Associations between follicular fluid trace elements and ovarian response during in vitro fertilization.

INTRODUCTION: Exposure to trace elements has been associated with ovarian response in experimental studies. We conducted a hypothesis-generating study of associations between ovarian follicular fluid (FF) trace elements and measures of ovarian response among women using in vitro fertilization (IVF). METHODS: We collected ovarian FF specimens from 56 women. We determined concentrations (µg/L) of 11 trace elements using inductively coupled plasma-tandem mass spectrometry. We estimated associations between women's FF trace elements per interquartile range difference, and measures of ovarian response using linear (peak estradiol (E2), baseline anti-mullerian hormone (AMH), and follicle stimulating hormone (FSH)) and negative binomial (baseline antral follicle count (AFC) and oocyte count) regression, adjusting for confounding factors. We used principal component analysis (PCA) to estimate the associations of the FF trace elements mixture. We also explored FF oxidative stress enzymes as causal mediators of the associations. RESULTS: Higher FF cobalt was associated with greater peak E2 (mean difference = 351.48 pg/mL; 95%CI: 21.76, 724.71) and AFC (rate ratio = 1.14; 95%CI: 1.01, 1.28), and higher FF copper was associated with greater peak E2 (mean difference = 335.66 pg/mL; 95%CI: 81.77, 753.08) and oocyte count (rate ratio = 1.19; 95%CI: 1.02, 1.43). Higher FF mercury was also associated with greater peak E2 (mean difference = 410.70 pg/mL; 95%CI: 61.90, 883.39). Higher FF lead was associated with lesser AFC (rate ratio = 0.85; 95%CI: 0.73, 0.98). Using PCA, the mixture of Sr, Hg, and As was associated with higher peak estradiol, AFC, and oocyte count. FF glutathione peroxidase, paraoxonase, and arylesterase activities were inconsistent mediators of the associations, but the effect estimates were imprecise. CONCLUSION: Our results suggest that essential and non-essential trace elements in FF were associated with ovarian response during IVF.

Exploratory cohort study into underlying mechanism of differences in estrogen metabolism between Asian and Caucasian women during assisted reproductive technology treatment.

Objective: Explore whether racial differences in prevalence of CYP1A2∗1F polymorphism underlies estrogen metabolism differences among Asians and Caucasians. Design: Prospective cohort study. Setting: University-based fertility practice. Patients: Asian or Caucasian patients who underwent ovarian stimulation (OS) or programmed cycle frozen embryo transfer (FET) between October 2019 and April 2021. Interventions: None. Main Outcome Measures: Trigger-day serum E2 per oocyte retrieved in OS cycles, and E2 on day of lining check in FET cycles. Results: Seventy-one participants were enrolled, 55 in OS group (29 Caucasian and 26 Asian) and 16 in FET group (10 Caucasian and 6 Asian). Peak E2 per oocyte retrieved in the OS group (n = 48) differed by race, with significantly lower levels in Caucasians compared with Asians (177.5 ± 64.2 vs. 261.1 ± 139.5 pg/mL). Prevalence of CYP1A2∗1F polymorphism did not significantly differ by race. Compared using Kruskal-Wallis test, peak E2 per oocyte retrieved did not differ by CYP1A2∗1F genotype. In multivariate linear regression model, adjusting for body mass index, caffeine intake, and self-reported race, there remained no significant correlation. In FET group, serum E2 on day of lining check was also not significantly different by CYP1A2∗1F genotype. Conclusions: Although a consistent difference in serum E2 between Asians and Caucasians undergoing OS was noted, the CYP1A2∗1F polymorphism is unlikely the primary driver of this difference.

Toxic elements in follicular fluid adversely influence the likelihood of pregnancy and live birth in women undergoing IVF.

STUDY QUESTION: Are follicular fluid (FF), arsenic (As), mercury (Hg), cadmium (Cd) and lead (Pb) concentrations associated with IVF outcomes among women undergoing IVF? SUMMARY ANSWER: There was a non-linear association between higher FF Hg concentration and a lower likelihood of biochemical pregnancy and live birth. Higher FF Pb concentration was also associated with a lower probability of live birth. WHAT IS KNOWN ALREADY: Previous research suggests that toxic elements may affect fertility among couples conceiving with and without assistance. However, the results have been inconsistent, possibly related in part to exposure misclassification. Very few studies have used ovarian FF to measure toxic elements, as it requires an invasive collection procedure, yet it may offer a more accurate estimate of a biologically effective dose than blood or urine. STUDY DESIGN SIZE DURATION: This is a prospective study of 56 women undergoing IVF, from October 2015 to June 2017. FF was collected for analysis on the day of oocyte retrieval. PARTICIPANTS/MATERIALS SETTING METHODS: As, Cd, Hg and Pb were determined in 197 FF specimens, using inductively coupled plasma tandem mass spectrometry. FF glutathione peroxidase, glutathione reductase, total glutathione-S-transferase, superoxide dismutase, arylesterase and paraoxonase (PON1p) activities were measured using kinetic enzyme assays. MAIN RESULTS AND THE ROLE OF CHANCE: Non-linear associations were detected, in which the probabilities of biochemical pregnancy (P = 0.05) and live birth (P = 0.05) were lower in association with FF Hg greater than ∼0.51 µg/l Hg, adjusted for age, race, cigarette smoking and recent seafood consumption. Higher FF Pb was also associated with a lower likelihood of live birth (relative risk (RR) = 0.68, 95% CI: 0.46, 1.00; P = 0.05). We also found a suggestive, although imprecise, antagonizing mediating effect of PON1p activity on the association between FF Pb and live birth (-28.3%; 95% CI: -358%, 270%). LIMITATIONS REASONS FOR CAUTION: The results should be interpreted judiciously given the limited sample size and difficulty accounting for correlated data in generalized additive models and mediation analyses. Additionally, women undergoing IVF are highly selected with respect to age and socioeconomic status, and so the generalizability of the results may be limited. WIDER IMPLICATIONS OF THE FINDINGS: Overall, the results suggest that FF Hg was associated with a lower likelihood of biochemical pregnancy and live birth, with a potential threshold effect, and that higher FF Pb was associated with a lower probability of live birth. These results may help to guide clinical recommendations for limiting the exposure of patients to Hg and Pb and ultimately improve IVF success rates. STUDY FUNDING/COMPETING INTERESTS: This work was funded in part by the National Institute of Environmental Health Sciences (NIEHS), grant number 1R56ES023886-01, to the University at Albany (M.S.B.), and in part by the National Institute of Environmental Health Sciences (NIEHS), grant number 1U2CES026542-01, to the Wadsworth Center (P.J.P.). The authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.

Trace element analysis of human seminal plasma: A cautionary tale of preanalytical variation and use of non-traditional matrices in human biomonitoring studies.

Ensuring harmonization of (ultra-)trace element measurements in non-traditional matrices is a particular analytical challenge that is highlighted in this work for seminal plasma as part of the developmental core at the Wadsworth Center Human Health Exposure Analysis Resource Targeted Laboratory. Seminal plasma was collected from 39 male partners of women undergoing in vitro fertilization and analyzed by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) following deproteinization with concentrated HNO3. Validation was accomplished using: 1) two aqueous NIST SRMs; 2) a seminal plasma QC pool, characterized via standard additions; 3) standard additions on a subset of samples; and 4) sample duplicates. Agreement with NIST certified or reference values were obtained to within ±15% for the SRMs, and agreement between aqueous calibration values and standard additions values agreed to within ±10-20% for all elements. Standard additions of seminal plasma samples revealed varying matrix effects for Cu and Cr that were not found for the pooled samples. Duplicate analyses agreed to within ±10-30% depending on element. A potential source of contamination in colloidal silica used for processing seminal plasma was identified that requires further study. Comparisons with literature indicate lack of consensus for As, Cd, Cr, Mn, Pb, and V content in seminal plasma. Further work is needed to improve harmonization of future studies.

Variability of essential and non-essential trace elements in the follicular fluid of women undergoing in vitro fertilization (IVF).

Both essential and non-essential elements have been associated with female reproductive function in epidemiologic investigations, including among IVF populations. To date, most investigators have used blood or urine to assess biomarkers of exposure, with few employing ovarian follicular fluid (FF). FF may offer a more direct "snapshot" of the oocyte microenvironment than blood or urine, however previous studies report follicle-to-follicle variability in FF constituents that may contribute to exposure misclassification. Our objectives were to investigate sources of trace element variability, to estimate FF biomarker reliability among women undergoing IVF (n = 34), and to determine the minimum number of follicles required to estimate subject-specific mean concentrations. We measured As, Hg, Cd, Pb, Cu, Mn, Se, and Zn in FF samples using inductively coupled plasma tandem mass spectrometry. Inter-subject (between-women) variability contributed most of the variability in FF element concentrations, with ovarian, follicular, and analytical as smaller sources of variability. The proportion of variability attributable to sources between-follicles differed by age, body mass index (BMI), race, and cigarette smoking for Cu, Se, and Zn, by BMI and cigarette smoking for As, by primary infertility diagnosis for Hg, Cu, Se, and Zn, and by ovarian stimulation protocol for Mn and Se. Four to five individual follicles were sufficient to estimate subject-specific mean Cu, Se, and Zn concentrations, while >14 were necessary for As, Hg, Cd, Pb, and Mn. Overall, our results suggest that FF is a suitable source of biomarkers of As and Hg exposure in ovarian follicles. Although limited in size, our study offers the most comprehensive exploration of biological variation in FF trace elements to date and may provide guidance for future studies of ovarian trace element exposures.

A pilot investigation of couple-level phthalates exposure and in vitro fertilization (IVF) outcomes.

Phthalates are reproductive toxicants in experimental animal studies and exposure has been associated with infertility in human populations, although the results have been inconsistent. To help to address the data gap, we conducted a hypothesis-generating investigation of associations between urinary phthalate metabolites and reproductive outcomes among women (n = 56) and their male partners (n = 43) undergoing in vitro fertilization (IVF). Urine was collected from participants on the day of oocyte retrieval. Samples were analyzed for a series of phthalates, MEP, MBP, MPP, MHxP, MEHP, MEHHP, MECPP, MiNP, MiDP, MCHP, and MBzP, using liquid chromatography-tandem mass spectrometry. We employed Poisson regression with robust variance estimation to estimate associations between urinary phthalate levels and biochemical pregnancy and live birth, adjusted for partner's concentration and confounding factors. Doublings in women's MBP (relative risk (RR) = 0.32, 95 % CI: 0.13, 0.78), and men's MEHP (RR = 0.28, 95 % CI: 0.09, 0.83), were associated with a lower likelihood for pregnancy. Doublings in women's (RR = 0.08, 95 % CI: 0.01, 0.67) and men's (RR = 0.13, 95 % CI: 0.02, 0.92) MHxP were associated with a lower likelihood of live birth. Our results suggest that phthalate exposure may impact IVF outcomes, and underscore the importance of including male partners when investigating the impact of phthalate exposure on IVF. These results also suggest that clinical recommendations should include male partners for limiting phthalate exposure. Still, a larger and more comprehensive investigation is necessary to more definitively assess the risks.

Seafood consumption is associated with higher follicular fluid arsenic (As) and mercury (Hg) concentrations in women undergoing in vitro fertilization (IVF).

Human exposure to non-essential toxic metals such as cadmium (Cd), mercury (Hg), and lead (Pb), and metalloids such as arsenic (As) commonly occurs through diet. Toxic trace element exposures have been reported in association with fertility and fecundity in epidemiologic studies even at low to moderate levels. While most previous studies employed blood and urine biomarkers of exposure, few have assessed toxic trace elements in ovarian follicular fluid (FF), which surrounds the developing oocyte and hence may better reflect concentrations potentially affecting reproductive outcomes. Our objective was to identify dietary predictors of FF toxic trace elements in n = 56 women (mean age: 38.3 years) undergoing in vitro fertilization (IVF) at the University of California at San Francisco. We determined As, Hg, Cd, and Pb in 197 FF specimens, collected on the day of oocyte retrieval, using inductively coupled plasma tandem mass spectrometry. A comprehensive food frequency questionnaire was used to assess the weekly and annual dietary "patterns" of participants. Consumption of specific seafood items and turkey were correlated with individual FF toxic trace elements. We also found that each unit higher seafood consumption in the past week dominated by mollusks, shrimp, and bass was associated with 60% higher FF As (95% confidence interval (CI): 25%, 105%) and FF Hg (95%CI: 7%, 136%) concentrations. Higher annual seafood consumption dominated by urchin, crab, and trout was associated with 16% higher FF As (95%CI: -2%, 38%) and 31% higher FF Hg (95%CI: 7%, 60%) concentrations per unit intake. No associations were noted between diet and Cd and Pb levels in FF. Overall, our results suggest that higher seafood consumption contributes to elevated levels of As and Hg in FF. These findings are consistent with previous IVF studies that assessed toxic trace element exposures in blood and urine. To our knowledge, this is the first study to report that diet might be a source of As, Hg, Cd, and Pb in FF.

Sources of exposure to urinary phthalates among couples undergoing infertility treatment.

Phthalates have been implicated as reproductive toxicants in animal models and in human populations. This study examined associations between potential exposure sources and urinary phthalate metabolite concentrations among women (n = 56) and their male partners (n = 43) undergoing in vitro fertilization (IVF). On the day of oocyte retrieval, participants provided urine samples and completed questionnaires detailing use of personal care products (PCPs), and consumption of medications, foods, and beverages in the preceding 24 h. Urine was analyzed for MEP, MBP, MPP, MHxP, MEHP, MEHHP, MECPP, MiNP, MiDP, MCHP, and MBzP, via liquid chromatography-tandem mass spectrometry. We employed principal component analysis (PCA) to summarize exposure sources and regression models to estimate associations between exposure patterns and urinary phthalate metabolites, adjusted for confounding variables. Among women, application of more body washes and eye creams, and consumption of more supplements, was associated with greater urinary MECPP [relative difference = 1.36 (95% CI: 1.28, 1.45)] and the molar sum of DEHP metabolites, including MEHP, MEHHP, and MECPP [∑DEHP; 1.26 (95% CI: 1.17, 1.34)]. Among men, consumption of more supplements and allergy medications was associated with greater urinary MECPP, MEHHP, and ∑DEHP [relative difference = 1.13 (95% CI: 1.02, 1.23)] concentrations. Identifying differences in sources of phthalate exposure may help clinicians to intervene to reduce exposure as part of a comprehensive strategy to help improve IVF outcomes.

Prevalence of Partial Hydatidiform Mole in Products of Conception From Gestations With Fetal Triploidy Merits Reflex Genotype Testing Independent of the Morphologic Appearance of the Chorionic Villi.

Diagnosis of first-trimester partial mole is challenging as the key morphologic features may not be well-developed and may overlap with those of a nonmolar gestation harboring a cytogenetic disorder or degenerative changes. Genotype testing has emerged as the reference tool to distinguish partial mole (diandric triploid genotype) from its nonmolar mimics. However, observer variation in defining the minimum threshold of how much morphologic alteration is required to trigger genotype testing may result in a subset of partial moles that go undetected. We hypothesized that the results of fetal aneuploidy testing performed for prenatal screening or evaluation of miscarriage may assist with triggering molecular testing in the evaluation of products of conception, specifically if fetal triploidy is detected. Gestations with fetal triploidy are either a partial mole (diandric triploidy) or are nonmolar (digynic triploidy). The aims of this study were to define the prevalence of partial mole in 20 products of conception specimens with known fetal triploidy by performing genotype testing and then to determine how well established morphologic criteria for partial mole correlate with the genotype results in this setting. Genotype testing demonstrated that 65% (13/20) were a partial mole and the remainder were nonmolar digynic triploid gestations. Most partial moles were under 9 weeks gestational age and, as expected, lacked classic well-developed morphologic features. Nearly a third (4/13) of the partial moles were originally interpreted as normal or nonmolar gestations with minimal abnormalities that did not merit molecular testing to exclude a partial mole. Even with the retrospective systematic morphologic review, only 23% (3/13) exhibited the combination of chorionic villous enlargement of ≥2.5 mm and cisterns, which has been previously established as the morphologic criteria with the highest predictive value for a molecularly defined partial mole. The other 77% exhibited focal, limited, variable degrees and extent of villous morphologic alterations. We conclude that, given the high prevalence of partial mole among products of conception with known fetal triploidy and the low prevalence of diagnostic morphologic findings in such specimens, reflex genotype testing should be performed in all such cases, regardless of whether or not the morphologic features are suspicious for a partial mole. This reflex testing strategy mitigates against the subjectivity of determining whether subtle villous abnormalities are significant enough to merit pursuing genotype testing. The success of this strategy depends on the clinician documenting the fetal triploidy result at the time of submitting the products of conception specimen and therefore clinician education is needed. Finally, it remains to be determined whether the risk for postmolar gestational trophoblastic disease is the same in diandric triploid gestations that exhibit classic morphologic features as in those that exhibit minimal or negligible villous morphologic abnormalities.

Preconception serum lipids and lipophilic micronutrient levels are associated with live birth rates after IVF.

RESEARCH QUESTION: Is a mixture of preconception serum lipids and lipophilic micronutrients associated with clinical pregnancy and live births? DESIGN: In this prospective cohort study, blood serum was collected on the day of oocyte retrieval for 180 women undergoing IVF at an academic reproductive health centre. Concentrations of lipids (phospholipids, total cholesterol, high- and low-density lipoproteins, and triglycerides) and lipophilic micronutrients (α-, δ-, and γ-tocopherols, retinol, ß- and α-carotenes, ß-cryptoxanthin, lutein and lycopene) were determined using diagnostic reagent kits and high-performance liquid chromatography. Poisson regression was used with robust variance estimation to evaluate changes in Z-scores for the mixture of serum lipid and lipophilic micronutrient concentrations as predictors of embryo implantation, clinical pregnancy and live birth, adjusted for age, body mass index (BMI), race, smoking status, infertility diagnosis, ovarian stimulation protocol and other measured lipid and lipophilic micronutrient concentrations. RESULTS: Each SD higher serum triglyceride concentration was associated with a lower chance of live birth (RR 0.54; 95% CI 0.33 to 0.90) whereas a 1 SD higher serum α-tocopherol concentration, as part of a mixture of serum lipids and lipophilic micronutrients, was associated with a higher likelihood for a live birth (RR 1.61; 95% CI 1.11 to 2.36). Serum ß-carotene concentrations were associated with live birth in a non-linear fashion; low ß-carotene was associated with a lower chance of live birth and high ß-carotene with a higher chance of live birth. CONCLUSION: Although components of a mixture of lipids and lipophilic micronutrients were associated with live birth outcomes after IVF, a larger investigation is necessary to fully evaluate the potential clinical implications.

Ultra-trace element analysis of human follicular fluid by ICP-MS/MS: pre-analytical challenges, contamination control, and matrix effects.

Follicular fluid (FF), which is the fluid that envelops the developing oocyte (egg cell) in the ovary, can be analyzed to assess trace element content as well as to determine potential exposure to toxic elements in women seeking in vitro fertilization (IVF) treatment. Such measurements may be useful in establishing associations with potential adverse effects on oocyte viability and subsequent pregnancy outcomes. The principal goal of this study was to leverage the next generation of inorganic mass spectrometry based on ICP-MS/MS to address the numerous analytical challenges of (ultra-)trace element analysis of human FF specimens. Ultra-trace element measurements are defined by the Clinical Laboratory Standards Institute as fluid concentrations below 10 µg L-1 or tissue mass fractions below 1 µg g-1. Stringent pre-analytical procedures were developed to minimize exogenous contamination during FF specimen collection and storage in a prospective study of 56 women seeking IVF treatment. ICP-MS/MS instrumental parameters were carefully optimized, and the method validated for 11 biologically important elements that included 4 at trace levels (Cu, Se, Sr, and Zn) and 7 at ultra-trace levels (As, Cd, Co, Mo, Mn, Hg, and Pb). Method limits of detection (LODs) for ultra-trace elements varied from 5.6 ng L-1 for Cd to 0.11 µg L-1 for Mo. A total of 197 human FF specimens were analyzed using the proposed ICP-MS/MS method with 84% of specimens detectable for Pb and 100% detectable for Co, Cu, Mn, Mo, Sr, and Zn. The method based on ICP-MS/MS was compared to a previous method developed for FF using SF-ICP-MS.

Interpregnancy interval and singleton pregnancy outcomes after frozen embryo transfer.

OBJECTIVE: To describe the relationship between interpregnancy interval (IPI) and perinatal outcomes in singleton live births after frozen embryo transfer (FET). DESIGN: Retrospective analysis of the Society for Assisted Reproductive Technology Clinical Outcome Reporting System cohort including patients with a history of live birth from ART who returned for an FET cycle between 2004 and 2013. SETTING: Not applicable. PATIENT(S): A total of 19,270 singleton live births from FET subsequent to a live birth. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Odds for preterm delivery (<37, <34, <28 weeks) and low birth weight (<2,500, <1,500 g) adjusted for age, body mass index, and history of prior preterm delivery. RESULT(S): Of 74,456 autologous FET cycles following an index live birth, 24,091 resulted in a repeat live birth, with 19,270 singleton live births. An IPI of <12 months occurred in 19% of cycles. Adjusted odds (aORs) for preterm delivery at <37 weeks were significantly increased for an IPI of <6 months (aOR 2.05, 95% confidence interval [CI] 1.48-2.84), 6 to <12 months (aOR 1.26, 95% CI 1.06-1.49), and 18 to <24 months (aOR 1.23, 95% CI 1.06-1.43) when compared with the reference interval of 12 to <18 months. Additionally, an IPI of <6 months was associated with increased odds for low birth weight (aOR 3.06, 95% CI 2.07-4.52) and very low birth weight (aOR 5.65, 95% CI 2.96-10.84) compared with an IPI of 12 to <18 months. CONCLUSION(S): In this nationally representative population, an interval from delivery to start of an FET cycle of <12 months is associated with increased odds for preterm delivery among singleton live births. Consistent with data for patients undergoing fresh IVF, the data support delaying FET 12 months from a live birth.

Decreased clinical pregnancy and live birth rates after short interval from delivery to subsequent assisted reproductive treatment cycle.

STUDY QUESTION: Does the interval from delivery to initiation of a subsequent ART treatment cycle impact clinical pregnancy or live birth rates? SUMMARY ANSWER: An interval from delivery to treatment start of <6 months or ≥24 months is associated with decreased likelihood of clinical pregnancy and live birth. WHAT IS KNOWN ALREADY: Short interpregnancy intervals are associated with poor obstetric outcomes in the naturally conceiving population prompting birth spacing recommendations of 18-24 months from international organizations. Deferring a subsequent pregnancy attempt means a woman will age in the interval with an attendant decline in her fertility. STUDY DESIGN, SIZE, DURATION: Retrospective analysis of the Society for Assisted Reproductive Technology Clinical Outcome Reporting System (SARTCORS) cohort containing 61 686 ART cycles from 2004 to 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS: The delivery-to-cycle interval (DCI) was calculated for patients from SARTCORS with a history of live birth from ART who returned to the same clinic for a first subsequent treatment cycle. Generalized linear models were fit to determine the risk of clinical pregnancy and live birth by DCI with subsequent adjustment for factors associated with outcomes of interest. Predicted probabilities of clinical pregnancy and live birth were generated from each model. MAIN RESULTS AND THE ROLE OF CHANCE: A DCI of <6 months was associated with a 5.6% reduction in probability of clinical pregnancy (40.1 ± 1.9 versus 45.7 ± 0.6%, P = 0.009) and 6.8% reduction in live birth (31.6 ± 1.7 versus 38.4 ± 0.6%, P = 0.001) per cycle start compared to a DCI of 12 to <18 months. A DCI of ≥24 months was associated with a 5.1% reduction in probability of clinical pregnancy (40.6 ± 0.5 versus 45.7 ± 0.6%, P < 0.001) and 5.7% reduction in live birth (32.7 ± 0.5 versus 38.4 ± 0.6%, P < 0.001) compared to 12 to <18 months. LIMITATIONS, REASONS FOR CAUTION: The SART database is reliant upon self-report of many variables of interest including live birth. It remains unclear whether poorer outcomes are a result of residual confounding from factors inherent to the population with a very short or long DCI or the interval itself. WIDER IMPLICATIONS OF THE FINDINGS: Birth spacing recommendations for naturally conceiving populations may not be generally applicable to patients with a history of infertility. Patients planning ART treatment should wait a minimum of 6 months, but not more than 24 months, from a live birth for optimization of clinical pregnancy and live birth rates. STUDY FUNDING/COMPETING INTEREST(S): National Center for Advancing Translational Sciences, National Institutes of Health, UCSF-CTSI Grant number UL1TR001872. The authors have no competing interests.

Interpregnancy Interval and Singleton Live Birth Outcomes From In Vitro Fertilization.

OBJECTIVE: To describe the relationship between a short interpregnancy interval and adverse pregnancy outcomes in the population undergoing assisted reproductive technology. METHODS: This is a retrospective analysis using data from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System. The cohort includes patients with a history of live birth from assisted reproductive technology who returned for a fresh, autologous in vitro fertilization (IVF) cycle from 2004 to 2013. Interpregnancy interval was defined as the interval from live birth to cycle start. Logistic regression models of preterm delivery (less than 37 weeks of gestation) and low birth weight (less than 2,500 g) on interpregnancy interval were fit with adjustment for age, body mass index, and history of preterm delivery. Predicted probabilities were generated from the logistic model. RESULTS: Of 51,997 fresh IVF cycles after an index live birth, 17,536 resulted in a repeat live birth with 11,271 singleton live births from autologous IVF. An interpregnancy interval of less than 18 months occurred in 40.9% of cycles. Compared with a reference interpregnancy interval of 12 to less than 18 months, the adjusted odds ratio for singleton preterm delivery was 1.66 (95% CI 1.05-2.65) for an interpregnancy interval less than 6 months and 1.34 (95% CI 1.06-1.69) for 6 to less than 12 months. An interpregnancy interval 6 to less than 12 months was associated with a 3.0% increase in preterm delivery (13.6±1.1% vs 10.6±0.7%, P=.030) and a 2.7% increase in low birth weight (8.0±0.9% vs 5.3±0.5%, P=.025) compared with an interpregnancy interval of 12 to less than 18 months. CONCLUSION: In this nationally representative population, an interval from delivery to treatment start of less than 12 months is associated with increased rates of preterm delivery and low birth weight in singleton live births from assisted reproductive technology. The data support delaying the start of IVF treatment 12 months from a live birth, but do not suggest a benefit from a longer interval as has been recommended for naturally conceiving couples.

A higher prevalence of endometriosis among Asian women does not contribute to poorer IVF outcomes.

PURPOSE: The purpose of the study was to determine whether diagnosis of endometriosis or endometriosis with endometrioma influences in vitro fertilization (IVF) outcomes in an ethnically diverse population. METHODS: Women undergoing a first IVF cycle (n = 717) between January 1, 2008 and December 31, 2009, at a university-affiliated infertility clinic, were retrospectively assessed for an endometriosis diagnosis. Differences in prevalence of endometriosis by ethnicity were determined, as well as differences in IVF success by ethnicity, with a focus on country of origin for Asian women. A multivariate model was generated to assess the relative contributions of country of origin and endometriosis to chance of clinical pregnancy with IVF. RESULTS: Endometriosis was diagnosed in 9.5% of participants; 3.5% also received a diagnosis of endometrioma. Endometriosis prevalence in Asian women was significantly greater than in Caucasians (15.7 vs. 5.8%, p < 0.01). Women of Filipino (p < 0.01), Indian (p < 0.01), Japanese (p < 0.01), and Korean (p < 0.05) origin specifically were more likely to have endometriosis than Caucasian women, although there was no difference in endometrioma presence by race/ethnicity. Oocyte quantity, embryo quality, and fertilization rates did not relate to endometriosis. Clinical pregnancy rates were significantly lower for Asian women, specifically in Indian (p < 0.05), Japanese (p < 0.05), and Korean (p < 0.05) women, compared to Caucasian women, even after controlling for endometriosis status. CONCLUSIONS: The prevalence of endometriosis appears to be higher in Filipino, Indian, Japanese, and Korean women presenting for IVF treatment than for Caucasian women; however, the discrepancy in IVF outcomes was conditionally independent of the presence of endometriosis. Future research should focus on improving pregnancy outcomes for Asian populations whether or not they are affected by endometriosis, specifically in the form of longitudinal studies where exposures can be captured prior to endometriosis diagnoses and infertility treatment.

Associations between PON1 enzyme activities in human ovarian follicular fluid and serum specimens.

The importance of high-density lipoprotein (HDL) particle components to reproduction is increasingly recognized, including the constituent paraoxonase 1 (PON1). However, the reliability characteristics of PON1 enzymes in ovarian follicular fluid (FF) as biomarkers for clinical and epidemiologic studies have not been described. Therefore, we characterized PON1 enzymes in FF and serum and assessed the impact of the PON1 Q192R polymorphism on associations between enzyme activities in two compartments. We also evaluated associations between HDL particle size and enzyme activities. We collected FF and serum from 171 women undergoing in vitro fertilization. PON1 activities were measured as paraoxonase and arylesterase activities, and HDL particle size was determined by 1H NMR spectrometry. Reliability indices for PON1 activities were characterized and we evaluated HDL particle sizes as predictors of PON1 enzyme activities. We found that PON1 enzyme activities were correlated between compartments, but higher in serum than in FF. For FF, the index of individuality (II) was low and the coefficient of variation (CV%) was high for paraoxonase activity overall (0.12 and 11.51%, respectively). However, IIs increased (0.33-1.30) and CV%s decreased (5.58%-8.52%) when stratified by PON1 Q192R phenotype. The intraclass correlation coefficient (ICC) for FF paraoxonase activity was high overall (0.89) but decreased when stratified by PON1 Q192R phenotype (0.43-0.75). We found similar, although more modest, patterns for FF arylesterase activity. For enzyme activities in serum, ICCs were close to 1.00 across all phenotypes. Additionally, different HDL particle sizes predicted PON1 enzyme activities according to PON1 Q192R phenotype. Overall, stratification by PON1 Q192R phenotype improved the reliability characteristics of FF PON1 enzymes as biomarkers for use in clinical investigations but diminished usefulness for epidemiologic studies. Thus, we recommend stratification by PON1 Q192R phenotype for clinical but not epidemiologic investigations, when employing FF PON1 enzyme activity biomarkers.

Persistent organic pollutants (POPs) in human follicular fluid and in vitro fertilization outcomes, a pilot study.

Persistent organic pollutants (POPs) are ubiquitously distributed among the U.S. population and adversely impact human reproduction. These compounds have been detected in human ovarian follicular fluid (FF), where they directly contact a developing oocyte. As a pilot investigation, we measured 43 polychlorinated biphenyl (PCB) congeners, p,p'-dichlorodiphenyltrichloroethane (DDT), and its persistent metabolite p,p'-dichlorodiphenyldichloroethylene (DDE) in residual FF collected from 32 women undergoing in vitro fertilization (IVF). We identified significant inverse associations between higher levels of PCB congeners and indicators of ovarian reserve (e.g., antral follicle count), follicular response to administered gonadotropins (e.g., peak estradiol, number of oocytes retrieved, endometrial thickness), intermediate IVF endpoints (e.g., oocyte fertilization and embryo quality), and clinical IVF outcomes (e.g., embryo implantation and live birth), after adjusting for body mass index, cigarette smoking, race, and age. Our results suggest that ongoing exposure to POPs impacts IVF and merit confirmation in a larger and more definitive future study.

Associations between IVF outcomes and essential trace elements measured in follicular fluid and urine: a pilot study.

PURPOSE: A hypothesis-generating pilot study exploring associations between essential trace elements measured in follicular fluid (FF) and urine and in vitro fertilization (IVF) endpoints. METHODS: We recruited 58 women undergoing IVF between 2007 and 2008, and measured cobalt, chromium, copper, manganese, molybdenum, and zinc in FF (n = 46) and urine (n = 45) by inductively coupled plasma mass spectrometry (ICP-MS). We used multivariable regression models to assess the impact of FF and urine trace elements on IVF outcomes, adjusted for age, body mass index, race, and cigarette smoking. RESULTS: Trace elements were mostly present at lower concentrations in FF than in urine. The average number of oocytes retrieved was positively associated with higher urine cobalt, chromium, copper, and molybdenum concentrations. FF chromium and manganese were negatively associated with the proportion of mature oocytes, yet urine manganese had a positive association. FF zinc was inversely associated with average oocyte fertilization. Urine trace elements were significant positive predictors for the total number of embryos generated. FF copper predicted lower embryo fragmentation while urine copper was associated with higher embryo cell number and urine manganese with higher embryo fragmentation. No associations were detected for implantation, pregnancy, or live birth. CONCLUSIONS: Our results suggest the importance of trace elements in both FF and urine for intermediate, although not necessarily clinical, IVF endpoints. The results differed using FF or urine biomarkers of exposure, which may have implications for the design of clinical and epidemiologic investigations. These initial findings will form the basis of a more definitive future study.

Bisphenol A and ovarian steroidogenesis.

Bisphenol A is widely used as a component in polycarbonate plastics for food and beverage packaging, epoxy linings for canned foods, and dental sealants, among other applications. Experimental literature demonstrates BPA's affinity for estrogen receptors and downstream effects on estrogen-responsive genes. Additional data suggest that BPA reduces endogenous estrogen synthesis, likely by antagonizing ovarian enzyme activities involved in sex-steroid hormone synthesis. More specifically, evidence indicates BPA-mediated disruption of STAR, CYP450scc, and HSD-3ß in theca cells and CYP450 aromatase activity in granulosa cells. Yet the results of the few human studies reported to date are equivocal. It also remains in question the extent to which BPA penetrates developing ovarian follicles. Uncertainty as to the relevance of experimental BPA doses and administration routes for common human exposure levels limits extrapolation of experimental results. To more definitively address the potential risk of BPA on human ovarian steroidogenesis, additional experimental studies using biologically active BPA doses likely to reflect those within the ovarian follicle will be necessary, as will additional prospective investigations in human populations with the use of standardized assay methodology.