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

Low grade inflammation, as evidenced by basal high sensitivity CRP, is not correlated to outcome measures in IVF

PURPOSE

To assess the relationship between low-grade inflammation, measured as basal high sensitivity (hs)-CRP, and IVF outcome.

METHODS

We recruited a total of 220 women undergoing infertility work up prior to IVF. Patients were selected for a BMI < 30 kg/m(2) with an upper age limit of 40 years. Serum hs-CRP levels were measured on day 3 of a spontaneous menstrual cycle preceding ovarian stimulation. A sensitive two-site ELISA was used for analysis. Dose of gonadotrophins required, follicles days 8 and 10, number of oocytes collected, number of oocytes fertilised and pregnancy outcome were recorded.

RESULTS

Median hs-CRP was 1.08 mg/L (0.43-3.00 mg/L). The hs-CRP was significantly related to BMI (r = 0.386, P < .001) but not to age and smoking habit. There were no significant relationships between basal hs-CRP and any of the measured IVF outcomes.

CONCLUSIONS

These findings demonstrate that serum hs-CRP concentration is not a predictive marker of cycle or pregnancy outcome in women undergoing IVF treatment.

Predicting fertility

Various predictors of fertility have been described, suggesting that none are ideal. The literature on tests of ovarian reserve is largely limited to women undergoing in vitro fertilization, and is reliant on the use of surrogate markers, such as cycle cancellation and number of oocytes retrieved, as reference standards. Currently available prediction models are far from ideal; most are applicable only to subfertile women seeking assisted reproduction, and lack external validation. Systematic reviews and meta-analyses of predictors of fertility are limited by their heterogeneity in terms of the population sampled, predictors tested and reference standards used. There is an urgent need for consensus in the design of these studies, definition of abnormal tests, and, above all, a need to use robust outcomes such as live birth as the reference standard. There are no reliable predictors of fertility that can guide women as to how long childbearing can be deferred.

Cigarette smoking and reproductive function

PURPOSE OF REVIEW

To perform a systematic review of the literature on the relationship between cigarette smoking and reproductive function. Whenever possible, this review is focused on the most recently published studies (mainly the past 2 years). Nevertheless, in many instances older literature was too relevant not to be taken into account.

RECENT FINDINGS

Tobacco compounds exert a deleterious effect on the process of ovarian follicle maturation. This effect is expressed by worse in-vitro fertilization parameters in cycles performed on women with smoking habits. Also, uterine receptiveness is significantly altered by the smoking habit. In men, cigarette smoking reduces sperm production, increases oxidative stress, and DNA damage. Spermatozoa from smokers have reduced fertilizing capacity, and embryos display lower implantation rates. Even in-utero exposition to tobacco constituents leads to reduced sperm count in adult life.

SUMMARY

A strong body of evidence indicates that the negative effect of cigarette smoking on fertility comprises fairly every system involved in the reproductive process. Couples in reproductive age should be strongly discouraged to smoke.

In vitro assessment of reproductive toxicity of tobacco smoke and its constituents

Epidemiological studies have repeatedly shown that reproductive processes in pregnant women are adversely affected by exposure to cigarette smoke. The potential reproductive targets of smoke during pregnancy include the ovaries, oviducts, uterus, placenta, umbilical cord, and embryo/fetus. In vitro methods for studying the effects of smoke and its individual components have been developed and applied to each of these reproductive targets. In vitro assays have been useful in determining the biological processes that are affected in the reproductive organs and in identifying the cellular and molecular targets of smoke in each organ. In vitro methods have also been used to study the mechanism of action of smoke constituents, such as nicotine, on specific processes in reproductive organs and to screen smoke solutions to identify the molecules that affect reproduction. In general, data collected in vitro have confirmed, extended, and helped explain what has been learned from epidemiological studies. This review summarizes some of the in vitro assays that have been used to study cigarette smoke's effect on the nonpregnant and pregnant female reproductive tract and spotlights examples of their applications.

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.

Effect of nicotine on in vitro maturation of bovine oocytes

The putative effect of nicotine on maturation and the chromosomal complement of bovine oocytes were investigated in the present study. Cumulus-enclosed oocytes were incubated in maturation medium with 0, 0.5, 1.0, 2.5, 5.0, and 10.0 mmol concentrations of nicotine. The results indicated that: (1) nicotine affected cumulus cell expansion in a dose-dependent manner and the perivitelline space failed to form when concentrations were equal to or greater than 5.0 mmol; (2) oocytes treated with 0.5 and 1.0 mmol nicotine concentrations resulted in maturation rates (83.3% and 85.9%, respectively) which was similar to the control (86.2%), whereas treatment with 2.5 and 5.0 mmol concentrations significantly decreased maturation rates to 70.2% and 26.7%, respectively; (3) nicotine at or over 2.5 mmol caused extremely irregular meiotic spindles and interrupted microfilament organization; (4) chromosomal analyses of oocytes with PB1 showed that oocytes derived from 0.5 and 1.0 mmol nicotine groups had haploid complements similar to the control (87-90%), but when the concentrations were increased to 2.5 and 5.0 mmol the haploid state was significantly reduced to around 70%; (5) oocytes at GVBD (germinal vesicle breakdown) and metaphase I stages were less affected by nicotine at 5.0 and 10.0 mmol concentrations than GV-stage oocytes; (6) maturation rates of the short-term nicotine-treated oocytes could be improved when subsequently incubated in normal maturation medium. Prolonged culture of nicotine-pretreated oocytes resulted in self-activation and some oocytes formed 1 or 2 pronuclei. In conclusion, nicotine affects bovine oocyte cumulus cell expansion, maturation rate, and chromosomal complement in a dose-dependent and an oocyte-stage-dependent manner.

Nicotine alters bovine oocyte meiosis and affects subsequent embryonic development

The effects of nicotine on nuclear maturation and meiotic spindle dynamics of bovine oocytes and subsequent embryonic development were investigated. Maturation rates (85%-94%) derived from nicotine treatments at 0.01 to 1.0 mM were similar to the control (86%), but significantly decreased at 2.0 to 6.0 mM. Haploid complements of metaphase II oocytes in 0.01 to 1.0 mM nicotine (approximately 90%) were similar to the control, while lower (ranged from 63% to 76%, P < 0.05 or P < 0.01) haploid oocytes were observed in the 2.0 to 6.0 mM nicotine groups. The majority of the PB1-free oocytes derived from 3.0 to 6.0 mM nicotine treatments were diploidy (2n = 60). Spindle microtubules changed from characteristically being asymmetrical in the controls to being equally distributed into two separate chromosome groups in the nicotine treatments. Nicotine disorganized the microfilament organization and inhibited the movement of anaphase or telophase chromosomes to the cortical area. The inhibited two chromosome groups became two spindles that either moved close in proximity or merged entirely together resulting in diploidy within the affected oocyte. Nicotine treatment significantly reduced the rate of cleavage and blastocyst development after parthenogenetic activation. Diploidy and cell number were drastically reduced in the resultant blastocysts. In conclusion, nicotine can alter the normal process of bovine oocyte meiosis and affects subsequent embryonic development.

Facteurs cliniques et résultats du don d'ovocytes

This article aims at reviewing the literature in order to provide a summary of the actual knowledge about the clinical factors of the oocyte recipient (other than those affecting the morphology of the uterine cavity) influencing the outcome of oocyte donation cycles. Recipient age, from 45 years onwards, is clearly associated with a poorer outcome in oocyte donation cycles as well as the presence of a hydrosalpinx. The negative impact of smoking has recently been confirmed. The exact influence of a high body mass index is under examination but it is likely that it is associated with a lower ongoing pregnancy rate. Endometriosis does not have a negative impact when standard endometrial priming protocols are used in oocyte donation. During endometrial priming, serum estradiol levels and endometrial thickness, if >5 mm, does not influence negatively the outcome; however duration of estrogen treatment of more than 7 weeks is associated with a diminished pregnancy and implantation rate.

The impact of lifestyle risk factors on female infertility

BACKGROUND

Over 2 million couples in the United States are infertile. The literature reflects a number of potential lifestyle risks that have been associated with the development of this condition; however, few studies have investigated these risks concurrently. With knowledge of the importance of behavioral threats to fertility, women's health care providers will be in a better position to screen and assist women to modify their fertility risks.

OBJECTIVES

The objectives of this study were (1) to identify lifestyle factors associated with infertility in women by comparing a sample of infertile women with a group of fertile women and (2) to offer recommendations to women's health providers, on counseling women at risk for infertility.

METHODS

A re-examination of the 1995 National Survey of Family Growth (NSFG) allowed for the investigation of lifestyle factors associated with infertility in women. Using a conceptual model of health behavior to guide the selection of variables, together with multiple logistic regression techniques, an explanatory model of infertility was estimated on a sample of 824 women between the ages of 16 and 45 years.

RESULTS

Factors directly related to infertility included increasing age, a history of an ectopic pregnancy, current smoking, obesity, and self reported health status. Protective effects were associated with a history of condom use and having had a Pap smear in the last year.

CONCLUSIONS AND IMPLICATIONS

Routine well-women visits offer an excellent opportunity to begin to address the impact of selected risk factors for infertility. Clinicians can utilize these visits to target appropriate interventions for initiating, repeating, and reinforcing messages on fertility risk.

Thyroid disease and female reproduction

The menstrual pattern is influenced by thyroid hormones directly through impact on the ovaries and indirectly through impact on SHBG, PRL and GnRH secretion and coagulation factors. Treating thyroid dysfunction can reverse menstrual abnormalities and thus improve fertility. In infertile women, the prevalence of autoimmune thyroid disease (AITD) is significantly higher compared to parous age-matched women. This is especially the case in women with endometriosis and polycystic ovarian syndrome (PCOS). AITD does not interfere with normal foetal implantation and comparable pregnancy rates have been observed after assisted reproductive technology (ART) in women with and without AITD. During the first trimester, however, pregnant women with AITD carry a significantly increased risk for miscarriage compared to women without AITD, even when euthyroidism was present before pregnancy. It has also been demonstrated that controlled ovarian hyperstimulation (COH) in preparation for ART has a significant impact on thyroid function, particularly in women with AITD. It is therefore advisable to measure thyroid function and detect AITD in infertile women before ART, and to follow-up these parameters after COH and during pregnancy when AITD was initially present. Women with thyroid dysfunction at early gestation stages should be treated with l-thyroxine to avoid pregnancy complications. Whether thyroid hormones should be given prior to or during pregnancy in euthyroid women with AITD remains controversial. To date, there is a lack of well-designed randomized clinical trials to elucidate this controversy.

Follicle growth is inhibited by benzo-[a]-pyrene, at concentrations representative of human exposure, in an isolated rat follicle culture assay

BACKGROUND

The adverse effects of cigarette smoking on human fertility have been well documented. However, the mechanism(s) underlying the detrimental effects of cigarette smoking are unknown. Using a novel isolated rat follicle culture assay, we tested the hypothesis that benzo-[a]-pyrene (B[a]P), a constituent of cigarette smoke, can inhibit follicle growth.

METHODS

B[a]P levels were quantified in the serum and follicular fluid (FF) of women undergoing in vitro fertilization (IVF) treatment exposed to mainstream smoke (n = 19) and non-smokers (n = 10) by gas chromatography mass spectrometry. Isolated rat follicles were cultured with increasing concentrations of B[a]P (1.5-300 ng ml(-1)) and follicle diameter was measured daily.

RESULTS

Mean ( +/- Standard error of the mean) B[a]P) was quantified in the serum (0.40 +/- 0.13 ng ml(-1)) and FF (1.32 +/- 0.68 ng ml(-1)) of women who smoke. IVF stimulation and outcome measures were similar between female smokers and non-smokers with the exception of implantation rate and pregnancy rate, which were both significantly lower (P < 0.05) in the MS group. B[a]P treatment significantly reduced rat follicle diameter and attenuated FSH stimulated growth in a dose-dependent manner, beginning at 1.5 ng ml(-1).

CONCLUSIONS

Our data suggest that B[a]P, at levels representative of those measured in human FF, may adversely affect follicle development and be an ovarian toxicant.

The impact of lifestyle factors on reproductive performance in the general population and those undergoing infertility treatment: a review

This evidence-based review focuses on the impact of potentially modifiable, non-communicable lifestyle factors on reproductive performance in the general population and the infertile population undergoing assisted reproductive technology (ART) treatment. The impact of several lifestyle factors including; age, weight, smoking, diet, exercise, psychological stress, caffeine consumption, alcohol consumption and exposure to environmental pollutants are included in the review. The databases of Medline, PubMed and Cinahl were searched to identify relevant publications. There is strong evidence that age, weight and smoking impact on general health and adversely on reproductive performance. However there is a need for further research focusing specifically on the relationship between diet and various levels of exercise on reproductive performance. There are several other factors such as psychological stress, caffeine consumption, alcohol consumption and exposure to environmental pollutants that have been implicated but the evidence is equivocal. It is concluded that lifestyle modification can assist couples to conceive spontaneously or optimize their chances of conception with ART treatment.

Early exposure to smoking and future fecundity among Danish twins

Several studies have examined the effect of in utero exposure to smoking and fecundity among the offspring but the findings are contradictory. We therefore studied the waiting time to first pregnancy (TTP) and exposure to smoking in utero and childhood among Danish twins born between 1931 and 1952. Information about TTP, exposure to mothers smoking in pregnancy, exposure to smoking in childhood and current smoking among the male twins and smoking in their own pregnancy among female twins was collected by interview. Fecundability odds ratio (FOR) estimating the odds of conception in a cycle among exposed compared to the unexposed were calculated separately for female and male twins. A total of 1653 female and 1598 male twins reported a TTP. Female twins, exposed in utero, had reduced fecundability after control for confounders (FOR = 0.81; 95% CI 0.67-0.99). A nonsignificant increase in fecundity among male twins exposed to smoking in utero was found (FOR = 1.12; 95% CI 0.89-1.40). Among dizygotic twins of opposite sex sharing the same in utero exposures, the future fecundity of the male twin was unaffected by in utero exposure (FOR = 0.97; 95% CI 0.60-1.55) whereas the female twin had reduced fecundity (FOR = 0.65; 95% CI 0.47-0.91). This study supports that smoking is hazardous to the female fetus not only in the short term but also affects her future ability to conceive and makes it even more important to advise pregnant women to stop smoking.

Smoking and infertility

Approximately 30% of reproductive age women and 35% of reproductive age men in the United States smoke cigarettes. Substantial harmful effects of cigarette smoke on fecundity and reproduction have become apparent but are not generally appreciated.

Fécondation in vitro et tabac: intérêt de la cotininurie et de l'analyseur de monoxyde de carbone expiré

OBJECTIVE

To study the correlation between expired air carbon (EACO) and urinary cotinine, and to determine the impact of tobacco smoking on in vitro fertilization (IVF) results.

PATIENTS AND METHODS

We studied prospectively 221 patients in our ART center from October 2002 to October 2004: 51 active smokers, 85 passive smokers, and 85 non-smokers. Patients were classified into active, passive smokers, or non-smokers, based on a questionnaire. We measured urinary cotinine and EACO on the embryo transfer day and we recorded the IVF parameters.

RESULTS

Two hundred and twenty-one patients were included. We observed a 17.2% reduction of estradiolemy (P=0.05), a 1.5% reduction of pregnancies (NS), a 7.8% reduction of infants born alive (NS), a 28.5% reduction of twin pregnancies (P=0.06), as well as a 10% increase of miscarriages (NS) in the active smokers in comparison with non-smokers (the same trends were observed between active and passive smokers). EACO and urinary cotinine were well correlated. There was a negative correlation between estradiolemy and urinary cotinine (R=-0.15, P=0.02).

DISCUSSION AND CONCLUSION

Tobacco smoking intensity may be dilatory on IVF results. There is a high correlation between EACO and urinary cotinine. Other larger studies would probably obtain results more statistically significant.

Maternal exposure to second-hand tobacco smoke and pregnancy outcome among couples undergoing assisted reproduction

BACKGROUND

Exposure to second-hand tobacco smoke is preventable, yet common. This study assessed relationships between maternal exposure to second-hand tobacco smoke and adverse pregnancy outcomes.

METHODS

We measured cotinine (a biomarker of tobacco smoke) in urine from 921 women undergoing assisted reproductive technologies (ARTs) between 1994 and 1998. We also collected information on self-reported exposure to second-hand smoke at home or at work, in addition to parental smoking during the women's childhood.

RESULTS

In crude analysis, creatinine-adjusted cotinine levels were associated with a slight decrease in implantation rate among non-smoking women (11.1% in the lowest cotinine quintile versus 8.2% in the highest cotinine quintile; P=0.13). However, in multivariate logistic regression, cotinine levels above the median were not associated with failed fertilization, failed implantation or spontaneous abortion, nor was there evidence of a dose-response relationship among cotinine quintiles. After excluding women in couples diagnosed with male factor infertility, there were increased odds of having a spontaneous abortion among non-smoking women who reported that both parents smoked while they were children growing up compared with women reporting that neither parent smoked [adjusted odds ratio (OR) = 4.35; 95% confidence interval (CI) = 1.04-18.1].

CONCLUSIONS

Female exposure to second-hand smoke as a child or in utero may be associated with an increased risk of spontaneous abortion in adulthood. However, this may be a chance finding due to multiple comparisons. Similar associations should be explored in additional studies with more refined estimates of childhood and in utero exposure to tobacco smoke.

Tabac et fertilité chez la femme et l'homme

Cigarette smoking consequences on female and male reproduction have been evaluated for twenty years only and thus poorly spread in the general population. However, several studies have noticed noxious effects of tobacco before and after conception, in both women and men, from smokers gametes to their offspring. This negative impact occurs in spontaneous as well as in assisted reproduction (ART). For women, pregnancy rate is decreased, early spontaneous abortions are increased and ovarian reserve is altered. For men, standard sperm parameters are modified and spermatozoon nuclear quality is compromised. One of the mechanisms involved in those anomalies could be the oxidative stress produced by some cigarette smoking components. The consequences on smokers offspring are hardly evaluated yet: pathologies of the respiratory system, decrease of fecundity and cancers outcomes. In conclusion, it seems obvious that smokers - men as women - have to quit smoking before having a parental project.

Fetal and neonatal exposure to nicotine disrupts ovarian function and fertility in adult female rats

Women born to mothers who smoked during pregnancy have been shown to have impaired fertility, although the mechanisms underlying this association are unknown. Nicotine administration in adult animals has adverse effects on the ovary and uterus; however, the effects of fetal exposure to nicotine on postnatal ovarian function have not been determined. The goal of this study was to assess the effect of fetal and neonatal exposure to nicotine on ovarian function and fertility of the offspring. Nulliparous female Wistar rats were given 1 mg.kg-1.d-1 nicotine bitartrate, subcutaneously for 14 d prior to mating, during pregnancy and throughout lactation until weaning. Measures of fertility, breeding success, and serum levels of ovarian steroid hormones in offspring were assessed at 4 and 6 mo of age. Fetal and neonatal exposure to nicotine significantly increased the time to pregnancy as the animals aged. Similarly, evidence of altered ovarian steroidogenesis including increased serum progesterone concentrations and a decreased estrogen:progesterone ratio was observed in 6-mo-old animals. We conclude that fetal and neonatal exposure to nicotine results in delayed ovarian dysfunction in adult female offspring.

Lifestyle choices, diet, and insulin sensitizers in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is significantly affected by environmental regulators impacting on genetic predisposition. Lifestyle changes can significantly modulate the phenotype of this disease. Diet, exercise, smoking, stress, and other factors adversely affect reproductive outcomes in PCOS. These influences can be modulated by structure change in an individual or group. Lifestyle choices should be discussed in this group of patients. The role of insulin sensitizers, including metformin, has still to be determined in this condition.

The effect of female tobacco smoking on IVF outcomes

BACKGROUND

Cigarette smoking is widely believed to be associated with decreased fecundity in naturally conceiving populations; however, the effect of female smoking on pregnancy outcomes in patients undergoing IVF is unclear.

METHODS

A retrospective analysis of 389 consecutive patients undergoing first cycle IVF was performed. Outcomes of peak estradiol (E(2)) levels, log mean ovarian volume, number of oocytes retrieved, oocyte maturity in ICSI, fertilization rate, cleavage rate, embryo quality, percentage of high-quality embryos, pregnancy and live birth were assessed in patients reported as never smokers, past smokers and current smokers. Potential confounding variables evaluated included day 3 FSH, number of oocytes retrieved, embryo quality, caffeine and alcohol consumption. The population was also stratified by female age (<35 and >or=35 years).

RESULTS

A total of 9.3% of our patients reported current smoking and 12.1% reported a history of smoking. Smoking status did not significantly affect pregnancy outcome, live birth rate or any other indicated outcome.

CONCLUSIONS

A total of 21.4% of IVF patients in this study had past or present exposure to cigarette smoking with no measurable effect on IVF outcome.

Nicotine downregulates the l-selectin system that mediates cytotrophoblast emigration from cell columns and attachment to the uterine wall

Here we show that maternal smoking downregulated, in a dose-dependent manner, cytotrophoblast expression of l-selectin and its TRA-1-81-reactive carbohydrate ligands. Cell islands -- cell columns that fail to make uterine attachments, often more numerous in the placentas of smokers -- exhibited an even greater downregulation of the l-selectin adhesion system. These effects were attributable to nicotine, since exposure of explanted villi to this drug in vitro reproduced the effects observed in situ. Videomicroscopy showed that the downstream consequences included inhibition of all stages of cytotrophoblast outgrowth from columns, including rolling adhesion within columns and generation of invasive cells at the distal ends. These results suggest that nicotine, acting through the l-selectin adhesion system, impairs the development of cell columns that connect the fetal portion of the placenta to the uterus, one possible reason why women who smoke have a much harder time achieving and sustaining pregnancy than their nonsmoking counterparts.

Smoking impairs angiogenesis during maturation of human oocytes

OBJECTIVE

This study determines whether smoking influences ovarian vascularization which thus may impair follicular development.

DESIGN

Prospective laboratory study of follicular fluids and granulosa cells from patients undergoing in vitro fertilization.

SETTING

University Hospital Aachen, Germany.

PATIENT(S)

Fifty smoking women and 50 nonsmoking women.

INTERVENTION(S)

Cultivation of human granulosa cells. Cultivation of human umbilical vein endothelial cells (HUVECs) with either granulosa cell-conditioned medium or follicular fluid. Determination of clinical parameters.

MAIN OUTCOME MEASURE(S)

Quantification of soluble vascular endothelial growth factor receptor 1 (sVEGFR-1) and cotinine.

RESULT(S)

Mean sVEGFR-1 concentration in follicular fluid of smokers was 499.6 pg/mL compared with 159.2 pg/mL in nonsmokers. Correspondingly, supernatant of HUVECs cultured with follicular fluid from smoking and nonsmoking women showed, respectively, 1,174.1 pg/mL versus 794.2 pg/mL sVEGFR-1. The HUVECs incubated with conditioned medium from smokers' granulosa cells at culturing days 5, 9, 13, and 17 secreted, respectively, 1,712.4, 1,560.6, 1,619.0, and 1,635.0 pg/mL sVEGFR-1, whereas nonsmokers showed, respectively, 1,147.6, 1,067.2, 1,135.9, and 1,206.3 pg/mL sVEGFR-1. Mean cotinine concentration in smoking women was 83.9 ng/mL and in nonsmoking was 2.8 ng/mL. In all four comparisons, differences between groups reached statistical significance.

CONCLUSION(S)

This study showed that smokers secrete significantly higher amounts of sVEGFR-1 than nonsmokers, which may result in decreased ovarian vascularization and reduced oocyte maturation.

Modifiable risk factors for impaired fertility in women: What nurse practitioners need to know

PURPOSE

To provide an overview of impaired fertility in childbearing-aged women, to review the current research on modifiable lifestyle risk factors implicated in its development, and to suggest strategies for nurse practitioners (NPs) to assist women in behavioral changes that will allow them to protect their fertility.

DATA SOURCES

Original research articles and comprehensive review articles identified through Medline, CINAHL, and OVID databases.

CONCLUSIONS

Research has shown that advancing age, a history of a sexually transmitted infection and/or pelvic inflammatory disease, extremes of body weight, and tobacco and caffeine use are potentially modifiable risk factors in the development of impaired fertility.

IMPLICATIONS FOR PRACTICE

NPs must be aware of the link between these behaviors and the development of impaired fertility in order to assist women in preserving their fertility. Individual counseling, education, and community-wide education strategies are discussed.

Ovarian response to stimulation of HIV-positive patients during IVF treatment: a matched, controlled study

BACKGROUND

Our aim was to compare the ovarian response of HIV-positive and -negative patients during IVF.

METHODS

Setting - HIV and IVF reference university hospital. Twenty-seven HIV-infected patients who had undergone IVF between March 2000 and March 2005 were matched with 77 HIV-negative patients for age, aetiology of infertility, whether it was primary or secondary infertility, duration of infertility, history of pelvic surgery and type of pituitary inhibition. Outcome - poor responders were defined using one of the following criteria: a cancelled cycle (for insufficient ovarian response), less than four mature follicles (> or = 16 mm), peak serum levels of E2 lower than 1000 pg/ml.

RESULTS

There were no differences between the two groups of patients for the matched criteria. The proportion of African women and of women with a history of pelvic inflammatory disease was significantly higher among HIV patients than among the control group. With the exception of a lower number of transferred embryos among HIV-positive patients versus HIV-negative ones (1.3 versus 1.9; P = 0.035), there was no significant difference between the two groups of patients regarding ovarian response parameters.

CONCLUSION

HIV-infected patients who are in good general condition and who are matched to a control group present a similar ovarian response to stimulation, suggesting the existence of a similar ovarian reserve.

Smoking and reproduction: the oviduct as a target of cigarette smoke

The oviduct is an exquisitely designed organ that functions in picking-up ovulated oocytes, transporting gametes in opposite directions to the site of fertilization, providing a suitable environment for fertilization and early development, and transporting preimplantation embryos to the uterus. A variety of biological processes can be studied in oviducts making them an excellent model for toxicological studies. This review considers the role of the oviduct in oocyte pick-up and embryo transport and the evidence that chemicals in both mainstream and sidestream cigarette smoke impair these oviductal functions. Epidemiological data have repeatedly shown that women who smoke are at increased risk for a variety of reproductive problems, including ectopic pregnancy, delay to conception, and infertility. In vivo and in vitro studies indicate the oviduct is targeted by smoke components in a manner that could explain some of the epidemiological data. Comparisons between the toxicity of smoke from different types of cigarettes, including harm reduction cigarettes, are discussed, and the chemicals in smoke that impair oviductal functioning are reviewed.

Cigarette smoking and the risk of goitre and thyroid nodules amongst parous women

OBJECTIVES

To clarify the mechanisms by which smoking is associated to toxic and nontoxic goitre and thyroid nodules.

DESIGN

Cohort study.

SETTING

Sweden.

SUBJECTS

A cohort of 874,507 parous women identified through the Medical Birth Registry, with smoking behaviour assessed through self-reported information at the first pre-natal visit, and follow-up between 1983 and 1997.

MAIN OUTCOME MEASURES

Hospital diagnoses of toxic and nontoxic goitre and thyroid nodules, identified by record-linkage with the national Inpatient Registry. Cox regression was employed to estimate the hazard ratio (HR) of smokers compared with nonsmokers and the corresponding 95% confidence limits (CL).

RESULTS

There was a significantly increased risk of goitre and nodules amongst smokers. The positive association was stronger for toxic (age adjusted HR = 1.94, CL = 1.74-2.16) than for nontoxic goitre and nodules (age-adjusted HR = 1.26; CL = 1.14-1.38). There was generally no clear risk trend with regard to amount smoked (below and above 10 cigarettes per day). Elevated body mass attenuated these associations, whilst being born in Swedish areas of endemic goitre enhanced the association with nontoxic goitre and nodules.

CONCLUSIONS

Smoking enhances the risk of thyroid goitre and nodules requiring hospital admission. Iodine deficiency and body weight are likely to be important modifiers of the risk of thyroid hyperplastic diseases amongst smokers.

Sidestream smoking is equally as damaging as mainstream smoking on IVF outcomes

BACKGROUND

Cigarette smoking (CS) is a widely recognized health hazard, yet it remains prevalent in society and the effects of environmental tobacco smoke exposure on fertility are unknown. Our objective was to measure the effects of CS on the fertility of mainstream (MS) or sidestream (SS) smoke-exposed women compared to their non-smoking (NS) counterparts.

METHODS

This retrospective study investigated 225 female patients undergoing IVF (n = 97) or ICSI (n = 128). Patients were grouped based on their smoking status for comparison. This included: 39 MS (18 IVF and 21 ICSI); 40 SS (16 IVF and 24 ICSI); and 146 NS (63 IVF and 83 ICSI) women. Fertility treatment outcomes including embryo quality, implantation and pregnancy rate were measured.

RESULTS

No difference in embryo quality between the three groups was observed. However, there was a significant difference in implantation rate (MS = 12.0%, SS = 12.6%, and NS = 25.0%) and pregnancy rate (MS = 19.4%, SS = 20.0%, and NS = 48.3%) per embryo transfer.

CONCLUSIONS

Despite similar embryo quality there was a striking difference in implantation and pregnancy rates of MS and SS smokers when compared with NS. Our data demonstrate that the effects of SS smoking are equally as damaging as MS smoke on fertility.

Effects of subfertility cause, smoking and body weight on the success rate of IVF

BACKGROUND

We investigated the separate and combined effects of smoking and body mass index (BMI) on the success rate of IVF for couples with different causes of subfertility.

METHODS

The success rate of IVF was examined in 8457 women. Detailed information on reproduction and lifestyle factors was combined with medical record data on IVF treatment. All IVF clinics in The Netherlands participated in this study. The main outcome measures were live birth rate per first cycle of IVF differentiated for the major predictive factors.

RESULTS

For male subfertility the delivery rate per cycle was significantly lower than unexplained subfertility, OR of 0.70 (95% CI 0.57-0.86); for tubal pathology, the delivery rate was slightly lower, OR = 0.86 (95% CI 0.70-1.01). Smoking was associated with a significantly lower delivery rate was slightly lower; for OR = 0.72 (95% CI 0.61-0.84) and a significantly higher abortion rate compared to non-smoking delivery rates of 21.4% and 16.4%, respectively (P=0.02). Women with a BMI of > or = 27 kg/m2 had a significantly lower delivery rate, with an OR of 0.67 (95% CI 0.48-0.94), compared with normal weight women (BMI > or = 20 and <27 kg/m2).

CONCLUSIONS

Both smoking and overweight unfavourably affect the live birth rate after IVF. The devastating impact of smoking on the live birth rate in IVF treatment is comparable with an increase in female age of >10 years from age 20 to 30 years. Subfertile couples may improve the outcome of IVF treatment by lifestyle changes.

The adverse effects of maternal smoking on the human placenta: A review

Studies of placental pathologies associated with maternal cigarette smoking have led to many interesting observations. For example, maternal smoking impairs human placental development by changing the balance between cytotrophoblast (CTB) proliferation and differentiation. It is likely that chronic exposure to tobacco constituents in early pregnancy can affect placental development directly or indirectly by reducing blood flow, which creates a pathologically hypoxic environment. To understand this process at a molecular level, tissue samples from non-smoking and smoking mothers were studied to determine whether active and/or passive cigarette smoke exposure affects CTB expression of molecules that govern cellular responses to oxygen tension: the von Hippel-Lindau tumor suppressor protein (pVHL), hypoxia-inducible transcription factors (HIFs) and vascular endothelial growth factor-A (VEGF). The results show that maternal smoking dysregulates CTB expression of all three types of molecules. In addition, cell columns and proliferating cells were reduced while there was a corresponding increase in cell islands. All three phenomena were most obvious in the placentas of heavy smokers. Interestingly, a subset of the aforementioned effects can be detected in samples obtained from women who were passively exposed to cigarette smoke during pregnancy. These observations suggest that tobacco constituents exert direct effects on CTB proliferation and differentiation and help to explain the mechanisms by which smoking negatively effects human pregnancy outcome.

Time trends in waiting time to pregnancy among Danish twins

BACKGROUND

Little is known about time trends in fecundity because few population-based data are available. In a survey among female twins born from 1953 to 1976, their time to pregnancy did not differ from singletons and can be considered to represent the fecundity of the general population.

METHODS

Information was collected by interview about waiting time to first pregnancy (TTP) and any periods of subfecundity among both male and female twins born between 1931 and 1952. Trends were analysed by considering the year of birth of the index person (birth cohort effect) or year at which the first attempt started (period effect).

RESULTS

Eighty-five percent of male and 81.3% of female eligible twins participated. A total of 1598 male twins and 1653 female twins reported a TTP value and 1671 men and 1715 women had a value for their first attempt to conceive including unsuccessful attempts. No overall trends in either male or female TTP were observed with increasing year of birth or of starting time, after adjustment for confounders, but for attempts fecundity increased among female twins by year of birth or of starting the attempt. A decreasing risk of severe infertility with increasing year of birth or year for start of the attempt was observed among male twins, but this observation was based on only 81 men and was not seen among female twins.

CONCLUSION

No decreasing trend in fecundity was observed among Danish twins born between 1931 and 1952 who had completed their reproduction. Female twins had a slight increase in fecundity, and men a decrease in severe infertility. In addition, TTP was apparently well reported and recalled for up to 50 years among both male and female twins.

Female and male lifestyle habits and IVF: what is known and unknown

There is no greater tribute to the importance and efficacy of IVF than the fact that >1 x 10(6) babies have been born to infertile couples since its clinical introduction in 1978. Despite enormous advances regarding the technical aspects of the IVF procedure, the parents' contribution has virtually been ignored when considering aspects that influence success rates. This systematic review focuses on the effects of female and male lifestyle habits (specifically: smoking, alcohol and caffeine use, and psychological stress) on the reproductive endpoints of IVF (i.e. oocyte aspiration, fertilization, embryo transfer, achievement of a pregnancy, live birth delivery, and perinatal outcomes, e.g. low birthweight, multiple gestations). What is currently known in the field of lifestyle habits and IVF? There is compelling evidence that smoking has a negative influence on IVF outcomes, whereas for stress, the evidence is suggestive but insufficient due to the heterogeneity of studies. The evidence for the effects of alcohol and caffeine on IVF is inadequate, and therefore unknown, due to the scarcity of studies.

Environmental and occupational factors affecting fertility and IVF success

Reproductive function has been shown to be sensitive to changes in the physical, psychosocial and chemical environments. Although reproductive effects of occupational exposure to hazardous chemicals have been well documented in the literature, the potential effects of chemical contaminants at levels representative of contemporary exposures in the general population are much less certain. Evidence for adverse effects of exposure to environmental contaminants is more conclusive among the lower animals than for humans where considerable controversy remains. In addition to potential reproductive hazards of exposure to environmental contaminants, there is also evidence for adverse reproductive effects of the physical and psychosocial environments. In this review we focus on the difficulties involved in linking exposure to putative hazardous substances in environmental and occupational settings to adverse reproductive outcomes, especially success of IVF procedures. We highlight the plausibility of adverse events through animal and cell studies and the application of these results to the interpretation of human data. We consider both the male and female partners since it is essentially their combined contributions of gametes which may be affected by chemicals, which lead to successful outcomes.

Smoking and infertility

Approximately 30% of reproductive age women and 35% of reproductive age men in the United States smoke cigarettes. Substantial harmful effects of cigarette smoke on fecundity and reproduction have become apparent but are not generally appreciated.

Impact of seasonal variation, age and smoking status on human semen parameters: The Massachusetts General Hospital experience

BACKGROUND: To investigate the relationship of human semen parameters with season, age and smoking status. METHODS: The present study used data from subjects recruited into an ongoing cross-sectional study on the relationship between environmental agents and semen characteristics. Our population consisted of 306 patients who presented to the Vincent Memorial Andrology Laboratory of Massachusetts General Hospital for semen evaluation. Sperm concentration and motility were measured with computer aided sperm analysis (CASA). Sperm morphology was scored using Tygerberg Kruger strict criteria. Regression analyses were used to investigate the relationships between semen parameters and season, age and smoking status, adjusting for abstinence interval. RESULTS: Sperm concentration in the spring was significantly higher than in winter, fall and summer (p < 0.05). There was suggestive evidence of higher sperm motility and percent of sperm with normal morphology in the spring than in the other seasons. There were no statistically significant relationships between semen parameters and smoking status, though current smokers tended to have lower sperm concentration. We also did not find a statistically significant relationship between age and semen parameters. CONCLUSIONS: We found seasonal variations in sperm concentration and suggestive evidence of seasonal variation in sperm motility and percent sperm with normal morphology. Although smoking status was not a significant predictor of semen parameters, this may have been due to the small number of current smokers in the study.

Smoking and female fecundity: the effect and importance of study design

This review evaluates the evidence for a link between smoking and female fertility. Twenty-two primary papers and two reviews were found. All but three indicated a detrimental effect of smoking on reproduction despite varying considerably in their approach, definitions used and populations studied. The strength of association is small but statistically significant and a dose response relationship suggests the theory that smoking is causative. Poor design in particular and the failure to assess confounders weakened many studies and should be addressed in future studies.

Smoking and infertility

Approximately 30% of reproductive age women and 35% of reproductive age men in the United States smoke cigarettes. Substantial harmful effects of cigarette smoke on fecundity and reproduction have become apparent but are not generally appreciated.

Early ovarian ageing

Observations from reproductive biology, epidemiology, and clinical assisted reproduction support the hypothesis that the time interval between the onset of accelerated decline of the ovarian reserve and the menopause is more or less fixed. Thus, it is estimated that women who become menopausal by the age of 45 may have experienced an accelerated decline of their fertility before the age of 32. Up to 10% of women in the general population may fall into this category, which has been described as "early ovarian ageing". Because of the long latent phase and predictable natural history, this condition is suitable for screening. High-risk groups include, women with a family history of early menopause. IVF has provided a model for the development of ovarian reserve tests, some of which appear promising as potential screening tools for the detection of early ovarian ageing in asymptomatic women in the general population.

Negative lifestyle is associated with a significant reduction in fecundity

OBJECTIVE

To evaluate the association patterns and quantify the effects of lifestyle on time to pregnancy (TTP).

DESIGN

Observational study.

SETTING

Teaching hospitals in Hull, United Kingdom.

PATIENT(S)

Two thousand and one hundred twelve consecutive pregnant women.

INTERVENTION(S)

A questionnaire inquiring about TTP, contraceptive use, pregnancy planning, previous subfertility/pregnancies, age, and lifestyle characteristics of either partner.

MAIN OUTCOME MEASURE(S)

We compared TTP, conception rates, and relative risk of subfecundity between subgroups with different lifestyle characteristics.

RESULT(S)

We found that TTP was significantly longer if the woman or partner smoked >15 cigarettes/day (P<.001 and.04, respectively), the partner consumed >20 alcohol units/week (P<.001), the woman's body mass index was >25 kg/m(2) (P<.001), their coffee and/or tea intake was >6 cups/day (P=.04), or if they were socially deprived (P<.001). Each of these effects remained unchanged after adjusting for the potential confounders. The relative-risks of subfecundity with each of these variables ranged between 1.4 to 1.9 (1.4 to 3.6 after adjustment). The effects of coital frequency and recreational drug use were insignificant. Couples who had >4 negative lifestyle variables had a sevenfold longer TTP; their conception probabilities fell by 60%, and they were 7.3-fold more likely to be subfecund than those without negative variables.

CONCLUSION(S)

Lifestyle has a significant and cumulative impact on fecundity. Dose-dependent effects occur with smoking, alcohol, and tea/coffee consumption. Appropriate counseling could result in substantial reductions in the referrals for fertility investigations and treatments.

Risk factors for female infertility in an agricultural region

BACKGROUND

Recent studies have suggested that agricultural occupations or exposure to pesticides may impair female fertility.

METHODS

The Fertility Risk Factor Study retrospectively examined agricultural and residential exposures and the risk of female infertility. Cases and controls (N = 322 each) came from women who sought treatment at a large group medical clinic in Wisconsin. Women and their male partners provided information on health, occupational and lifestyle exposures in response to a telephone interview during 1997-2001.

RESULTS

Mixing and applying herbicides 2 years before attempting conception was more common among infertile women (odds ratio [OR] = 27; 95% confidence interval [CI] = 1.9-380), as was the use of fungicides (OR = 3.3; CI = 0.8-13). Residing on a farm, ranch or in a rural area during this time period was protective of female fertility. Households supplied with central Wisconsin groundwater were at less risk for infertility than households using municipal sources (OR = 0.6; CI = 0.4-0.9). Behavioral risk factors included alcohol consumption (OR = 1.8; 1.2-2.5), smoking (1.6; 0.9-2.9), passive smoke exposure (1.8; 1.2-2.5), steady weight gain in adult life (3.5; 2.0-6.1), and having a male partner over the age of 40 (4.5; 1.2-16.3). Drinking 3 or more glasses of milk per day was protective of female fertility (0.3; 0.1-0.7).

CONCLUSION

These results suggest that certain agricultural, residential and lifestyle choices may modify the risk of female infertility.