Cotinine, a major metabolite of nicotine, is detectable in follicular fluids of passive smokers in in vitro fertilization therapy

Association between polycyclic aromatic hydrocarbons and infertility in U.S. women: National Health and Nutrition Examination Survey 2013-2016

Although there is a body of research indicating the potential impact of polycyclic aromatic hydrocarbons (PAHs) exposure on male infertility, the understanding of how PAH might affect female infertility is still limited. This study aimed to evaluate associations of PAHs, both individually and as a mixture, with female infertility using multiple logistic regression, Bayesian kernel machine regression (BKMR), and quantile g-computation (QGC) models based on data from the National Health and Nutrition Examination Survey (NHANES) 2013-2016. The study included 729 female participants. Multiple logistic regression results indicated that there was a significant association between the third tertile of 2-hydroxy fluorene (2-OHFLU) and female infertility, and the OR was 2.84 (95% CI: 1.24-6.53, P value = 0.015) compared with the first tertile after adjusting for the potential covariates. The BKMR model revealed a positive overall trend between mixed PAH exposure and female infertility, particularly when the mixture was at or above the 55th percentile, where 2-hydroxynaphthalene (2-OHNAP) and 1-hydroxypyrene (1-OHPYR) were the primary influences of the mixture. The univariate exposure-response function indicated positive associations between individual PAH exposure, specifically 2-OHNAP, 2-OHFLU, and 1-OHPYR, and female infertility. The QGC model also indicated a positive trend between exposure to a mixture of PAHs and female infertility, although it did not reach statistical significance (OR = 1.33, 95%CI: 0.86-2.07), with 1-OHPYR having the greatest positive effect on the outcome. This study suggested that exposure to PAHs may be associated with female infertility and further research is needed to consolidate and confirm these findings.

Tobacco or marijuana use and infertility: a committee opinion

In the United States, approximately 21% of adults report some form of tobacco use, although 18% report marijuana use. Although the negative impact of tobacco use in pregnancy is well documented, the impact of tobacco and marijuana on fertility and reproduction is less clear. This committee opinion reviews the potential deleterious effects of tobacco, nicotine, and marijuana use on conception, ovarian follicular dynamics, sperm parameters, gamete mutations, early pregnancy, and assisted reproductive technology outcomes. It also reviews the current status of tobacco smoking cessation strategies. This document replaces the 2018 American Society for Reproductive Medicine Practice Committee document entitled Smoking and Infertility: a committee opinion (Fertil Steril 2018).

Prenatal exposure to tobacco and adverse birth outcomes: effect modification by folate intake during pregnancy

BACKGROUND

Fetal exposure to tobacco increases the risk for many adverse birth outcomes, but whether diet mitigates these risks has yet to be explored. Here, we examined whether maternal folate intake (from foods and supplements) during pregnancy modified the association between prenatal exposure to tobacco and with preterm delivery, small-for-gestational age (SGA) births, or neonatal adiposity.

METHODS

Mother-child pairs (n = 701) from Healthy Start were included in this analysis. Urinary cotinine was measured at ~ 27 weeks gestation. Diet was assessed using repeated 24-h dietary recalls. Neonatal adiposity (fat mass percentage) was measured via air displacement plethysmography. Interaction was assessed by including a product term between cotinine (< / ≥ limit of detection [LOD]) and folate (< / ≥ 25th percentile [1077 µg/day]) in separate logistic or linear regression models, adjusting for maternal age, race, ethnicity, education, pre-pregnancy body mass index, and infant sex.

RESULTS

Approximately 26% of women had detectable levels of cotinine. Folate intake was significantly lower among women with cotinine ≥ LOD as compared to those with cotinine < LOD (1293 µg/day vs. 1418 µg/day; p = 0.01). Folate modified the association between fetal exposure to tobacco with neonatal adiposity (p for interaction = 0.07) and SGA (p for interaction = 0.07). Among those with lower folate intake, fetal exposure to tobacco was associated with lower neonatal adiposity (mean difference: -2.09%; 95% CI: -3.44, -0.74) and increased SGA risk (OR: 4.99; 95% CI: 1.55, 16.14). Conversely, among those with higher folate intake, there was no difference in neonatal adiposity (mean difference: -0.17%; 95% CI: -1.13, 0.79) or SGA risk (OR: 1.15; 95% CI: 0.57, 2.31).

CONCLUSIONS

Increased folate intake during pregnancy (from foods and/or supplements) may mitigate the risk of fetal growth restriction among those who are unable to quit smoking or cannot avoid secondhand smoke during pregnancy.

Melatonin prevents oocyte deterioration due to cotinine exposure in mice

Levels of cotinine, a major metabolite of nicotine, have been positively correlated with risks of cigarette smoking-related diseases. Melatonin is synthesized by the pineal gland and has been demonstrated to be beneficial to oocyte maturation due to its antioxidative activity. In this study, we investigated the effects of cotinine on mouse oocyte meiosis and the protective roles of melatonin in vitro and in vivo. The results showed that cotinine exposure caused defects in the first polar body extrusion and reduced parthenogenetic activation in in vitro-matured oocytes. Additionally, cotinine exposure increased the level of oxidative stress, which resulted in aberrant actin distribution, abnormal spindle morphology, chromosome misalignment, and even oocyte aneuploidy. Simultaneously, cotinine exposure decreased the mitochondrial membrane potential and antioxidant gene expression and increased apoptosis-related gene expression. However, all these toxic effects of cotinine could be reversed after the addition of melatonin, and the mechanism may be a decrease in reactive oxygen species production. In conclusion, cotinine causes poor oocyte quality, which could be rescued by melatonin supplementation during meiotic maturation in mouse oocytes.

Structural binding perspectives of a major tobacco alkaloid, nicotine, and its metabolite cotinine with sex-steroid nuclear receptors

Globally, more than a billion people smoke tobacco making it one of the biggest public health problems and a leading risk factor for global deaths. Nicotine, the main alkaloid in tobacco, has been shown to be associated with fertility problems in men and women. The adverse effects of tobacco/nicotine on reproduction have been attributed to deleterious effects on gametes, steroidogenic imbalance, and competitive inhibition of steroid receptors. The present study reports the sex-steroid receptor disrupting potential of nicotine and its major metabolite cotinine against the estrogen receptor-α (ERα), ERβ, androgen receptor (AR), and progesterone receptor (PR). Both ligands bound in the ligand-binding pockets of ERα, ERβ, AR and PR and formed important hydrophobic interactions with different amino-acid residues of receptors. Most of the residues of ERα, ERβ, AR and PR interacting with nicotine and cotinine were common with those of native/bound ligands of the receptors. Interacting amino acids most important for binding of nicotine and cotinine with each receptor were identified by loss in accessible surface area. Amino acids Leucine-346, Leucine-384 and Phenylalanine-404 for ERα; Methionine-336, Phenylalanine-356 and Leucine-298 for ERβ; and Leucine-704 and Leucine-718, respectively for AR and PR, were the most important residues for binding with nicotine and cotinine. Among the four receptors, based on the number of interactions, nicotine and cotinine had greater potential to interfere in the signaling of ERβ. In conclusion, the results suggested that nicotine and cotinine bind and interact with sex-steroid nuclear receptors and have potential to interfere in the steroid hormone signaling resulting in reproductive dysfunction.

Biological effects of nicotine exposure: A narrative review of the scientific literature

The emergence of new tobacco heating products and electronic nicotine delivery systems (ENDS) is changing the way humans are exposed to nicotine. The purpose of this narrative review is to provide a broad overview of published scientific literature with respect to the effects of nicotine on three key health-related areas: 1) cardiovascular risk, 2) carcinogenesis and 3) reproductive outcomes. These areas are known to be particularly vulnerable to the effects of cigarette smoke, and in addition, nicotine has been hypothesized to play a role in disease pathogenesis. Acute toxicity will also be discussed. The literature to February 2019 suggests that there is no increased cardiovascular risk of nicotine exposure in consumers who have no underlying cardiovascular pathology. There is scientific consensus that nicotine is not a direct or complete carcinogen, however, it remains to be established whether it plays some role in human cancer propagation and metastasis. These cancer progression pathways have been proposed in models in vitro and in transgenic rodent lines in vivo but have not been demonstrated in cases of human cancer. Further studies are needed to determine whether nicotine is linked to decreased fertility in humans. The results from animal studies indicate that nicotine has the potential to act across many mechanisms during fetal development. More studies are needed to address questions regarding nicotine exposure in humans, and this may lead to additional guidance concerning new ENDS entering the market.

Cardiovascular, carcinogenic and reproductive effects of nicotine exposure: A narrative review of the scientific literature

The emergence of new tobacco heating products and electronic nicotine delivery systems (ENDS) is changing the way humans are exposed to nicotine. The purpose of this narrative review is to provide a broad overview of published scientific literature with respect to the effects of nicotine on three key health-related areas: 1) cardiovascular risk, 2) carcinogenesis and 3) reproductive outcomes. These areas are known to be particularly vulnerable to the effects of cigarette smoke, and in addition, nicotine has been hypothesized to play a role in disease pathogenesis. Acute toxicity will also be discussed. The literature to February 2019 suggests that there is no increased cardiovascular risk of nicotine exposure in consumers who have no underlying cardiovascular pathology. There is scientific consensus that nicotine is not a direct or complete carcinogen, however, it remains to be established whether it plays some role in human cancer propagation and metastasis. These cancer progression pathways have been proposed in models in vitro and in transgenic rodent lines in vivo but have not been demonstrated in cases of human cancer. Further studies are needed to determine whether nicotine is linked to decreased fertility in humans. The results from animal studies indicate that nicotine has the potential to act across many mechanisms during fetal development. More studies are needed to address questions regarding nicotine exposure in humans, and this may lead to additional guidance concerning new ENDS entering the market.

Ovotoxicity of cigarette smoke: A systematic review of the literature

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

Usefulness of bovine and porcine IVM/IVF models for reproductive toxicology

Women presenting fertility problems are often helped by Assisted Reproductive Techniques (ART), such as in vitro fertilization (IVF) programs. However, in many cases the etiology of the in/subfertility remains unknown even after treatment. Although several aspects should be considered when assisting a woman with problems to conceive, a survey on the patients' exposure to contaminants would help to understand the cause of the fertility problem, as well as to follow the patient properly during IVF. Daily exposure to toxic compounds, mainly environmental and dietary ones, may result in reproductive impairment. For instance, because affects oocyte developmental competence. Many of these compounds, natural or synthetic, are endocrine disruptors or endocrine active substances that may impair reproduction. To understand the risks and the mechanism of action of such chemicals in human cells, the use of proper in vitro models is essential. The present review proposes the bovine and porcine models to evaluate toxic compounds on oocyte maturation, fertilization and embryo production in vitro. Moreover, we discuss here the species-specific differences when mice, bovine and porcine are used as models for human.

Secondhand smoke exposure-induced nucleocytoplasmic shuttling of HMGB1 in a rat premature skin aging model

Secondhand cigarette smoke exposure (SSE) has been linked to carcinogenic, oxidative, and inflammatory reactions. Herein, we investigated whether premature skin aging could be induced by SSE in a rat model, and assessed the cytoplasmic translocation of high mobility group box 1 (HMGB1) protein and collagen loss in skin tissues. Animals were divided into two groups: SSE and controls. Whole body SSE was carried out for 12 weeks. Dorsal skin tissue specimens were harvested for HMGB1 and Mallory's azan staining. Correlations between serum HMGB1 and collagen levels were determined. Rat skin exposed to secondhand smoke lost collagen bundles in the papillary dermis and collagen decreased significantly (p<0.05) compared with control rats. In epidermal keratinocytes, cytoplasmic HMGB1 staining was more diffuse and there were more HMGB1-positive cells after four weeks in SSE compared to control rats. A negative correlation between HMGB1 serum and collagen levels (r=-0.631, p=0.28) was also observed. Therefore, cytoplasmic HMGB1 expression in skin tissues might be associated with skin collagen loss upon the initiation of SSE. Additionally, long-term SSE might affect the appearance of the skin, or could accelerate the skin aging process.

Do cigarette smoke and vitamin E affect the development of endometrial pinopods? An animal study

OBJECTIVES

To study the effects of cigarette smoke and vitamin E on the development of endometrial pinopods.

STUDY DESIGN

Eighteen female and 12 male Swiss albino mice, 12-14 weeks old, with a mean weight of 25g (standard deviation 5g) were used in this study. Female mice were divided into three equal groups. Every day for 10 weeks, mice in Group 1 (control group) received normal saline intraperitoneally; mice in Group 2 were exposed to smoke from 20 cigarettes/day using a smoke machine; and mice in Group 3 were exposed to smoke from 20 cigarettes/day using a smoke machine and also received 50mg/kg vitamin E intraperitoneally. After 10 weeks, vaginal smears were taken from the female mice and they were copulated with the 12 male Swiss albino mice on the day of oestrus. Day 0 was defined as the day on which sperm were detected in the vagina by smear test. Mice were killed at the end of Day 5, which was considered to represent the optimal day for implantation. The uteri were removed and the effects of cigarette smoke and vitamin E on the development of endometrial pinopods were studied using an electron microscope.

RESULTS

The endometrial tissue of the control group appeared morphologically normal, with short microvilli, cytoplasm and pinopods in the form of cytoplasm and cell membrane enlargements in patches. In total, 149 pinopods were counted in the control group using a scanning electron microscope (two histologists performed the analysis and were blinded to each other's findings). In the smoke-exposed group, the cytoplasmic structure was degenerated considerably, and fewer pinopods were counted (n=11). The number of pinopods in mice who were exposed to cigarette smoke and vitamin E (n=67) was significantly higher compared with the cigarette-exposed group (p=0.002), but considerably lower compared with the control group (p=0.002).

CONCLUSION

Smoke exposure led to a significant decrease in the development of endometrial pinopods. Vitamin E, an antioxidant, partially reversed the adverse effects of cigarette smoke. This suggests that cigarettes may have a negative effect on fertility by decreasing the number of pinopods. However, this negative effect can be reduced using vitamin E. More studies should be conducted to support this finding.

In vivo exposure to benzo(a)pyrene induces significant DNA damage in mouse oocytes and cumulus cells

STUDY QUESTION

Does in vivo exposure to benzo(a)pyrene (BaP) induce DNA damage in oocytes and cumulus cells (CCs) in mice?

SUMMARY ANSWER

Significant increases in DNA strand breaks in oocytes and CCs and in BaP-induced DNA adducts in CCs were detected in exposed mice compared with controls.

WHAT IS KNOWN ALREADY

BaP has well-known mutagenic and carcinogenic effects on somatic cells, and is also registered as potential reproductive toxicant by several environmental protection agencies. It has been shown to cause a significant increase in DNA adducts in ovarian tissues; however, to our knowledge, the genotoxic effects of BaP on oocytes and CCs have not been studied to date.

STUDY DESIGN, SIZE, DURATION

Female CD1 mice were exposed to BaP via the oral administration of a single dose of 13 mg/kg body weight (bw); matched controls were exposed to the vehicle only (soya oil). A total of 15 groups of 6 mice (exposed or controls) were sacrificed 2, 4, 6, 15 or 22 days after BaP exposure, and after collection of oviducts, the oocyte-CC complexes (COC) were released.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The alkaline comet assay was used to quantify the DNA breaks in oocytes and CCs; DNA damage was expressed as the Olive Tail Moment (OTM). Immunofluorescent staining was used to quantify BaP-induced DNA adducts in CCs. Fluorescence was expressed as the average grey value (AGVA; arbitrary units). The differences between the exposed and control groups were assessed using analysis of variance (ANOVA) and the non-parametric Mann-Whitney test.

MAIN RESULTS AND THE ROLE OF CHANCE

Higher levels of DNA damage were observed in the oocytes and CCs of BaP-exposed mice than in those of vehicle controls. Significant increases in OTM (mean ± SE) were detected in (i) oocytes from females exposed for 4 (10.5 ± 0.9 versus 3.1 ± 0.4, P < 0.0001) or 6 days before collection (15.6 ± 2.0 versus 3.6 ± 0.9, P < 0.0001) and (ii) CCs from females exposed 2 (6.4 ± 0.6 versus 2.1 ± 0.2, P < 0.0001), 4 (7.8 ± 0.4 versus 2.4 ± 0.1, P < 0.0001) or 6 days before collection (7.3 ± 0.3 versus 3.2 ± 0.5, P < 0.0001) compared with controls. A significant increase in benzo(a)pyrene-7,8-9,10 diol epoxide (BPDE)-DNA adducts and higher AGVA (mean ± SE) scores were observed in CCs from females exposed 2 (6.1 ± 0.3 versus 3.6 ± 0.5, P < 0.0001), 4 (7.5 ± 0.1 versus 3.4 ± 0.1, P < 0.0001) or 6 days before collection (11.6 ± 0.4 versus 3.7 ± 0.1, P < 0.0001) compared with control mice.

LIMITATIONS, REASONS FOR CAUTION

Mice were given one treatment via the oral route because this dose and mode of administration have been shown to induce detectable BPDE-DNA adduct levels in mouse organs and sperm cells. Additional data are needed to assess DNA damage in oocytes and CCs after chronic exposure to BaP in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

To our knowledge, this is the first study examining the in vivo genotoxicity of BaP in oocytes and CCs. We observed significant DNA damage in the oocytes and CCs of mice after acute BaP exposure. BPDE-DNA adducts result directly from BaP metabolism while DNA breaks could result mainly from BPDE-DNA adduct excision and repair and/or through direct genotoxicity from increased reactive oxygen species. These results add new and important insights regarding the recently suggested toxicity of chronic BaP exposure in the ovary.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by a grant (93-CPQ 2012-05) from the DIRRECTE, Provence Alpes Côte d'Azur, France. None of the authors have any conflict of interest to declare.

[Effects of cigarette smoking on female reproduction: from oocyte to embryo (Part I)]

Cigarette smoking is associated with lower fecundity rate, adverse reproductive outcomes and higher risk of IVF failure. Over the last decades, prevalence of smoking among women of reproductive age has increased. The aim of this work was to focus on the knowledge of the effects of cigarette smoking on all reproductive stages, from oocyte to embryo. For each reproductive functions human clinical and experimental studies were analysed in order to find hypothesis and explanations for effects observed. All reproductive functions are targets of smoke compounds and cigarette smoking impairs ovarian reserve, sexual steroids synthesis, Fallopian tubes functions and embryo development, leading to reduced fecundity. Some of smoke compounds were identified in ovarian tissue, in uterine fluid and in the embryo, suggesting direct toxicity.

Human maternal and umbilical cord blood concentrations of polybrominated diphenyl ethers

Polybrominated diphenyl ethers (PBDEs), widely used as flame retardants in commercial products, have become ubiquitous environmental contaminants. Although adult human exposure to PBDEs is well documented, developmental exposure is less well characterized. The objectives of this study were to measure maternal and fetal exposure to nine PBDE congeners and to investigate potential associations with birth weight. PBDE congeners were quantified in maternal serum at 24-28 weeks of pregnancy, delivery, and umbilical cord serum (UCS) by gas chromatography-mass spectrometry (GC/MS/MS). Complete blood sample sets were obtained from 97 pregnant women (mean age 33.1±0.5 years). PBDE-28, -47 and -99 were quantified in all samples tested and PBDE-47 was the most abundant congener measured in both maternal (mid-pregnancy and delivery samples geometric mean=26.9 and 26.9, respectively) and UCS (GM=56.0 ng g(-1) lipid). The UCS concentration for all congeners with the exception of PBDE-153 was higher vs. maternal delivery samples (p<0.001). Only the UCS concentration of PBDE-17 and -99 were significantly associated (β=-49.860, p=0.032, and β=-3.645, p=0.05) with birth weight. However, after adjustment for potential confounders only the association between PBDE-99 and birth weight remained significant (β=-3.951 and p=0.016). We conclude that: the fetus is exposed to PBDEs from at least the second trimester of pregnancy onward; PBDE congeners are higher in UCS compared to maternal serum samples collected at delivery; and that developmental PBDE exposure is potentially associated with lower birth weight.

Cotinine concentrations in follicular fluid as a measure of secondhand tobacco smoke exposure in women undergoing in vitro fertilization: inter-matrix comparisons with urine and temporal variability

We examined the relationship between cotinine measures in follicular fluid (FF) and urine to inform our exposure assessment strategy for an ongoing epidemiological study of secondhand tobacco smoke (STS) exposure and early pregnancy loss. Among subjects undergoing in vitro fertilization (IVF), we compared cotinine levels in paired urine and FF samples from the same women and examined FF cotinine levels over time. We found a weak rank-order relationship (Spearman r<0.2) and poor agreement for classifying nonsmoking individuals as exposed to STS (sensitivity=0.29-0.71; specificity=0.35-0.72) between cotinine concentrations in FF and urine. We observed fair reliability (ICC=0.42-0.52) in FF cotinine concentrations from women undergoing multiple IVF cycles. If available, FF cotinine concentrations may be desired as a biomarker of low-level tobacco smoke exposure over urinary cotinine in studies of early reproduction. Collection of multiple FF samples for cotinine analysis may be needed to accurately represent long-term STS exposure.

Mitochondrial function in the human oocyte and embryo and their role in developmental competence

The role of mitochondria as a nexus of developmental regulation in mammalian oogenesis and early embryogenesis is emerging from basic research in model species and from clinical studies in infertility treatments that require in vitro fertilization and embryo culture. Here, mitochondrial bioenergetic activities and roles in calcium homeostasis, regulation of cytoplasmic redox state, and signal transduction are discussed with respect to outcome in general, and as possible etiologies of chromosomal defects, maturation and fertilization failure in human oocytes, and as causative factors in early human embryo demise. At present, the ability of mitochondria to balance ATP supply and demand is considered the most critical factor with respect to fertilization competence for the oocyte and developmental competence for the embryo. mtDNA copy number, the timing of mtDNA replication during oocyte maturation, and the numerical size of the mitochondrial complement in the oocyte are evaluated with respect to their relative contribution to the establishment of developmental competence. Rather than net cytoplasmic bioenergetic capacity, the notion of functional compartmentalization of mitochondria is presented as a means by which ATP may be differentially supplied and localized within the cytoplasm by virtue of stage-specific changes in mitochondrial density and potential (ΔΨm). Abnormal patterns of calcium release and sequestration detected at fertilization in the human appear to have coincident effects on levels of mitochondrial ATP generation. These aberrations are not uncommon in oocytes obtained after ovarian hyperstimulation for in vitro fertilization. The possibility that defects in mitochondrial calcium regulation or bioenergetic homeostasis could have negative downstream development consequences, including imprinting disorders, is discussed in the context of signaling pathways and cytoplasmic redox state.

Effects of cigarette smoking on reproduction

BACKGROUND Cigarette smoking is associated with lower fecundity rates, adverse reproductive outcomes and a higher risk of IVF failures. Over the last few decades, prevalence of smoking among women of reproductive age has increased. This review focuses on current knowledge of the potential effects of smoke toxicants on all reproductive stages and the consequences of smoke exposure on reproductive functions. METHODS We conducted a systematic review of the scientific literature on the impact of cigarette smoking and smoke constituents on the different stages of reproductive function, including epidemiological, clinical and experimental studies. We attempted to create hypotheses and find explanations for the deleterious effects of cigarette smoke observed in experimental studies. RESULTS Cigarette smoke contains several thousand components (e.g. nicotine, polycyclic aromatic hydrocarbons and cadmium) with diverse effects. Each stage of reproductive function, folliculogenesis, steroidogenesis, embryo transport, endometrial receptivity, endometrial angiogenesis, uterine blood flow and uterine myometrium is a target for cigarette smoke components. The effects of cigarette smoke are dose-dependent and are influenced by the presence of other toxic substances and hormonal status. Individual sensitivity, dose, time and type of exposure also play a role in the impact of smoke constituents on human fertility. CONCLUSIONS All stages of reproductive functions are targets of cigarette smoke toxicants. Further studies are necessary to better understand the deleterious effects of cigarette smoke compounds on the reproductive system in order to improve health care, help to reduce cigarette smoking and provide a better knowledge of the molecular mechanisms involved in reproductive toxicology.

Levels of DNA adducts in the blood and follicular fluid of women undergoing in vitro fertilization treatment and its correlation with the pregnancy outcome

This study is designed to investigate the impact of DNA damage on pregnancy and fertilization rate outcome in a sub-sample of women undergoing IVF treatment. Blood and follicular fluid samples (n = 60) were analyzed for DNA adducts. While no BPDE-DNA adducts were detected, other unknown lipophilic adducts were seen in blood and follicular fluid. Women who failed to achieve pregnancy had higher DNA adducts in follicular fluid than those who succeeded (p < 0.05). Follicular fluid cotinine levels were associated with DNA adduct levels in blood and follicular fluid (p < 0.05). Evaluation of DNA damage resulting from oxidative stress could have a role in predicting IVF success rate.

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.

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.

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.

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.

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.

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.

Decreased fertility in mice exposed to environmental air pollution in the city of Sao Paulo

It has largely been shown that air pollution can affect human health. Effects on human fertility have been shown mainly in males by a decrease in semen quality. Few studies have focused on the environmental effects on female fertility. The aim of the present study was to analyze the effects of air pollution in the city of Sao Paulo on mouse female fertility. Four groups of female Balb/c mice were placed in two chambers 10 days (newborn) or 10 weeks (adults) after birth. Mice were maintained in the chambers 24 h a day, 7 days a week, for 4 months. The first chamber received air that had passed through an air filter (clean chamber) and the second received ambient air (polluted chamber). We measured PM10 and NO2 inside both chambers. Mice belonging to the adult groups were bred to male mice after living for 3 months inside the chambers. The newborn groups mated after reaching reproductive age (12 weeks). After 19 days of pregnancy the numbers of live-born pups, reabsorptions, fetal deaths, corpora lutea, and implantation failures were determined. PM10 and NO2 concentrations in the clean chamber were 50% and 77.5% lower than in the polluted chamber, respectively. Differences in fertility parameters between groups were observed only in animals exposed to air pollution at an early age (10 days after birth). We observed a higher number of live-born pups per animal in the clean chamber than per animal from the polluted chamber (median=6.0 and 4.0, respectively; P=0.037). There was a higher incidence of implantation failures in the polluted group than in the clean group (median=3.5 and 2.0, respectively; P=0.048). There were no significant differences in the other reproductive parameters between groups. These results support the concept that female reproductive health represents a target of air pollutants.

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 Nicotine on Human Luteal Cells In Vitro: A Possible Role on Reproductive Outcome for Smoking Women1

We investigated the effect of nicotine and its methylated metabolite, N-methyl-nicotine (M-nicotine), on human luteal cells by measuring release of progesterone and prostaglandins (PGs) from cultured cells and by testing gene expression of vascular endothelial growth factor (VEGF), an angiogenic factor strictly involved in luteal pathophysiology. Primary cultures of human luteal cells were treated for 24 h with nicotine and M-nicotine (from 10(-6) to 10(-11) M) either alone or combined with hCG (25 ng/ml); progesterone and PGs were assayed in the culture medium. In another group of experiments, luteal cells were treated for 24 h with nicotine and M-nicotine (10(-7) M) to perform reverse transcriptase-polymerase chain reaction on VEGF mRNA. Nicotine and M-nicotine negatively affected basal luteal steroidogenesis at all tested concentrations, but neither was able to affect hCG-induced progesterone release. Both substances were able to significantly increase PGF2alpha release from luteal cells, with a dose-related efficacy for M-nicotine. On the contrary, PGE2 release was significantly inhibited by both nicotine and its metabolite. Finally, nicotine was able to increase VEGF mRNA expression significantly, whereas M-nicotine was not. In conclusion, nicotine and M-nicotine can induce a sort of luteal insufficiency by inhibiting progesterone release, probably through modulation of the PG system.

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.

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.

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.

Perivitelline space: does it play a role in blocking polyspermy in mammals?

The perivitelline space of mammalian oocytes changes in size and composition during preimplantation development. Often overlooked in the past, this space contains a hyaluronan-rich extracellular matrix prior to fertilization and a cortical granule envelope following release of the cortical granules at fertilization. The hyaluronan-containing matrix of unfertilized oocytes is well developed in some species such as opossums and humans but is scant in rodents including the hamster and mouse. The significance of the hyaluronan-rich matrix, which attaches to the plasma membrane of the oocytes, is not fully understood. However, hyaluronan, which can inhibit membrane fusion, is present in the perivitelline space (PVS) of unfertilized oocytes and must be negotiated by the fertilizing sperm. Following fertilization, the cortical granule envelope forms as the cortical granules disperse, thereby causing the PVS to increase significantly in size. Calcium is important in the dispersion of the cortical granules following exocytosis. Once formed, the cortical granule envelope in some species is about the same thickness as the zona pellucida, but it is not readily visualized unless it is stained with fluorescent probes or examined ultrastructurally after following stabilization with ruthenium red. The envelope contains proteins that remain in the PVS until the time of blastocyst hatching. Although little work has been done on the functions of the cortical granule envelope, several studies are consistent with the idea that it plays a role in blocking polyspermy. While nicotine increases polyspermy in sea urchins, its effects on polyspermy in human smokers have not been characterized, but could be addressed in human in vitro fertilization labs.

Variation of serum and urine cotinine in passive and active smokers and applicability in preconceptional smoking cessation counseling

This study assessed the applicability of serum and urine cotinine as a biochemical marker of self-reported smoking habits for use in a preconceptional smoking cessation program. The variation of serum and urine cotinine over the course of the day was investigated in a sample of 21 smokers and 8 passive smokers who reported their smoking habits and exposure to smoke daily in a questionnaire for 10 consecutive days. Blood and urine samples were collected on two sampling days, 1 week apart. Both serum and urine cotinine assay could distinguish between passive and active smokers, but not between higher categories of smokers (10-19 and > or = 20 cigarettes per day) due to significant intersubject overlap. In serum, no significant differences were found between morning and afternoon cotinine concentrations on either day, in contrast to urine cotinine (with lower excretions observed in the morning). An overall coefficient of variation of 22% was observed for both specimens in smokers. Because serum cotinine is subject to lower variability over the course of the day, it is more practical for use in a clinical setting where appointments are scheduled throughout the day in order to confirm smoking status.

The miseries of passive smoking

Passive smoking is defined as an involuntary exposure to a combined but diluted cigarette sidestream smoke (SS, gas and particle phases that are evolved from the smoldering end of a cigarette while the smoker is not puffing) and the exhaled smoke from smokers. SS contains numerous cytotoxic substances such as polycyclic aromatic hydrocarbons (PAHs), aromatic amines, nitrosamines, heavy metals, poisonous gases, pesticide residues, and radioactive elements in quantities much higher than those found from the cigarette mainstream smoke (MS) which is puffed by smokers. Passive smoking is found to be the cause of death from cancers and cardiac disease. Furthermore, it damagingly involves reproductive organs, the nervous system, genetic materials, and is particularly hazardous to mother and child during pregnancy and to those with a history of asthma, chronic infections, induced or earned immune deficiency, or predisposed susceptibility.

Cigarette smoking and the risk of male factor subfertility: minor association between cotinine in seminal plasma and semen morphology

OBJECTIVE

To evaluate the impact of cigarette smoking on male factor subfertility and the semen parameters of sperm count, motility, and morphology by questionnaire and determination of the cotinine concentrations in blood and seminal plasma of fertile and subfertile males.

DESIGN

Case-control study of 107 fertile and 103 subfertile males who provided a standardized blood and semen specimen and completed a self-administered questionnaire about their smoking habits.

SETTING

Outpatient fertility clinic of the University Medical Centre St. Radboud, Nijmegen, The Netherlands.

PATIENT(S)

One hundred seven fertile and 103 subfertile males.

INTERVENTION(S)

Vena puncture and semen collection.

MAIN OUTCOME MEASURE(S)

Blood and seminal plasma cotinine levels in relation to semen parameters.

RESULT(S)

A higher frequency of cigarette smoking was observed in subfertile males than in fertile males, with an odds ratio of 1.7 (95% confidence interval, 0.9-3.2). The self-reported number of cigarettes smoked per day correlated with the cotinine concentrations in blood and seminal plasma for both groups. A small but statistically significant correlation was found between cotinine concentrations in seminal plasma and the percentage of abnormal sperm morphology, but not for other semen parameters (r(s) = 0.19).

CONCLUSION(S)

Although the mechanism of the toxicity of cotinine on sperm morphology is not clear, this study indicates only a minor effect of cigarette smoking on male factor subfertility, which is probably due to compounds in cigarette smoke other than nicotine (cotinine).

Delayed conception and active and passive smoking. The Avon Longitudinal Study of Pregnancy and Childhood Study Team

OBJECTIVE

To determine whether passive as well as active smoking by women or smoking by men is associated with delayed conception, after adjustment for confounding factors.

DESIGN

Population study of couples expecting a baby. Logistic regression was performed to identify factors associated with delayed conception.

SETTING

The Avon Health Authority area, United Kingdom.

PATIENT(S)

All couples expected to deliver between April 1991 and December 1992.

INTERVENTION(S)

Questionnaires administered early in pregnancy.

MAIN OUTCOME MEASURE(S)

Time taken to conceive, categorized as <6 months, 6-11 months, 1-3 years, and >3 years.

RESULT(S)

After correction for confounding factors, delayed conception was statistically significantly associated with both active smoking by the woman (odds ratio [OR] 1.23 [95% CI 0.98-1.49] for > 6 months and 1.54 [95% CI 1.19-2.01] for >12 months) and her exposure to passive smoking (OR 1.17 [95% CI 1.02-1.37] and 1.14 [95% CI 0.92-1.42]) compared with women with no exposure to tobacco smoke (referent). Heavy smoking by men was independently associated with delayed conception. In active smokers, the effect increased with the number of cigarettes.

CONCLUSION(S)

Smoking by men and passive and active smoking by women are associated with delayed conception.

The effect of smoking on oocyte quality and hormonal parameters of patients undergoing in vitro fertilization-embryo transfer

PURPOSE

The aim of the present study was to investigate the influence of smoking on different parameters such as oocyte count, embryo score, and basal hormone values within the scope of in vitro fertilization-embryo transfer (IVF-ET).

METHODS

Eight hundred thirty-four women undergoing IVF-ET treatment were classified as smokers or nonsmokers on the basis of questionnaires. Additionally, we divided them into three groups according to their stimulation protocol--"combined stimulation" [I; clomiphene citrate plus human menopausal gonadotropin (hMG)], "ultrashort" [II; gonadotropin releasing hormone agonist (GnRHa) plus hMG or follicle-stimulating hormone (FSH)], and "long downregulation protocol" (III)--and further classified again as smokers or nonsmokers within the groups.

RESULTS

In general, smoking patients were significantly (P = 0.0195) younger than nonsmokers and showed a significantly (P = 0.0379) lower embryo score and a tendency (P = 0.0931) to produce fewer oocytes. There was no significant difference concerning the number of normally or pathologically fertilized and transferred oocytes and embryos suitable for cryopreservation. Women who smoked had significantly (P = 0.0112) higher basal 17-beta-estradiol (E2), luteinizing hormone (LH) (P = 0.0001), and dehydroepian-drosteronesulfate (DHEAS) (P = 0.0039) levels, but their basal human prolactin (HPRL) levels were significantly (P = 0.0033) lower than those of nonsmokers. According to the stimulation protocol used, we found the following results. Smoking patients in group I showed a significantly (P = 0.023) lower embryo score and produced fewer oocytes (P = 0.0113), with fewer of them being fertilized (P = 0.0072) and transferred (P = 0.0067). Women who smoked had significantly (P = 0.0002) higher basal LH levels, but their HPRL levels were significantly (P = 0.031) lower than those of nonsmokers. Furthermore, they had a thinner endometrium on the day of embryo transfer (P = 0.0366). In group II we measured significantly elevated basal E2 levels (P = 0.0089) and higher LH values (P = 0.0092) in smokers. Group III showed a trend (P = 0.0565) toward lower HPRL values in smokers.

CONCLUSIONS

Although the fertilization rate of oocytes and the pregnancy rate were not significantly different between smokers and nonsmokers, we found significantly alterated hormonal parameters and negatively influenced oocyte parameters, particularly after clomiphene stimulation. So we might consider using only GnRHa protocols for smoking patients. Additionally, we advise our patients to stop smoking before an IVF-ET treatment because of the complex effects of smoking on the reproductive and hormonal system.

The Graafian follicle is a site of L-ascorbate accumulation

PURPOSE

Our purpose was to evaluate the L-ascorbate level in human preovulatory follicular fluid and to quantify the blood/follicle gradient for vitamin C. The effect of smoking on the follicular L-ascorbate concentration was studied. The correlations were tested between follicular L-ascorbate and follicle size and oocyte maturity.

METHODS

In 65 women undergoing in vitro fertilization, samples of follicular fluid and blood serum were collected. Biochemical analyses included L-ascorbate determinations by a colorimetric method and cotinine measurements by a radioimmunoassay.

RESULTS

The average follicular fluid:serum ratio for L-ascorbate was 1:68. Ascorbate levels in follicular fluid and serum were significantly correlated. The follicular L-ascorbate level did not correlate with the follicle size and the oocyte maturity grade. Insignificantly lowered follicular L-ascorbate levels were observed in smokers.

CONCLUSIONS

The extracellular compartment of the Graafian follicle is a site of an ascorbate accumulation. Exposure to tobacco smoke does not significantly diminish the intrafollicular pool of L-ascorbate.

Interovarian differences in levels of cotinine, a major metabolite of nicotine, in women undergoing IVF who are exposed to cigarette smoke

PURPOSE

Our purpose was to determine whether there is variation in levels of follicular fluid (FF) cotinine between the two ovaries of women undergoing IVF-ET who are exposed to cigarette smoke.

METHODS

In 61 women, there were two to four determinations of FF continine levels for each of two follicles, one from each ovary. For each woman a t test for significant difference between the means of both ovaries was done to test for interovarian variation.

RESULTS

Thirty-seven nonsmokers, 8 passive smokers, and 16 active smokers differed greatly (P < 0.0001) in mean FF cotinine levels: 13.0, 91.1, and 420.3 ng/ml, respectively. Fourteen women had significant differences, at the P = 0.025 level or below, between their two ovaries. Five of them had differences significant at the 0.001 level. Even so, the correlation between the cotinine levels of the two ovaries was high.

CONCLUSIONS

Cotinine uptake between the two ovaries of a woman may differ approximately one-fourth of the time. In spite of these differences, the overall correlation between ovaries is high. The clear distinction in levels of FF cotinine among active, passive, and nonsmokers demonstrates the reliability of FF cotinine testing. Detection of cotinine in a large proportion of nonsmokers shows how pervasive nicotine is in the environment.

Smoking and in vitro fertilization: a meta-analysis

PURPOSE

Including our own data and seven relevant publications from the literature, this meta-analysis aimed to establish the influence of the status of female smokers on the clinical pregnancy rate after the first attempt at in vitro fertilization-embryo transfer (IVF-ET).

METHODS

We started to collect information about our own patient's smoking habits in January 1996 to evaluate prospectively the influence on IVF success. Information regarding 799 patients (607 nonsmokers and 192 smokers) was obtained. Additionally we retrieved seven relevant publications from the unabridged MEDLINE 1982-1996. They were recalculated to first cycles, because from a biometrical point of view, only the results of the first IVF cycle are really well comparable, as the number of necessary IVF cycles always correlates with the number of pregnancies. These data were compared in the nonparametric sign test according to Dixon-Mood and calculated as relative success ratios, defined as the quotient of the probability of IVF-ET success of nonsmokers divided by that of smokers for each publication.

RESULTS

This meta-analysis, based on a total of 2314 first IVF-ET treatments, showed that almost twice as many IVF-ET cycles were needed for smokers as for nonsmokers to become pregnant. For the success quotient, we obtained a ratio of 1.79, with an associated 95% confidence interval of from 1.24 to 2.59. The total analysis shows, with a P value of less than 0.01, significantly higher pregnancy rates (21%) in nonsmokers compared to smokers (14%).

CONCLUSIONS

Based on the analyzed data there exists--from a statistical point of view--a significant negative effect on the chances of success for smokers to become pregnant compared to nonsmokers.

Immunodetection of cotinine protein in granulosa-lutein cells of women exposed to cigarette smoke

OBJECTIVE

To detect immunoreactivity to cotinine protein, a major metabolite of nicotine, in granulosa-lutein cells from patients exposed to cigarette smoke, as measured by levels of cotinine in follicular fluid (FF) samples.

DESIGN

Controlled immunocytochemical study.

SETTING

Hospital IVF-ET program treating infertile patients.

PATIENT(S)

Twenty-eight women classified by self-reported smoking habits: active smokers (n = 17), passive smokers (n = 4), and nonsmokers (n = 7).

INTERVENTION(S)

Ovarian hyperstimulation.

MAIN OUTCOME MEASURE(S)

Grades of immunostaining intensity were assessed in granulosa-lutein cells. Patient scores of cell immunostaining were calculated and regressed on levels of FF cotinine.

RESULT(S)

Cotinine levels in FF were higher in active smokers than in passive smokers or nonsmokers. Cotinine immunostaining was visualized in the nucleus and cytoplasm of granulosa-lutein cells. Mean grades and mean scores of immunostaining intensity were higher in active smokers than in passive smokers or nonsmokers. There was a strong positive correlation between scores of cell immunostaining and FF cotinine levels.

CONCLUSION(S)

The association between cotinine expression in granulosa-lutein cells and FF cotinine provides reliable evidence for a dose-related effect. This constituent of cigarette smoke appears to interact directly with and incorporate into these ovarian cells. Our approach seems useful for monitoring ovarian exposure to environmental toxins.