The use of immunomodulation therapy in women with recurrent implantation failure undergoing assisted conception: A multicentre cohort study

PROBLEM

Recurrent implantation failure (RIF) after multiple embryo transfers remains a vexing problem and immunomodulators have been used with conflicting results. This study aims to assess the effect of immunomodulation therapy on live birth rate (LBR) in women with RIF undergoing assisted reproduction treatment (ART).

METHOD OF STUDY DESIGN

This is a retrospective cohort study in multicentre network of private assisted conception units in the UK. The study included women who had at least two failed attempts of embryo transfers at CARE fertility network in the period from 1997 to 2018. Women in the treatment group had immunomodulator drugs in the form of corticosteroids, low molecular weight heparin (LMWH), and intravenous intralipid (IVIL) infusions, either separately or in combination, after immunological testing, in addition to standard ART whilst women in the control group had only ART without immunomodulators. The primary outcome was LBR per cycle. Secondary outcomes included the rates of clinical pregnancy (CPR), cumulative live birth (CLBR), and miscarriage.

RESULTS

A total of 27 163 ART cycles fulfilled the inclusion criteria, of which 5083 had immunomodulation treatment in addition to standard ART treatment, and 22 080 had standard ART treatment alone. Women in the treatment group were significantly older (mean age 38.5 vs. 37.1 years, p < .001), and had a higher number of previous failed ART cycles (mean 4.3 vs. 3.8, p < .01). There was a higher LBR in women who received immunomodulation therapy when compared with the control group (20.9% vs. 15.8%, odds ratio [OR] 1.4, 95% confidence interval [CI] 1.29-1.53, p < .001). Multivariate regression analysis showed that immunomodulation treatment was a significant independent predictor of live birth after adjusting for other confounders (adjusted OR [aOR] 1.33, 95% CI 1.15-1.54, p < .001). Survival analysis showed a higher CLBR in the treatment group (adjusted hazard ratio [aHR] 1.78, 95% CI 1.62-1.94, p < .001).

CONCLUSION(S)

This study provides evidence of a potential beneficial effect of immunomodulation therapy in women with RIF after immunological testing. There remains a need for high quality, adequately powered multicentre RCTs to robustly address the role of immunomodulation in women with RIF. There is also an urgent need for standardised screening tests for immune disorders that could preclude implantation.

The effect of frozen embryo transfer regimen on the association between serum progesterone and live birth: a multicentre prospective cohort study (ProFET)

STUDY QUESTION

What is the association between serum progesterone levels on the day of frozen embryo transfer (FET) and the probability of live birth in women undergoing different FET regimens?

SUMMARY ANSWER

Overall, serum progesterone levels <7.8 ng/ml were associated with reduced odds of live birth, although the association between serum progesterone levels and the probability of live birth appeared to vary according to the route of progesterone administration.

WHAT IS KNOWN ALREADY

Progesterone is essential for pregnancy success. A recent systematic review showed that in FET cycles using vaginal progesterone for endometrial preparation, lower serum progesterone levels (<10 ng/ml) were associated with a reduction in live birth rates and higher chance of miscarriage. However, there was uncertainty about the association between serum progesterone levels and treatment outcomes in natural cycle FET (NC-FET) and HRT-FET using non-vaginal routes of progesterone administration.

STUDY DESIGN SIZE DURATION

This was a multicentre (n = 8) prospective cohort study conducted in the UK between January 2020 and February 2021.

PARTICIPANTS/MATERIALS SETTING METHODS

We included women having NC-FET or HRT-FET treatment with progesterone administration by any available route. Women underwent venepuncture on the day of embryo transfer. Participants and clinical personnel were blinded to the serum progesterone levels. We conducted unadjusted and multivariable logistic regression analyses to investigate the association between serum progesterone levels on the day of FET and treatment outcomes according to the type of cycle and route of exogenous progesterone administration. Our primary outcome was the live birth rate per participant.

MAIN RESULTS AND THE ROLE OF CHANCE

We studied a total of 402 women. The mean (SD) serum progesterone level was 14.9 (7.5) ng/ml. Overall, the mean adjusted probability of live birth increased non-linearly from 37.6% (95% CI 26.3-48.9%) to 45.5% (95% CI 32.1-58.9%) as serum progesterone rose between the 10th (7.8 ng/ml) and 90th (24.0 ng/ml) centiles. In comparison to participants whose serum progesterone level was ≥7.8 ng/ml, those with lower progesterone (<7.8 ng/ml, 10th centile) experienced fewer live births (28.2% versus 40.0%, adjusted odds ratio [aOR] 0.41, 95% CI 0.18-0.91, P = 0.028), lower odds of clinical pregnancy (30.8% versus 45.1%, aOR 0.36, 95% CI 0.16-0.79, P = 0.011) and a trend towards increased odds of miscarriage (42.1% versus 28.7%, aOR 2.58, 95% CI 0.88-7.62, P = 0.086). In women receiving vaginal progesterone, the mean adjusted probability of live birth increased as serum progesterone levels rose, whereas women having exclusively subcutaneous progesterone experienced a reduction in the mean probability of live birth as progesterone levels rose beyond 16.3 ng/ml. The combination of vaginal and subcutaneous routes appeared to exert little impact upon the mean probability of live birth in relation to serum progesterone levels.

LIMITATIONS REASONS FOR CAUTION

The final sample size was smaller than originally planned, although our study was adequately powered to confidently identify a difference in live birth between optimal and inadequate progesterone levels. Furthermore, our cohort did not include women receiving oral or rectal progestogens.

WIDER IMPLICATIONS OF THE FINDINGS

Our results corroborate existing evidence suggesting that lower serum progesterone levels hinder FET success. However, the relationship between serum progesterone and the probability of live birth appears to be non-linear in women receiving exclusively subcutaneous progesterone, suggesting that in this subgroup of women, high serum progesterone may also be detrimental to treatment success.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by CARE Fertility and a doctoral research fellowship (awarded to P.M.) by the Tommy's Charity and the University of Birmingham. M.J.P. is supported by the NIHR Birmingham Biomedical Research Centre. S.F. is a minor shareholder of CARE Fertility but has no financial or other interest with progesterone testing or manufacturing companies. P.L. reports personal fees from Pharmasure, outside the submitted work. G.P. reports personal fees from Besins Healthcare, outside the submitted work. M.W. reports personal fees from Ferring Pharmaceuticals, outside the submitted work. The remaining authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT04170517.

O-009 Controlled ovarian stimulation (COS) protocols for assisted reproduction: a Cochrane systematic review and network meta-analysis

Study question

What is the relative effectiveness and safety of existing COS protocols for women undergoing assisted reproductive technology (ART) treatment?

Summary answer

There was no difference in live birth between all protocols, but short antagonist protocols may reduce ovarian hyperstimulation syndrome in women with predicted normal/high response.

What is known already

Controlled ovarian stimulation is an essential step in most ART cycles. It involves the administration of exogenous gonadotrophins to induce multifollicular growth, usually in addition to drugs that prevent untimely ovulation by suppressing the pituitary gland. Different treatment combinations may be used in COS. These vary according to the type of drugs administered for pituitary suppression (e.g., gonadotrophin-releasing hormone [GnRH] agonists, antagonists) and ovarian stimulation (e.g., urinary or recombinant gonadotrophins). Drug dosages, timing and routes of administration also vary between different regimens. However, there is no consensus on how the existing COS protocols rank according to their effectiveness and safety.

Study design, size, duration

We searched the following databases to November 2021: MEDLINE, EMBASE, CINAHL, CENTRAL and ClinicalTrials.gov. We included randomised controlled trials (RCTs) comparing at least two COS protocols using GnRH agonists or antagonists for pituitary suppression; and human menopausal gonadotrophin (hMG), urinary or recombinant follicle-stimulating hormone (u/rFSH), with or without luteinising hormone (LH) for ovarian stimulation. The primary outcomes were the rates of live birth (LBR) and ovarian hyperstimulation syndrome (OHSS) per participant after one stimulation cycle.

Participants/materials, setting, methods

Two reviewers independently selected studies and extracted data. We conducted pairwise and network meta-analyses (NMA) according to participants’ predicted response to COS (normal, high and low). Using the Cochrane-RoB-1 tool, we restricted our primary analyses to RCTs at low risk of selection and other biases. We presented effect estimates as risk ratio (RR) with 95% confidence interval (CI) and considered I2&gt;50% as representing substantial heterogeneity. For each outcome, we generated ranking plots comparing different interventions.

Main results and the role of chance

In total, our searches identified 9464 studies. The primary analysis included 68 RCTs assessing 17861 women and 34 different COS protocols. The evidence showed that in women with predicted normal or high response, the use of short GnRH antagonist protocols may result in little to no difference in LBR (RR 0.98, 95% CI 0.85 to 1.13; 6 studies; 2063 women; I2 = 0%; low-certainty evidence) and a reduction in OHSS (RR 0.88, 95% CI 0.78 to 0.99; 7 studies; 2246 women; I2 = 0%; low-certainty evidence) compared with long GnRH agonist protocols. The rankogram comparing different COS protocols showed a probability of 98% that short GnRH antagonist regimens are the best treatment to prevent OHSS. Sensitivity analyses including all studies showed that in women with predicted normal response undergoing long GnRH agonist cycles for pituitary suppression, the use of rFSH for ovarian stimulation may result in decreased fresh-cycle LBR compared to hMG (RR 0.80, 95% CI 0.68 to 0.95; 7 studies; 1575 women; I2 = 1%; low-certainty evidence). For the remaining interventions (e.g., agonist flare or progestogens for pituitary suppression, in combination with various gonadotrophin regimens) the evidence was uncertain of an effect or insufficient for quantitative synthesis.

Limitations, reasons for caution

The high number of interventions resulted in disconnected networks, limiting our ability to perform NMA for some comparisons. The certainty of the evidence was limited by serious risk of bias. Finally, the lack of data on cumulative LBR and differences in oocyte yield made comparisons between FSH preparations potentially unbalanced.

Wider implications of the findings

Our findings suggest that the use of short GnRH antagonist protocols may result in reduced OHSS rates in women with predicted normal or high ovarian response without compromising live birth rates. There is a paucity of high-quality RCTs comparing different gonadotrophin preparations (e.g., hMG versus rFSH) for COS.

Trial registration number

N/A

Chitosan-CdS Quantum Dots Biohybrid for Highly Selective Interaction with Copper(II) Ions

Cadmium sulfide (CdS) quantum dots (QDs) were homogeneously embedded into chitosan (CTS), denoted as CdS@CTS, via an in situ hydrothermal method. The intact structure of the synthesized materials was preserved using freeze-drying. The materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy, transmission electron microscopy, high-resolution TEM, scanning TEM, dispersive energy X-ray (EDX) for elemental analysis and mapping, Fourier transform infrared spectroscopy, nitrogen adsorption-desorption isotherms, thermogravimetric analysis, UV-vis spectroscopy, and diffuse reflectance spectroscopy (DRS). The synthesis procedure offered CdS QDs of 1-7 nm (average particle size of 3.2 nm). The functional groups of CTS modulate the in situ growth of CdS QDs and prevent the agglomeration of CdS QDs, offering homogenous distribution inside CTS. CdS@CTS QDs can also be used for naked-eye detection of heavy metals with high selectivity toward copper (Cu²⁺) ions. The mechanism of interactions between Cu²⁺ ions and CdS@CTS QDs were further studied.

Legacy halogenated organic contaminants in urban-influenced waters using passive polyethylene samplers: Emerging evidence of anthropogenic land-use-based sources and ecological risks

Legacy halogenated organic pollutants, including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), remain ubiquitous in the environment and continue to pose potential (eco-)toxicological threats because of their ongoing releases from land-based sources. This study investigated the spatial trends of freely dissolved PCBs and OCPs by polyethylene passive samplers, and provided evidence of their land-use-based sources and ecological risk in an urbanized estuary area of Narragansett Bay. Dissolved Σ₂₉PCB concentrations ranged from 0.01 to 1.37 ng L^-1, and exhibited higher concentrations in the upper, more urban/built-up watershed, and in north coastal areas. Major inputs of PCBs were urban stormwater or treated wastewater that might carry past releases of Aroclors, pigment manufacturing byproducts, and volatilization-associated PCBs from ageing buildings from the Narragansett watershed to the bay. The dioxin toxicity equivalent values of Σ₅PCBs were 8.6E-03 pg L^-1 in water. Dissolved OCP concentrations had similar spatial trends to PCBs and were dominated by DDTs (average 230 pg L^-1), followed by chlordanes (average 230 pg L^-1), and HCB (average 22 pg L^-1). Secondary sources of past usage and historic contamination were expected to re-enter the surface water via atmospheric transport and deposition. The risk quotients of DDE, DDD, DDT and α-Endosulfane showed medium to high ecological risks in the northern area, while chlordane, HCB, oxychlordane, and heptachlor epoxide showed low to negligible risks in all zones. This study presented new insights into the presence, sources and transport of legacy halogenated organic contaminants in an urban estuary's watershed by combining passive samplers and geographic information system (GIS) technology. The approach is promising and could be extended to get better understand of terrestrial pollutant mobilization into estuaries affected by anthropogenic activities.

Net volatilization of PAHs from the North Pacific to the Arctic Ocean observed by passive sampling

The North Pacific-Arctic Oceans are important compartments for semi-volatile organic compounds' (SVOCs) global marine inventory, but whether they act as a "source" or "sink" remains controversial. To study the air-sea exchange and fate of SVOCs during their poleward long-range transport, low-altitude atmosphere and surface seawater were measured for polycyclic aromatic hydrocarbons (PAHs) by passive sampling from July to September in 2014. Gaseous PAH concentrations (0.67-13 ng m^-3) were dominated by phenanthrene (Phe) and fluorene (Flu), which displayed an inverse correlation with latitude, as well as a significant linear relationship with partial pressure and inverse temperature. Concentrations of PAHs in seawater (1.8-16 ng L^-1) showed regional characteristics, with higher levels near the East Asia and lower values in the Bering Strait. The potential impact from the East Asian monsoon was suggested for gaseous PAHs, which - similar to PAHs in surface seawater - were derived from combustion sources. In addition, the data implied net volatilization of PAHs from seawater into the air along the entire cruise; fluxes displayed a similar pattern to regional and monthly distribution of PAHs in seawater. Our results further emphasized that air-sea exchange is an important process for PAHs in the open marine environments.

The value of serum progesterone level on day of human chorionic gonadotrophin administration / metaphase II oocyte ratio in predicting IVF/ICSI outcome in patients with normal ovarian reserve

Background

The clinical implication of the increased serum progesterone level on the day of HCG administration in assisted reproduction treatment (ART) is still controversial. The current study aimed to compare the predictive value of serum progesterone on day of HCG administration / metaphase II oocyte (P/MII) ratio on IVF/ ICSI outcome to serum progesterone (P) level alone and the ratio of serum progesterone/estradiol level (P/E2) ratio in prediction of pregnancy rates after ART.

Material & methods

Two hundred patients admitted to the IVF/ICSI program at Minia IVF center in Egypt in the period from October 2016 to May 2018 were included in this study. Serum Progesterone (P) and Estradiol (E2) levels were estimated on the day of HCG administration. The ratio between serum P and the number of MII oocytes (P/MII ratio) was calculated and the predictive values of the three parameters (P, P/E2 ratio and P/MII ratio) in prediction of cycle outcomes were measured.

Results

P/ MII oocyte ratio was significantly lower in patients who attained clinical pregnancy (n = 97) as compared with those who couldn’t whilst there was no significant difference in P and P/E2 ratio between the two groups. Using a cut off value of 0.125, the sensitivity and specificity of progesterone/ MII ratio in prediction of no pregnancy in IVF/ICSI were 75.7 and 77.1% respectively with the area under The Receiver operating curve (ROC-AUC) = 0.808. The respective values of the ROC-AUC for the P and P/E2 ratio were 0.651 and 0.712 with sensitivity and specificity of 71.2 and 73.5%for P level and of 72.5 and 75.3% for P/E2 ratio. Implantation or clinical pregnancy rates were significantly different between patients with high and low P/MII ratio irrespective of day of embryo transfer (day 3 or 5).

Conclusions

In patients with normal ovarian response, serum progesterone on day of HCG / MII oocyte ratio can be a useful predictor of pregnancy outcomes and in deciding on freezing of all embryos for later transfer instead of high progesterone level alone.

Role of suppression of endometriosis with progestins before IVF-ET: a non-inferiority randomized controlled trial

BACKGROUND

Endometriosis affects the responsiveness to ovarian stimulation. This study aimed to assess the role of Dienogest pretreatment for endometriosis suppression as compared to Gonadotropin-releasing hormone agonist (GnRHa) in patients with endometriosis pursuing IVF treatment.

METHODS

In this randomized controlled trial, 134 women with endometriosis-related infertility were randomly allocated to group A (n = 67) who had monthly depot GnRHa for 3 months before ovarian stimulation in IVF treatment (Ultra-long protocol), and Group B (n = 67) who had daily oral Dienogest 2 mg/d for 3 months before starting standard long protocol for IVF. The primary outcome measure was the number of oocytes retrieved. The secondary outcome measures included the number of mature oocytes, fertilization rate, quality of life assessed by FertiQoL scores, cost of treatment, and pregnancy outcomes.

RESULTS

Although there was no statistically significant difference between both groups regarding ovarian stimulation, response parameters, and pregnancy outcomes, the Dienogest group had a lower cost of treatment (2773 vs. 3664 EGP, P < 0.001), lower side effects (29.9% vs. 59.7%, P < 0.001), higher FertiQoL treatment scores (33.2 vs. 25.1, P < 0.001) and higher tolerability scores (14.1 vs. 9.4, P < 0.001 < 0.001).

CONCLUSION

Our study indicates that Dienogest is a suitable and safe substitute for GnRHa pretreatment in endometriosis patients.

TRIAL REGISTRATION

NCT04500743 "Retrospectively registered on August 5, 2020".

Role of first-trimester three-dimensional (3D) power Doppler of placental blood flow and 3D placental volume in early prediction of pre-eclampsia

OBJECTIVE

To assess the efficacy of first-trimester three-dimensional (3D) placental volume as well as 3D power Doppler of placental vascular indices for early prediction of pre-eclampsia.

METHODS

The prospective cohort study included over 2019 women with a singleton pregnancy in their first trimester at 11-13+ weeks of pregnancy. All women were examined by 3D abdominal ultrasound, including Doppler techniques for the placental volume and placental vascular indices. Uterine artery Doppler indices were also assessed. All participants were cared for until delivery for assessment of pregnancy outcomes.

RESULTS

In all, 163 women developed pre-eclampsia while 1856 women remained normotensive. The women with pre-eclampsia had significantly lower placental volume (77.09 ml vs. 99.8 ml, p < 0.001), and placental vascular indices (vascularization index, flow index, and vascularization flow index were 7.41 vs. 9.89, 39.03 vs. 46.63, and 2.77 vs. 4.4, respectively, p < 0.001). In contrast, women with pre-eclampsia had significantly high mean uterine pulsatility index and resistance index (2.02 vs. 1.11, 0.83 vs. 0.64, respectively, p < 0.001) compared with the normotensive women. The placental vascular indices were highly sensitive, whereas the placental volume and the mean uterine pulsatility index and resistance index had higher specificity for the prediction of pre-eclampsia.

CONCLUSION

First-trimester assessment through 3D placental volume and power Doppler of placental vascular indices, especially in combination with uterine artery Doppler assessment, revealed an increase in the accuracy of early detection of women at risk for developing pre-eclampsia.

Clinical utility of transient elastography as an imaging tool to assess the short-term impact of laparoscopic sleeve gastrectomy, together with clinical and biochemical parameters and clinico-biochemical indices, on obese patients with nonalcoholic fatty liver disease: An Egyptian pilot study

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a metabolic liver disorder commonly attributed to fatty acid deposition that can induce hepatic necroinflammation, defined as nonalcoholic steatohepatitis (NASH). It is strongly associated with obesity. Laparoscopic sleeve gastrectomy (LSG) is a favorable surgical modality for the treatment of morbid obesity.

AIM

Our study evaluated the impact of LSG on patients with NAFLD and morbid obesity, 3 months after the operation, through clinical and biochemical characteristics, clinico-biochemical indices, and imaging parameters.

PATIENTS AND METHODS

Morbidly obese patients with NAFLD±NASH underwent LSG. They were thoroughly evaluated clinically (body weight, body mass index, waist circumference) and biochemically (transaminases and triglycerides), as well as through the fatty liver index (FLI), the hepatic steatosis index (HSI), and ultrasound elastography imaging studies (liver stiffness measurement [LSM] and the controlled attenuation parameter [CAP]), before and 3 months after the LSG.

RESULTS

Twenty-six obese patients with NAFLD underwent LSG that resulted in a significantly high reduction in all the parameters analyzed, except for liver transaminases.

CONCLUSION

LSG is considered an efficient surgical modality for the treatment of morbidly obese patients with NAFLD.

Management of bleeding from morbidly adherent placenta during elective repeat caesarean section: retrospective -record -based study

Background

Controlling massive haemorrhage from morbidly adherent placenta (MAP) at caesarean section is a major surgical challenge to obstetricians. This study compares different intra-operative interventions to control haemorrhage from morbidly adherent placenta and its impact on maternal morbidity.

Methods

Retrospective analysis was done for baseline characteristics, intra-operative and postoperative complications of 125 patients with morbidly adherent placenta who had elective CS at 35–38 weeks gestation in the period from 01/2012 to 01/2017. The included patients were categorized into three groups according to intra-operative interventions they had for controlling bleeding; Group A (n = 42) had only balloon tamponade, Group B (n = 40) had balloon tamponade and bilateral uterine artery ligation, in Group C (n = 43) all cases were managed by bilateral uterine artery ligation and inverting the cervix into the uterine cavity and suturing the anterior and/or the posterior cervical lips into the anterior and/or posterior walls of the lower uterine segment using the cervix as a natural tamponade.

Results

There were no differences of baseline characteristics of patients in all groups. Group C had significantly better outcomes as compared with groups A and B; less total blood loss (Group C 2869.5 ml vs Group B 4580 ml, Group A 4812 ml, P <  0.001), less requirement of blood transfusion more than 4 units (Group C 4/43, Group B 10/40,Group A 12/42, P <  0.02), significant reduction in prolonged hospital stay over 10 days (Group C 2/43, Group B 9/40,Group A 14/42, P < 0.001) and lower risk of coagulopathy (Group C 4/43, B 8/40, A 9/42), visceral injuries (Group C 4/43 vs B 8/40, A 10/42,P < 0.01) and need for hysterectomy (Group C 4/43 vs B 11/40, A 13/42,P < 0.001).

Conclusion

A combination bilateral uterine artery ligation and using the cervix as a natural tamponade are very effective and simple methods in controlling bleeding resulting from separated placenta accreta.

Trial registration

The findings are part of the research project registered in ClinicalTrials.gov NCT02590484. Registered 28 October 2015.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2244-4) contains supplementary material, which is available to authorized users.

Dispersed Ag2O/Ag on CNT-Graphene Composite: An Implication for Magnificent Photoreduction and Energy Storage Applications

A simple hydrothermal route assisted by a triblock copolymer was used to synthesize Ag2O/Ag nanoparticles on a robotic support consists of functionalized MWCNTs and graphene composite (Ag2O/Ag/CNT-graphene). The composites together with the individual analog of Ag/CNT and Ag/graphene were characterized by means of XRD, TEM-SAED, N2 sorptiometry, Raman, FTIR, UV-Vis, and photoluminescence spectroscopy. These nanomaterials were then tested for the catalytic reduction of 4-nitrophenol (4-NP) to the technologically beneficial 4-aminophenol (4-AP). The Ag2O@Ag@CNT-graphene composite calcined at 400°C has shown fascinating reduction performances for 4-NP either in the dark (k = 0.014 s-1) or under visible light illumination (k = 0.039 s-1) in the presence of 5 mM NaBH4 compared to Ag/CNT (0.0112 s-1) and Ag/graphene (0.010 s-1) catalysts. This was chiefly because Ag2O@Ag@CNT-graphene comprises the highest pore volume (0.49 cm3/g) and involves three types of pores in the margin from 1.8 to 4.0 nm in front of only one modal type of pores for the rest of the catalysts and thus maximizes the adsorptive capacity of the reactants (4-NP and NaBH4). Moreover, the former composite exhibits the highest concentration of the Ag2O component as established by numerous techniques in addition to the cyclic voltammetry, proposing it's facile reaction with 4-NP along with the simultaneous transfer of surface hydrogen and electrons from NaBH4 ions to produce 4-AP. The promotion of the p-n junction evaluated using the Mott-schottky equation on Ag2O@Ag@CNT-graphene assisted by charges separation and surface plasmon resonance bands of Ag and Ag2O are found to be advantageous for 4-NP reduction. The latter composite delivers a specific capacitance of 355 F g-1 at 1.0 A g-1 exceeding those of Ag/CNT (230 F g-1) and Ag/graphene (185 F g-1). The EIS study establishes the high electronic conductivity of the metallic Ag and Ag2O moieties, low internal resistance of CNT-graphene as well as the marked ionic transfer facilitated by the composite porous nature.

Land-use-based sources and trends of dissolved PBDEs and PAHs in an urbanized watershed using passive polyethylene samplers

Narragansett Bay is a temperate estuary on the Atlantic coast of Rhode Island in the north-eastern United States, which receives organic pollutants from urban and industrial activities in its watershed, though detailed knowledge on sources and fluxes is missing. Twenty-four polyethylene passive samplers were deployed in the surface water of the watershed around Narragansett Bay during June-July of 2014, to examine the spatial variability and possible sources of priority pollutants, namely dissolved polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). Dissolved ∑₂₂PAH concentrations ranged from 3.6 to 340 ng L^-1, and from 2.9 to 220 pg L^-1 for ∑₁₂PBDE. The spatial variability of the concentrations was correlated to land use pattern and population distribution, in particular with human activities within 2 km of sampling sites. River discharges derived from the concentrations of PAHs and PBDEs measured here were 10-20 times greater than their previously measured concentrations in the open waters of Narragansett Bay. These results imply that river waters are the main source of PAHs and PDBEs to the Bay and that major sink terms (e.g., sedimentation, degradation) affect their concentrations in the estuary. Predicted PAH and PBDE toxicity based on dissolved concentrations did not exceed 1 toxic unit, suggested that no toxicity occurred at the sampling sites.

Time Trends of Polybrominated Diphenyl Ethers (PBDEs) in Antarctic Biota

Polybrominated diphenyl ethers (PBDEs) are "emerged" contaminants that were produced and used as flame retardants in numerous consumer and industrial applications for decades until banned. They remain ubiquitously present in the environment today. Here, a unique set of >200 biotic samples from the Antarctic was analyzed for PBDEs, including phytoplankton, krill, fish, and fur seal milk, spanning several sampling seasons over 14 years. PBDE-47 and -99 were the dominant congeners determined in all samples, constituting >60% of total PBDEs. A temporal trend was observed for ∑₇PBDE concentrations in fur seal milk, where concentrations significantly increased (R² = 0.57, p < 0.05) over time (2000-2014). Results for krill and phytoplankton also suggested increasing PBDE concentrations over time. Trends of PBDEs in fur seal milk of individual seals sampled 1 or more years apart showed no clear temporal trends. Overall, there was no indication of PBDEs decreasing in Antarctic biota yet, whereas numerous studies have reported decreasing trends in the northern hemisphere. Similar PBDE concentrations in perinatal versus nonperinatal milk implied the importance of local PBDE sources for bioaccumulation. These results indicate the need for continued assessment of contaminant trends, such as PBDEs, and their replacements, in Antarctica.

Advancing the Use of Passive Sampling in Risk Assessment and Management of Sediments Contaminated with Hydrophobic Organic Chemicals: Results of an International Ex Situ Passive Sampling Interlaboratory Comparison

This work presents the results of an international interlaboratory comparison on ex situ passive sampling in sediments. The main objectives were to map the state of the science in passively sampling sediments, identify sources of variability, provide recommendations and practical guidance for standardized passive sampling, and advance the use of passive sampling in regulatory decision making by increasing confidence in the use of the technique. The study was performed by a consortium of 11 laboratories and included experiments with 14 passive sampling formats on 3 sediments for 25 target chemicals (PAHs and PCBs). The resulting overall interlaboratory variability was large (a factor of ∼10), but standardization of methods halved this variability. The remaining variability was primarily due to factors not related to passive sampling itself, i.e., sediment heterogeneity and analytical chemistry. Excluding the latter source of variability, by performing all analyses in one laboratory, showed that passive sampling results can have a high precision and a very low intermethod variability (<factor of 1.7). It is concluded that passive sampling, irrespective of the specific method used, is fit for implementation in risk assessment and management of contaminated sediments, provided that method setup and performance, as well as chemical analyses are quality-controlled.

Two week waits: What are we waiting for?

OBJECTIVES

To evaluate the two-week referral system by analysing the 2-week wait (2WW) referrals to the rapid access gynaecology clinic over one year. We have also sought to identify the risk factors for endometrial cancer to help setting criteria that can be used to prioritise urgent appointments, refine subsequent management strategies.

STUDY DESIGN

Retrospective review of the data of all women referred for suspected gynaecological cancers over one year via the 2 WW office at Queen's Hospital, Romford, UK. Data of all other women in whom a diagnosis of a gynaecological malignancy was made during the same period following non-urgent (non-2WW) referrals were also collected.

RESULTS

Over one year, a total of 1105 women were referred under the 2WW for suspected gynaecological malignancy. A total of 765 patients (69.23%) were referred with suspected endometrial cancer and the main indication for referral was postmenopausal bleeding. Hundred-seventy nine women (16.20%) were referred with suspected ovarian cancer. A pelvic mass found in 62 of these women and this was the main indication of referral. The number of women referred with suspected cervical cancer was 117 (10.59%) and the main indication for referral was postcoital bleeding. Forty-four women (3.98%) referred with suspected vulvo-vaginal cancer and the main presentation was vulval lesion. The positive predictive value of referrals for diagnosing endometrial, ovarian, cervical and vulvo-vaginal malignancy was 8.1%, 9.5%, 5.98% and 13.64% and the overall predictive value for diagnosing gynaecological malignancy was 8.33%. The predictive values of the 2WW referrals for diagnosing different types of gynaecological cancers in premenopausal women are low compared to postmenopausal women (1.86% and 9.89% respectively, p<0.001). The number of cancers diagnosed through non-urgent system was higher than the number diagnosed through urgent system (95 vs. 92). Presence of diabetes mellitus, increased endometrial thickness, prolonged bleeding and advancing age represent the best model for predicting endometrial cancer.

CONCLUSION

The overall predictive value of the 2WW system for suspected gynaecological malignancies is low particularly in premenopausal women. The current referral criteria need to be modified with a view to incorporating risk factors to prioritise urgent appointments and refine subsequent management plans.

National treatment programme of hepatitis C in Egypt: Hepatitis C virus model of care

Hepatitis C virus (HCV) infection is a major health problem in Egypt as the nation bears the highest prevalence rate worldwide. This necessitated establishing a novel model of care (MOC) to contain the epidemic, deliver patient care and ensure global treatment access. In this review, we describe the process of development of the Egyptian model and future strategies for sustainability. Although the magnitude of the HCV problem was known for many years, the HCV MOC only came into being in 2006 with the establishment of the National Committee for Control of Viral Hepatitis (NCCVH) to set up and implement a national control strategy for the disease and other causes of viral hepatitis. The strategy outlines best practices for patient care delivery by applying a set of service principles through identified clinical streams and patient flow continuums. The Egyptian national viral hepatitis treatment programme is considered one of the most successful and effective public health programmes. To date, more than one million patients were evaluated and more than 850 000 received treatment under the umbrella of the programme since 2006. The NCCVH has been successful in establishing a strong infrastructure for controlling viral hepatitis in Egypt. It established a nationwide network of digitally connected viral hepatitis-specialized treatment centres covering the country map to enhance treatment access. Practice guidelines suiting local circumstances were issued and regularly updated and are applied in all affiliated centres. This review illustrates the model and the successful Egyptian experience. It sets an exemplar for states, organizations and policy-makers setting up programmes for care and management of people with hepatitis C.

Estimation of Uncertainty in Air-Water Exchange Flux and Gross Volatilization Loss of PCBs: A Case Study Based on Passive Sampling in the Lower Great Lakes

Compared with dry and wet deposition fluxes, air-water exchange flux cannot be directly measured experimentally. Its model-based calculation contains considerable uncertainty because of the uncertainties in input parameters. To capture the inherent variability of air-water exchange flux of PCBs across the lower Great Lakes and to calculate their annual gross volatilization loss, 57 pairs of air and water samples from 19 sites across Lakes Erie and Ontario were collected using passive sampling technology during 2011-2012. Error propagation analysis and Monte Carlo simulation were applied to estimate uncertainty in the air-water exchange fluxes. Results from both methods were similar, but error propagation analysis estimated a smaller uncertainty than Monte Carlo simulation in cases of net deposition. Maximum likelihood estimations (MLE) of wind speed and air temperature were recommended to quantify the site-specific air-water exchange flux. An assumed 30-40% of relative uncertainty in overall air-water mass transfer velocity was confirmed. MLEs of volatilization fluxes of total PCBs across Lakes Erie and Ontario were 0.78 and 0.53 ng m^-2 day^-1, respectively, and gross volatilization losses of total PCBs over the whole lakes were 74 kg year^-1 for Lake Erie and 63 kg year^-1 for Lake Ontario. Mass balance analysis across Lake Ontario indicated that volatilization was the uppermost loss process of aqueous PCBs.

Gaseous and Freely-Dissolved PCBs in the Lower Great Lakes Based on Passive Sampling: Spatial Trends and Air-Water Exchange

Polyethylene passive sampling was performed to quantify gaseous and freely dissolved polychlorinated biphenyls (PCBs) in the air and water of Lakes Erie and Ontario during 2011-2012. In view of differing physical characteristics and the impacts of historical contamination by PCBs within these lakes, spatial variation of PCB concentrations and air-water exchange across these lakes may be expected. Both lakes displayed statistically similar aqueous and atmospheric PCB concentrations. Total aqueous concentrations of 29 PCBs ranged from 1.5 pg L(-1) in the open lake of Lake Erie (site E02) in 2011 spring to 105 pg L(-1) in Niagara (site On05) in 2012 summer, while total atmospheric concentrations were 7.7-634 pg m(-3) across both lakes. A west-to-east gradient was observed for aqueous PCBs in Lake Erie. River discharge and localized influences (e.g., sediment resuspension and regional alongshore transport) likely dominated spatial trends of aqueous PCBs in both lakes. Air-water exchange fluxes of Σ7PCBs ranged from -2.4 (±1.9) ng m(-2) day(-1) (deposition) in Sheffield (site E03) to 9.0 (±3.1) ng m(-2) day(-1) (volatilization) in Niagara (site On05). Net volatilization of PCBs was the primary trend across most sites and periods. Almost half of variation in air-water exchange fluxes was attributed to the difference in aqueous concentrations of PCBs. Uncertainty analysis in fugacity ratios and mass fluxes in air-water exchange of PCBs indicated that PCBs have reached or approached equilibrium only at the eastern Lake Erie and along the Canadian shore of Lake Ontario sites, where air-water exchange fluxes dominated atmospheric concentrations.

Changing sources of polychlorinated dibenzo-p-dioxins and furans in sediments and ecological risk for nekton in the lower Passaic River and Newark Bay, New Jersey, USA

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were measured in sediments (surface and deeper sediments) and porewater of the lower Passaic River and Newark Bay (New Jersey, USA) to apportion their sources and conduct an ecological risk assessment. Positive matrix factorization was applied to identify sources of PCDD/Fs. Five source profiles were extracted from the positive matrix factorization model applied to the sediment samples including chloranil, combustion, polychlorinated biphenyl impurities, mixed urban sources, and the historical contamination from the former Diamond Alkali plant. The ecological risk assessment was estimated using several lines of evidence depending on site-specific data (blue crab and fish samples representing different feeding habits and positions in the trophic wood web of the river). Porewater concentrations gave the best estimates of lipid concentrations especially in the blue crab samples (with an average factor difference of 3.8). Calculated hazard quotients (HQs) for the fish samples and blue crab were >1 based on the no-effect concentration and tissue screening concentration approaches. At the same time, calculated porewater toxic units were >1. Sediment concentrations exceeded the published sediment quality guidelines for the protection of fish and benthic species, indicating the existence of significant risk to the aquatic life in the Passaic River. Accordingly, further actions and control measures are needed to reduce the emission of PCDD/Fs from ongoing sources.

Transmyometrial versus very difficult transcervical embryo transfer: efficacy and safety

A difficult and traumatic embryo transfer can negatively impact on embryo implantation. This study retrospectively compared the outcomes of "very difficult transcervical embryo transfer" (vdTCET) versus transmyometrial embryo transfer (TMET) in a single centre over 10 years, reporting on 128 patients with vdTCET and 46 patients with TMET. The definition of vdTCET was a procedure rated by an experienced practitioner (with more than 100 transfers per year for >2 years) as very difficult and required two or more of the following: use of tenaculum, change of embryo transfer catheter and use of a stylet, reloading of the embryos or cancelling the procedure and freezing the embryo to transfer after cervical dilatation. The clinical pregnancy rates for TMET and vdTCET were 32.6% and 25%, respectively and the live birth rates were 26.1% and 16.4%, respectively. There was only one case of minor bleeding in the TMET group (2.2%). This study showed that TMET is a good alternative option in cases of vdTCET where it is impossible to achieve transcervical embryo transfer and may benefit cases with repeated failed cycles after vdTCET. Its superiority over vdTCET however could not be demonstrated.

Use of passive samplers to detect organochlorine pesticides in air and water at wetland mountain region sites (S-SE Brazil)

Low-density polyethylene (LDPE) passive samplers were deployed in upland surface waters and the overlying atmosphere during May and June 2012, to determine the transport and trends of freely dissolved and gaseous organochlorine pesticides (OCPs) along altitudinal gradients in mountain regions in south and southeast Brazil. Gaseous OCP concentrations were dominated by hexachlorobenzene (3.0-29 pg m(-3)) and endosulfans (Ʃ = α-endosulfan + β-endosulfan + endosulfan sulphate, 170-260 pg m(-3)), whereas freely dissolved endosulfans were significantly higher than all other OCPs (p < 0.001). The presence of some target pesticides at the highest elevation sites indicated their efficient high-altitude transport from regional sources. Air-water exchange gradients indicated net deposition of most volatile and recently banned OCPs (e.g., HCB, endosulfan) over Brazilian mountains. Moreover, the exposure of these sites to large-scale continental airflows with varying source contributions may partly explain the atmospheric deposition of selected OCPs over upland freshwaters at tropical and subtropical mountains sites in Brazil. These findings, coupled with LDPE passive air and water sampling measurements, point out the potential inputs from distant sources of semi-volatile chemicals to the two high-altitude sites.

Spatial Distribution, Air-Water Fugacity Ratios and Source Apportionment of Polychlorinated Biphenyls in the Lower Great Lakes Basin

Polychlorinated biphenyls (PCBs) continue to be contaminants of concern across the Great Lakes. It is unclear whether current concentrations are driven by ongoing primary emissions from their original uses, or whether ambient PCBs are dominated by their environmental cycling. Freely dissolved PCBs in air and water were measured using polyethylene passive samplers across Lakes Erie and Ontario during summer and fall, 2011, to investigate their spatial distribution, determine and apportion their sources and to asses their air-water exchange gradients. Average gaseous and freely dissolved ∑29 PCB concentrations ranged from 5.0 to 160 pg/m(3) and 2.0 to 55 pg/L respectively. Gaseous concentrations were significantly correlated (R(2) = 0.80) with the urban area within a 3-20 km radius. Fugacity ratios indicated that the majority of PCBs are volatilizing from the water thus acting as a secondary source for the atmosphere. Dissolved PCBs were probably linked to PCB emissions from contaminated sites and areas of concern. Positive matrix factorization indicated that although volatilized Aroclors (gaseous PCBs) and unaltered Aroclors (dissolved PCBs) dominate in some samples, ongoing non-Aroclor sources such as paints/pigments (PCB 11) and coal/wood combustion showed significant contributions across the lower Great Lakes. Accordingly, control strategies should give further attention to PCBs emitted from current use sources.

SnO₂(β-Bi₂O₃)/Bi₂Sn₂O₇ nanohybrids doped with Pt and Pd nanoparticles: applications in visible light photocatalysis, electrical conductivity and dye-sensitized solar cells

Bi2O3-SnO2 nanocomposites formed at a nominal molar ratio of 3 : 1 and loaded with Pd/Pt nanoparticles synthesized by a sol gel-hydrothermal method with the aid of a template were thoroughly characterized by X-ray diffraction, TEM-EDX, N2 sorptiometry, diffuse reflectance UV-Vis, FTIR, photoluminescence and electrical conductivity. It has been shown that Pd and Pt stimulate the existence of β-Bi2O3 and SnO2, respectively together with the key component Bi2Sn2O7. The photocatalytic results indicate that Pd/β-Bi2O3-Bi2Sn2O7 revealed a remarkable performance for the degradation of methylene blue (MB) dye as compared to the Pt/SnO2-Bi2Sn2O7 and Bi2O3-SnO2 samples in both the UV and visible regions. The enhanced photocatalytic activity of the Pd/β-Bi2O3-Bi2Sn2O7 nanocomposite is primarily attributed to the broad contact between the β-Bi2O3 and Bi2Sn2O7 phases, which indicates high mesoporosity and heterojunction structures resulting in separation efficacy between photo-induced electron-hole pairs. Specifically, the photosensitive β-Bi2O3 is easily excited and released electrons to be accepted by Bi2Sn2O7 and Pd that might be deposited in the interlayer between β-Bi2O3 and Bi2Sn2O7. The degradation mechanism of MB over Pd/β-Bi2O3-Bi2Sn2O7 in the visible region showed that the dye degradation proceeds through evolution of ˙O2(-) and ˙OH radicals as evaluated using photoluminescence and free radical trapping experiments. An insight into the electrical properties including the dielectric constant and impedance of the materials indicates that Pd/β-Bi2O3-Bi2Sn2O7 has the highest conductivity based on increasing the ionic transport and defects at the β-Bi2O3/Bi2Sn2O7 heterojunction. This material displayed an improved photocurrent response of a higher power conversion efficiency, exceeding that of Pt/SnO2-Bi2Sn2O7 and SnBi3 by 50% and 250%, respectively, in dye-sensitized solar cells. Picosecond-resolved photoluminescence (PL) and polarization gated PL anisotropy measurements were combined to clarify the process of FRET from the excited Pd/β-Bi2O3-Bi2Sn2O7 to SD N719. This indicates that the latter structure can be proposed as a multifunctional candidate for use in dye-sensitized solar cells, as an electrical material and as an efficient photocatalyst based on its versatile structure.

Spatial trends, sources, and air-water exchange of organochlorine pesticides in the Great Lakes basin using low density polyethylene passive samplers

Polyethylene passive samplers were deployed during summer and fall of 2011 in the lower Great Lakes to assess the spatial distribution and sources of gaseous and freely dissolved organochlorine pesticides (OCPs) and their air-water exchange. Average gaseous OCP concentrations ranged from nondetect to 133 pg/m(3). Gaseous concentrations of hexachlorobenzene, dieldrin, and chlordanes were significantly greater (Mann-Whitney test, p < 0.05) at Lake Erie than Lake Ontario. A multiple linear regression implied that both cropland and urban areas within 50 and 10 km buffer zones, respectively, were critical parameters to explain the total variability in atmospheric concentrations. Freely dissolved OCP concentrations (nondetect to 114 pg/L) were lower than previously reported. Aqueous half-lives generally ranged from 1.7 to 6.7 years. Nonetheless, concentrations of p,p'-DDE and chlordanes were higher than New York State Ambient Water Quality Standards for the protection of human health from the consumption of fish. Spatial distributions of freely dissolved OCPs in both lakes were influenced by loadings from areas of concern and the water circulation patterns. Flux calculations indicated net deposition of γ-hexachlorocyclohexane, heptachlor-epoxide, and α- and β-endosulfan (-0.02 to -33 ng/m(2)/day) and net volatilization of heptachlor, aldrin, trans-chlordane, and trans-nonachlor (0.0 to 9.0 ng/m(2)/day) in most samples.

Electrical and optical properties of nickel ferrite/polyaniline nanocomposite

Polyaniline-NiFe2O4 nanocomposites (PANI-NiFe2O4) with different contents of NiFe2O4 (2.5, 5 and 50 wt%) were prepared via in situ chemical oxidation polymerization, while the nanoparticles nickel ferrite were synthesized by sol-gel method. The prepared samples were characterized using some techniques such as Fourier transforms infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Moreover, the electrical conductivity and optical properties of the nanocomposites were investigated. Pure (PANI) and the composites containing 2.5 and 5 wt% NiFe2O4 showed amorphous structures, while the one with 50 wt% NiFe2O4 showed a spinel crystalline structure. The SEM images of the composites showed different aggregations for the different nickel ferrite contents. FTIR spectra revealed to the formation of some interactions between the PANI macromolecule and the NiFe2O4 nanoparticles, while the thermal analyses indicated an increase in the composites stability for samples with higher NiFe2O4 nanoparticles contents. The electrical conductivity of PANI-NiFe2O4 nanocomposite was found to increase with the rise in NiFe2O4 nanoparticle content, probably due to the polaron/bipolaron formation. The optical absorption experiments illustrate direct transition with an energy band gap of Eg  = 1.0 for PANI-NiFe2O4 nanocomposite.

Persistent organochlorine pesticide and PCB residues in surface sediments of Lake Qarun, a protected area of Egypt

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in sediment samples collected from 34 locations in Lake Qarun, Egypt to elucidate their concentrations, distribution, possible sources and potential ecological risk. A total of 25 OCPs and 29 PCBs were identified and quantified. OCPs and PCBs were found to be ubiquitous pollutants in the aquatic environment of Lake Qarun, particular near urban areas reflecting the local usage and input of these pollutants. Total concentrations of OCPs and PCBs in sediments ranged from 1.01 to 164.8 ng g(-1) and 1.48 to 137.2 ng g(-1), respectively. Among OCPs, γ-HCH, heptachlor, aldrin, endrin, p,p'-DDE, oxy-chlordane and endosulfan I and II were the most abundant compounds. The composition of PCB congeners was dominated by the tri-, tetra-, penta- and hexa-chlorinated biphenyls. The ratios of certain metabolites (isomers) to their parent compounds (mixtures) indicated there are still new inputs of lindane, endrin, heptachlor and technical endosulfan to Qarun Lake, while the ratios of (p,p'-DDE+p,p'-DDD)/∑p,p'-DDTs indicate earlier usage of DDT. Contamination levels of PCBs and HCHs can be categorized as moderate to high compared to other urbanized regions worldwide. According to established sediment quality guidelines, γ-HCH, endrin and chlordanes would be more concerned OCP species for the ecotoxicological risk in Lake Qarun.

The relationship between endometrial thickness and outcome of medicated frozen embryo replacement cycles

OBJECTIVE

To examine the relationship between endometrial thickness and outcome of medicated frozen-thawed embryo replacement (FER) cycles.

DESIGN

A retrospective observational study.

SETTING

Assisted conception unit at a university hospital.

PATIENT(S)

All patients who underwent an FER cycle between 1997 and April 2006 and met the inclusion criteria.

INTERVENTION(S)

For endometrial preparation, a daily dose of 6 mg of oral E(2) valerate was started on menstrual day 1, and P pessaries (800 mg daily) were administrated when the endometrial thickness had reached 7 mm or more, with ET taking place 2-3 days later. The FER cycles were categorized according to endometrial thickness measurement on the day of P supplementation.

MAIN OUTCOME MEASURE(S)

Implantation, clinical pregnancy, ongoing pregnancy, and live birth rates.

RESULT(S)

In all, 768 consecutive medicated FER cycles were analyzed. The lowest pregnancy rates were associated with endometrial thickness <7 mm (n = 13) and >14 mm (n = 12; 7% in both groups). Significantly higher implantation (19% vs. 12%), clinical pregnancy (30% vs. 18%), ongoing pregnancy (27% vs. 16%), and live birth (25% vs. 14%) rates were achieved in cycles where endometrial thickness was 9-14 mm (n = 386), compared with those in which endometrial thickness was 7-8 mm (n = 357). These differences remained significant after adjusting for confounding variables (adjusted odds ratio [OR] = 1.83 [confidence interval {CI} = 1.3-2.6] for clinical pregnancy, 1.8 [CI = 1.2-2.6] for ongoing pregnancy and 1.9 [CI = 1.3-2.8] for live birth).

CONCLUSION(S)

In medicated FER cycles, an endometrial thickness of 9-14 mm measured on the day of P supplementation is associated with higher implantation and pregnancy rates compared with an endometrial thickness of 7-8 mm.