Computer Sciences, Education, and Languages and Translation) of King Saud University, Riyadh, Saudi Arabia. A self-administrated questionnaire was used to determine the personal, social, and educational characteristics of the respondents. In addition, questions about their smoking types, status, duration of smoking, knowledge about the ill effects of smoking, daily cigarette consumption, and reasons for quitting smoking were included.

Results

The students’ response rate was 85%. The prevalence of current smoking was 4.3% and 5.6% for cigarettes and water-pipes, respectively, whereas 3.9% of the participants were ex-smokers. The prevalence of current smoking was highest in the College of Business and Administration (10.81%) and lowest in the College of Medicine (0.86%). The majority (77%) of the smokers’ parents (current and ex-smokers) were also smokers. More than half (54%) of the smokers started their smoking habit for entertainment, and 44.4% of the participants did not know that smoking causes serious health problems. The most common factors for quitting smoking were health concerns (54%), religious beliefs (29%), and parent’s advice (17%).

Conclusion

The study concludes that the prevalence of smoking varies in different subject streams and that family and friends have a great influence on individuals starting or stopping smoking. Extensive health education programs are needed to educate young women on the health hazards of smoking and help stop them from smoking.

Lifestyle factors and reproductive health: taking control of your fertility

Approximately 10 to 15% of couples are impacted by infertility. Recently, the pivotal role that lifestyle factors play in the development of infertility has generated a considerable amount of interest. Lifestyle factors are the modifiable habits and ways of life that can greatly influence overall health and well-being, including fertility. Many lifestyle factors such as the age at which to start a family, nutrition, weight, exercise, psychological stress, environmental and occupational exposures, and others can have substantial effects on fertility; lifestyle factors such as cigarette smoking, illicit drug use, and alcohol and caffeine consumption can negatively influence fertility while others such as preventative care may be beneficial. The present literature review encompasses multiple lifestyle factors and places infertility in context for the couple by focusing on both males and females; it aims to identify the roles that lifestyle factors play in determining reproductive status. The growing interest and amount of research in this field have made it evident that lifestyle factors have a significant impact on fertility.

Smoking and dietary inadequacy among Inuvialuit women of child bearing age in the Northwest Territories, Canada

Objective

The prevalence of smoking in Aboriginal Canadians is higher than non-Aboriginal Canadians, a behavior that also tends to alter dietary patterns. Compared with the general Canadian population, maternal smoking rates are almost twice as high. The aim of this study was to compare dietary adequacy of Inuvialuit women of childbearing age comparing smokers versus non-smokers.

Research methods & procedures

A cross-sectional study, where participants completed a culturally specific quantitative food frequency questionnaire. Non-parametric analysis was used to compare mean nutrient intake, dietary inadequacy and differences in nutrient density among smokers and non-smokers. Multiple logistic regression analyses were performed for key nutrients inadequacy and smoking status. Data was collected from three communities in the Beaufort Delta region of the Northwest Territories, Canada from randomly selected Inuvialuit women of childbearing age (19-44 years).

Results

Of 92 participants, 75% reported being smokers. There were no significant differences in age, BMI, marital status, education, number of people in household working and/or number of self employed, and physical activity between smokers and non-smokers. Non-parametric analysis showed no differences in nutrient intake between smokers and non-smokers. Logistic regression however revealed there was a positive association between smoking and inadequacies of vitamin C (OR = 2.91, 95% CI, 1.17-5.25), iron (OR = 3.16, 95% CI, 1.27-5.90), and zinc (OR = 2.78, 95% CI, 1.12-4.94). A high percentage of women (>60%), regardless of smoking status, did not meet the dietary recommendations for fiber, vitamin D, E and potassium.

Conclusions

This study provides evidence of inadequate dietary intake among Inuvialuit of childbearing age regardless of smoking behavior.

Does cigarette smoking affect seminal fluid parameters? A comparative study

OBJECTIVE

To study the effect of cigarette smoking on seminal fluid parameters, namely; volume, sperm concentration, and motility, as well as morphology, leukocyte infiltration, among males complaining of infertility.

METHODS

Between August 2010 and July 2011, seminal fluid analysis was done for 1438 males who are partners of couples who visited the infertility clinic at Prince Rashid Ben Al Hassan Hospital (PRH) for infertility. The men who fit the inclusion criteria (n=960) were classified into two groups: group a (non-smokers; n=564) and group B (smokers; n=396), which represents 41.25% of the study group. Seminal fluid was collected using masturbation after 3-5 days of abstinence then analyzed for volume, sperm count, sperm concentration, motility and morphology. In order to analyze whether the number of cigarettes smoked per day has an effect on the spermatogram; the smoking men were divided into two subgroups: the heavy smokers (n=266) and non-heavy smokers (n=130).

RESULTS

A total of 960 adult males were enrolled. Their age ranged between 21 and 76 years, 564 were non-smokers with mean age of 36. 45±6.27 (Mean±SD). Three-hundred-and-ninety-six were smokers with a mean age of 34.35±4.25 (Mean±SD). There was a significant effect of smoking on the motility of sperms and the ratios of abnormality (p<0.005). Concentration appeared not to be affected by smoking. Furthermore, the group of heavy smokers were found to have lower sperm concentrations and a higher percentage of abnormal sperms compared to the non-heavy smokers.

CONCLUSION

Cigarette smoking has a deleterious effect on some of the seminal fluid parameters (motility, morphology and leukocyte count) which in turn may result in male subfertility.

Persistent environmental pollutants and couple fecundity: the LIFE study

BACKGROUND

Evidence suggesting that persistent environmental pollutants may be reproductive toxicants underscores the need for prospective studies of couples for whom exposures are measured.

OBJECTIVES

We examined the relationship between selected persistent pollutants and couple fecundity as measured by time to pregnancy.

METHODS

A cohort of 501 couples who discontinued contraception to become pregnant was prospectively followed for 12 months of trying to conceive or until a human chorionic gonadotrophin (hCG) test confirmed pregnancy. Couples completed daily journals on lifestyle and provided biospecimens for the quantification of 9 organochlorine pesticides, 1 polybrominated biphenyl, 10 polybrominated diphenyl ethers, 36 polychlorinated biphenyls (PCBs), and 7 perfluorochemicals (PFCs) in serum. Using Cox models for discrete time, we estimated fecundability odds ratios (FORs) and 95% CIs separately for each partner's concentrations adjusting for age, body mass index, serum cotinine, serum lipids (except for PFCs), and study site (Michigan or Texas); sensitivity models were further adjusted for left truncation or time off of contraception (≤ 2 months) before enrollment.

RESULTS

The adjusted reduction in fecundability associated with standard deviation increases in log-transformed serum concentrations ranged between 18% and 21% for PCB congeners 118, 167, 209, and perfluorooctane sulfonamide in females; and between 17% and 29% for p,p´-DDE and PCB congeners 138, 156, 157, 167, 170, 172, and 209 in males. The strongest associations were observed for PCB 167 (FOR 0.79; 95% CI: 0.64, 0.97) in females and PCB 138 (FOR = 0.71; 95% CI: 0.52, 0.98) in males.

CONCLUSIONS

In this couple-based prospective cohort study with preconception enrollment and quantification of exposures in both female and male partners, we observed that a subset of persistent environmental chemicals were associated with reduced fecundity.

Socioeconomic status and number of children among Korean women: the Healthy Twin Study

Objectives

This study aimed to evaluate whether the birth rate is associated with socioeconomic status in the women of the Republic of Korea, where the birth rate is rapidly decreasing.

Methods

This study included 732 females from the Healthy Twin Study, a family-twin cohort. The participants were classified into 3 socioeconomic groups according to their average income, education, and occupation. The association between socioeconomic status and number of children was assessed using gamma regression analysis with a generalized linear mixed model, adjusting for the age group, smoking/alcohol status, and family relationships.

Results

The group with the highest education level had significantly fewer children compared with the group with the lowest education level (p=0.004). However, no significant associations were found according to household income level. The non-manual labor group had significantly fewer children compared with those working as homemakers (p=0.008).

Conclusions

This study aimed to explain the causal relationship between socioeconomic status and number of children. Associations between some socioeconomic status and number of children were found in Korea.

A genome-wide association study of early menopause and the combined impact of identified variants

Early menopause (EM) affects up to 10% of the female population, reducing reproductive lifespan considerably. Currently, it constitutes the leading cause of infertility in the western world, affecting mainly those women who postpone their first pregnancy beyond the age of 30 years. The genetic aetiology of EM is largely unknown in the majority of cases. We have undertaken a meta-analysis of genome-wide association studies (GWASs) in 3493 EM cases and 13 598 controls from 10 independent studies. No novel genetic variants were discovered, but the 17 variants previously associated with normal age at natural menopause as a quantitative trait (QT) were also associated with EM and primary ovarian insufficiency (POI). Thus, EM has a genetic aetiology which overlaps variation in normal age at menopause and is at least partly explained by the additive effects of the same polygenic variants. The combined effect of the common variants captured by the single nucleotide polymorphism arrays was estimated to account for ∼30% of the variance in EM. The association between the combined 17 variants and the risk of EM was greater than the best validated non-genetic risk factor, smoking.

Tobacco and areca nut chewing--reproductive impairments: an overview

A large number of people are using smokeless tobacco and areca nut worldwide. Sufficient data on tobacco smoking have harmful effect on human health and reproduction is available. However, data on the smokeless tobacco and areca nut use on human reproduction is scanty. This overview is an attempt to compose on the consumption of smokeless tobacco and areca nut on human reproduction and some relevant experimental data were also included. The existing studies suggest that tobacco and areca nut chewing alone, together or with other ingredients had reproductive toxic potential. Pregnant women using smokeless tobacco during pregnancy also had adverse effect on pregnancy and its outcome. Thus pregnant women must avoid consumption of any mixture containing areca nut and tobacco in order to protect the pregnancy and outcome. The data suggest that smokeless tobacco use is also harmful as smoking for reproduction and use of areca nut might have further compounded the problem.

University students' perceptions of environmental risks to infertility

BACKGROUND

Canadian young adults may be at risk of future infertility due to the high incidence of sexually transmissible infections (STIs) in this population. Young adults' perceptions of environmental risks, including contaminants, STIs and lifestyle habits on infertility, have not been examined. We have therefore designed a qualitative study to explore risk perceptions, awareness and knowledge of common environmental risk factors for infertility in a multiethnic sample of young adults.

METHODS

Semistructured interviews were carried out with 40 university undergraduate students (16 men and 24 women) in Ottawa, Canada, followed by qualitative analysis of interview transcripts to identify major themes.

RESULTS

The following broad themes described participants' risk perceptions about infertility and (1) environmental contaminants: knowledge gaps, media reports and negative perception of chemicals; (2) STIs: superficial understanding of their role in infertility, general awareness, associations with sexual behaviours and knowledge gaps; and (3) lifestyle: protective benefits of healthy lifestyle, dose or exposure effects for smoking and alcohol, and knowledge gaps. Students demonstrated a superficial understanding of environmental risks, at times relying on media reports and anecdotal information to support their beliefs.

CONCLUSIONS

This next generation of potential infertility patients exhibits a general understanding of environmental risks to infertility; however, young adults are overly optimistic that healthy lifestyle behaviours will safeguard future fertility. STIs represent the most significant modifiable risk factors for this age group; a message that can be supported by sexual and reproductive health education and promotion with greater emphasis on the long-term outcomes of STIs, including infertility.

[First French national survey on lifestyle and toxic factors in infertile couples]

OBJECTIVES

The purpose of our study is to assess, prior to any treatment for infertility, the environment and quality of life of candidate couples for medically assisted procreation (MAP) and the toxic factors which may be related to their difficulty in conceiving.

PATIENTS AND METHODS

A screening questionnaire aimed at 796 patients (348 couples) has been collected by 43 assisted reproductive techniques (ART) centers in France. Stress factors, anxiety, toxic and environmental factors have been recorded and analysed.

RESULTS

Women were on average younger than men (34.9 y ± 5.3 vs. 37.5 y ± 7.5), with a normal BMI, and 78% of them had no children. Sexual relations are regular: 2.14 per week. However, 1 in 8 women reports having sexual problems as opposed to 2 in 100 men (P < 0.0001), the most common problems being painful intercourse, insensitivity and bleeding. Fifty percent of the surveyed women say they have painful periods. Smoking and cannabis use were significantly higher in the men (32% vs. 20% and 6,4% vs. 1,2%). Alcohol consumption is more common in men (32 vs. 23%, P < 0.01). Stress related to infertility was significantly higher in the women (54% vs. 23%; P < 0.001).

DISCUSSION AND CONCLUSION

This first prospective French survey has revealed an increased incidence of smoking and an escalation of sexual problems (decrease in sexual relations, dyspareunia) and dysmenorrhea in women. It has also revealed stress at work in couples, and increased stress levels due to infertility in the female partners participating in this study. Our study suggests that there are numerous toxic and environmental factors which are potentially harmful for a couple's fertility and which should be corrected before any MAP treatment is attempted in order to optimise the results in ART and to increase natural fertility.

Maternal smoking during pregnancy and reproductive health of daughters: a follow-up study spanning two decades

STUDY QUESTION

Does in utero exposure to constituents of cigarette smoke have a programming effect on daughters' age of menarche and markers of long-term reproductive health?

SUMMARY ANSWER

In utero exposure to constituents of cigarette smoke was associated with earlier age of menarche and--to a lesser extent--changes in the testosterone profile of the young women.

WHAT IS KNOWN ALREADY

Studies observe potential effects of in utero exposure to constituents of cigarette smoke on the intrauterine formation of female gonads, but the consequences on long-term reproductive health in daughters remain unclear.

STUDY DESIGN, SIZE AND DURATION

A prospective cohort study was designed using data from 965 pregnant women enrolled prior to a routine 30th-week antenatal examination at a midwifery practice in Denmark from 1988 to 1989 and a follow-up of their 19-21-year-old daughters in 2008.

PARTICIPANTS/MATERIALS, SETTING AND METHODS

The pregnant women provided information on lifestyle factors during pregnancy, including the exact number of cigarettes smoked per day during the first and the second trimesters. A total of 438 eligible daughters were asked to complete a web-based questionnaire on reproductive health and subsequently invited to participate in a clinical examination during 2008. Of the 367 daughters (84%) who answered the questionnaire, 267 (61%) agreed to further examination. Information on menstrual pattern was provided at examination, blood samples were drawn to be analyzed for serum levels of reproductive hormones [FSH, LH, estradiol (E(2)), sex hormone-binding globulin, anti-Müllerian hormone, dehydroepiandrosterone-sulphate (DHEAS), free testosterone and free E(2)] and number of follicles (2-9 mm) were examined by transvaginal ultrasound. The daughters were divided into three exposure groups according to the level of maternal smoking during first trimester [non-exposed (reference), low-exposed (mother smoking >0-9 cigarettes/day) and high-exposed (mother smoking ≥ 10 cigarettes/day)]. Data were analyzed by multiple regression analyses in which we adjusted for potential confounders. Both crude and adjusted test for trend were carried out using maternal smoking during the first trimester as a continuous variable.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed an inverse association between in utero exposure to constituents of cigarette smoke and age of menarche (P = 0.001). Daughters exposed to >0-9 cigarettes/day debuted with -2.7 [95% confidence interval (CI) -5.2 to -0.1] percentage earlier age of menarche, whereas daughters exposed to ≥ 10 cigarettes/day had -4.1 (95% CI: -6.6 to -1.5) percentage earlier age of menarche corresponding to 6.5 (95% CI: -10.7 to -2.2) months. There was a non-significant tendency towards lower levels of testosterone and DHEAS with increasing in utero exposure to constituents of cigarette smoke but no associations with follicle number, cycle length or serum levels of the other reproductive hormones were observed.

LIMITATIONS AND REASONS FOR CAUTION

We collected information on age of menarche retrospectively but the recall time was relatively short (2-10 years) and the reported values were within the normal range of Caucasians. Analyses of reproductive hormones are presented only for the group of daughters who were non-users of hormonal contraceptives because users were excluded, leaving only a low number of daughters available for the analyses (n = 75), as reflected in the wide CIs. The analyses of hormones were further adjusted for menstrual phase at time of clinical examination (follicular, ovulation and luteal phase) because blood samples were not collected on a specific day of the menstrual cycle.

WIDER IMPLICATIONS OF THE FINDINGS

This study supports the limited evidence of an inverse association between maternal smoking during pregnancy and age of menarche and further addresses to what extent reproductive capacity and hormones may be programmed by maternal smoking during pregnancy. A trend toward earlier maturation of females is suggested to have implications on long-term reproductive function.

STUDY FUNDING/COMPETING INTEREST(S)

Supported by a scholarship from The Lundbeck Foundation (R93-A8476). No conflict of interest declared.

Occurrence of ²¹⁰Po and biological effects of low-level exposure: the need for research

BACKGROUND

Polonium-210 (²¹⁰Po) concentrations that exceed 1 Bq/L in drinking-water supplies have been reported from four widely separated U.S. states where exposure to it went unnoticed for decades. The radionuclide grandparents of ²¹⁰Po are common in sediments, and segments of the public may be chronically exposed to low levels of ²¹⁰Po in drinking water or in food products from animals raised in contaminated areas.

OBJECTIVES

We summarized information on the environmental behavior, biokinetics, and toxicology of ²¹⁰Po and identified the need for future research.

METHODS

Potential linkages between environmental exposure to ²¹⁰Po and human health effects were identified in a literature review.

DISCUSSION

²¹⁰Po accumulates in the ovaries where it kills primary oocytes at low doses. Because of its radiosensitivity and tendency to concentrate ²¹⁰Po, the ovary may be the critical organ in determining the lowest injurious dose for ²¹⁰Po. ²¹⁰Po also accumulates in the yolk sac of the embryo and in the fetal and placental tissues. Low-level exposure to ²¹⁰Po may have subtle, long-term biological effects because of its tropism towards reproductive and embryonic and fetal tissues where exposure to a single alpha particle may kill or damage critical cells. ²¹⁰Po is present in cigarettes and maternal smoking has several effects that appear consistent with the toxicology of ²¹⁰Po.

CONCLUSIONS

Much of the important biological and toxicological research on ²¹⁰Po is more than four decades old. New research is needed to evaluate environmental exposure to ²¹⁰Po and the biological effects of low-dose exposure to it so that public health officials can develop appropriate mitigation measures where necessary.