Performance of an ancillary test for cervical cancer that measures miRNAs and cytokines in serum and cervical mucus.

Currently, human papillomavirus tests and cytology are used to screen for cervical cancer. However, more accurate ancillary screening tests are needed. MicroRNAs (miRNAs) and cytokines are promising biomarkers that are aberrantly expressed in cervical cancer. Therefore, the potential of developing new screening markers based on the levels of miRNAs and cytokines in serum and local mucus samples from the same patients with cervical neoplasia was investigated. miRNA screening was performed by microarray and measurement using real-time reverse-transcriptase PCR. Cytokine were measured using multiplex bead assay, and changes in expressions were analyzed based on disease severity. As lesions progressed, miR-20b-5p, -155-5p, -144-3p, -451a, and -126-3p expression levels were increased in mucus, and miR-16-5p, -223-3p, and -451a expression levels were decreased in serum. Regarding cytokines, IL-6, IL-8, monocyte chemoattractant protein-1, Eotaxin, interferon-γ, and RANTES were increased, whereas granulocyte-colony-stimulating factor (G-CSF) was significantly decreased in mucus. miRNAs and cytokines in serum did not have high diagnostic accuracy. However, a combination of miR-20b-5p, -451a, -126-3p, Eotaxin, as well as G-CSF in mucus samples, had high diagnostic accuracy with an area under the receiver operating characteristic curve of 0.989 (0.979-0.999). Our results suggest that using mucus for this ancillary test is more beneficial than serum.

Guideline for gynecological practice in Japan: Japan Society of Obstetrics and Gynecology and Japan Association of Obstetricians and Gynecologists 2023 edition.

Twelve years after the first edition of The Guideline for Gynecological Practice, which was jointly edited by The Japan Society of Obstetrics and Gynecology and The Japan Association of Obstetricians and Gynecologists, the 5th Revised Edition was published in 2023. The 2023 Guidelines includes 5 additional clinical questions (CQs), which brings the total to 103 CQ (12 on infectious disease, 30 on oncology and benign tumors, 29 on endocrinology and infertility and 32 on healthcare for women). Currently, a consensus has been reached on the Guidelines, and therefore, the objective of this report is to present the general policies regarding diagnostic and treatment methods used in standard gynecological outpatient care that are considered appropriate. At the end of each answer, the corresponding Recommendation Level (A, B, C) is indicated.

Initial experience and surgical outcomes of robotic-assisted total hysterectomy using the da Vinci SP surgical system.

INTRODUCTION: The da Vinci SP surgical system is a surgical platform capable of implementing robotic-assisted surgery through a single port and was first introduced in Japan at our hospital. In this paper, we describe our experience of the initial introduction of the da Vinci SP surgical system and its surgical outcomes. This is the first report on the surgical outcomes of using da Vinci SP, and its comparison with the conventional system in Japan. METHODS: After developing an application for a highly difficult new medical technology in-house, we compared the surgical outcomes (median values) of 15 patients who had undergone total hysterectomy at our hospital using the da Vinci SP (1-port) system (SP group) for uterine myoma after March 2023 and of 154 patients who underwent total hysterectomy using the conventional da Vinci Xi (four ports) system (Xi group) for uteri weighing <500 g. RESULTS: The results of the comparison of the characteristics between 15 patients in the SP group and 154 patients in the Xi group were as follows: uterus weight (g): 230 (90-500) versus 222 (55-496) (p = .35); surgical time (minutes): 199 (171-251) versus 198 (88-387) (p = .63); intraoperative blood loss (mL): 13 (5-82) versus 20 (2-384) (p = .17); and rate of surgical complication (%): 0.0 versus 1.3 (p = .66). The data indicated a comparable weight of the resected uterus, surgical time, intraoperative blood loss, and rate of surgical complications between the two groups. CONCLUSION: Robotic-assisted total hysterectomy using the da Vinci SP surgical system allowed clinicians to safely perform surgeries according to the conventional systems.

Metabolomic and microbiome analysis of cervicovaginal mucus in in vitro fertilization-embryo transfer: Toward predicting pregnancy success.

Purpose: In the context of in vitro fertilization-embryo transfer (IVF-ET), factors other than egg quality may be key determinants of treatment success, in particular, maternal factors related to uterine endometrial receptivity and unidentified factors. We therefore aimed to analyze the metabolome and microbiome in IVF-ET patients who did and did not achieve pregnancy. Methods: Cervicovaginal mucus was collected from patients undergoing IVF-ET. Metabolite analysis was conducted by liquid chromatography-mass spectrometry and the microbiota were determined by the polymerase chain reaction using universal 16S-rRNA gene bacterial primers by MiSeq sequencing. Patients were classified as pregnant (N = 10) or nonpregnant (N = 13). Metabolic pathways were examined by MetaboAnalyst. Results: Three metabolic pathways, including alanine-aspartate-glutamate metabolism, arginine biosynthesis, and cysteine-methionine metabolism, were commonly decreased at the time of embryo transfer irrespective pregnant outcomes. Notably, pyruvate was decreased in the pregnant group. Amino acid metabolites showed inverse correlations with the presence of anaerobic microbiota in the nonpregnant group. Conclusions: Metabolism decreased during embryo transplantation, with a notable decrease in pyruvate metabolism, particularly in patients who became pregnant. The behavior of metabolites in the pregnant and nonpregnant groups suggests that metabolome analysis in the cervicovaginal mucus may be a diagnostic marker for predicting pregnancy.

Rare recurrence of a multilocular cystic leiomyoma following myomectomy.

Multilocular cystic leiomyomas rarely develop following myomectomy. To the best of our knowledge, there are no published reports on recurrent multilocular cystic leiomyoma following myomectomy. We here present such a case. A 45-year-old woman visited our outpatient clinic because of heavy vaginal bleeding. She underwent laparoscopic myomectomy for a solid mass in the uterine cavity. Subsequent pathological examination of the operative specimen revealed a tumour with well-demarcated borders and spindle cells arranged in intersecting fascicles. Seven days postoperatively, ultrasonography revealed a cystic lesion. Magnetic resonance imaging performed 28 months postoperatively revealed a large, well-defined, multilocular cystic mass that was homogeneously hyperintense on T2-weighted images on the exterior of the uterus. Abdominal hysterectomy was performed. On pathological examination of the operative specimen, she was found to have a leiomyoma with marked cystic degeneration. Incomplete excision of a multilocular cystic leiomyoma may result in recurrence in the form of a large cystic mass. Clinical differentiation between a multilocular cystic leiomyoma and an ovarian tumour may be difficult. Complete resection of a uterine multilocular cystic lesion prevents recurrence.

Nomogram for predicted probability of cervical cancer and its precursor lesions using miRNA in cervical mucus, HPV genotype and age.

Cervical cancer is the fourth most common cancer in women worldwide. Although cytology or HPV testing is available for screening, these techniques have their drawbacks and optimal screening methods are still being developed. Here, we sought to determine whether aberrant expression of miRNAs in cervical mucus could be an ancillary test for cervical neoplasms. The presence of miRNAs in 583 and 126 patients (validation and external cohorts) was determined by real-time RT-PCR. Performance of a combination with five miRNAs (miR-126-3p, -451a -144-3p, -20b-5p and -155-5p) was estimated by ROC curve analysis. Predicted probability (PP) was estimated by nomograms comprising -ΔCt values of the miRNAs, HPV genotype and age. A combination of five miRNAs showed a maximum AUC of 0.956 (95% CI: 0.933-0.980) for discriminating cancer. Low PP scores were associated with good prognosis over the 2-year observation period (p < 0.05). Accuracy for identifying cancer and cervical intraepithelial neoplasia (CIN) 3 + by nomogram was 0.983 and 0.966, respectively. PP was constant with different storage conditions of materials. We conclude that nomograms using miRNAs in mucus, HPV genotype and age could be useful as ancillary screening tests for cervical neoplasia.

Changes to the cervicovaginal microbiota and cervical cytokine profile following surgery for cervical intraepithelial neoplasia.

Persistent HPV infection associated with immune modulation may result in high-grade squamous intraepithelial lesions (CIN)2/3. Currently, there is little information on the cervicovaginal microbiome, local cytokine levels and HPV infection related to CIN. Follow-up of patients after local surgery provides an opportunity to monitor changes in the cervicovaginal environment. Accordingly, we undertook this longitudinal retrospective study to determine associations between HPV genotypes, cervicovaginal microbiome and local cytokine profiles in 41 Japanese patients with CIN. Cervicovaginal microbiota were identified using universal 16S rRNA gene (rDNA) bacterial primers for the V3/4 region by PCR of genomic DNA, followed by MiSeq sequencing. We found that Atopobium vaginae was significantly decreased (p < 0.047), whereas A. ureaplasma (p < 0.022) increased after surgery. Cytokine levels in cervical mucus were measured by multiplexed bead-based immunoassays, revealing that IL-1ß (p < 0.006), TNF-α (p < 0.004), MIP-1α (p < 0.045) and eotaxin (p < 0.003) were significantly decreased after surgery. Notably, the level of eotaxin decreased in parallel with HPV clearance after surgery (p < 0.028). Thus, local surgery affected the cervicovaginal microbiome, status of HPV infection and immune response. Changes to the cervicovaginal microbiota and cervical cytokine profile following surgery for cervical intraepithelial neoplasia may be important for understanding the pathogenesis of CIN in future.

Upregulation of CIP2A in estrogen depletion-resistant breast cancer cells treated with low-dose everolimus.

Everolimus (EVE), an inhibitor of mammalian target of rapamycin, is an emerging second-line therapeutic option for hormone therapy-resistant breast cancers. However, some patients do not respond to EVE, whereas in others it exacerbates the disease. Cellular inhibitor of protein phosphatase 2A (CIP2A) is a human oncoprotein that can promote cancer cell growth and apoptosis resistance. Although CIP2A is upregulated in hormone-related cancers, such as breast cancer, little is known about potential anti-tumor effects of downregulating CIP2A. As a model to study the resistance of breast cancer cells to hormone treatment, we previously established clones of long-term estrogen depletion-resistant MCF-7 (LTED) cells. Here, we selected three clones highly responsive to EVE and three clones poorly responsive to EVE. When cells were treated with EVE, CIP2A mRNA expression was decreased in highly responsive EVE clones (DC-cells) whereas it was increased in poorly responsive EVE clones (IC-cells). Using Kaplan-Meier survival plots, we report that high expression of CIP2A was associated with significantly reduced overall survival in patients with luminal A breast cancer. In IC-cells, cell growth was enhanced upon EVE treatment whereas an EVE range of 0.1-100 nm decreased growth in DC-cells. The mRNA expression of genes involved in epithelial-mesenchymal transition (EMT) such as CDH1, CLDN3, and CK19 was significantly decreased in IC-cells, but remained unchanged in DC-cells. These findings highlight a relationship between CIP2A and EMT in the intrinsic resistance of hormone therapy-resistant breast cancers to EVE.

MicroRNA­126­3p suppresses HeLa cell proliferation, migration and invasion, and increases apoptosis via the PI3K/PDK1/AKT pathway.

We previously reported that relative to normal cervical mucus, microRNA 126­3p (miR­126­3p) is present in significantly greater amounts in the cervical mucus of patients with overt cervical cancer or precursor lesions. Here, we investigated the effects of enforced miR­126­3p expression in the cervical cancer cell line, HeLa, on proliferation, migration, invasion, apoptosis and protein expression. We transfected HeLa cells with miR­126­3p miRNA and found that proliferation, migration and invasion by cell counting, wound healing, cell migration and invasion assay were significantly reduced in these cells relative to those transfected with a negative control mimic. The levels of phosphoinositide 3 kinase (PI3K), phosphorylated 3­phosphoinositide­dependent protein kinase­1 (p­PDK1) and p­AKT proteins were lower in the miR­126­3p­transfected cells. Phosphorylated 70S6K (p­p70S6K), phosphorylated glycogen synthase kinase 3ß (p­GSK3ß), phosphorylated S6K (p­S6K), cyclin D1, phosphorylated p21­activated kinase 1 (p­PAK1), Rho associated coiled­coil containing protein kinase 1 (ROCK1), myotonic dystrophy­related CDC42­binding kinases α (MRCKα) and phospholipase C γ1 (p­PLCγ1) were also downregulated. This suggests that downstream effectors of the PI3K/PDK1/AKT pathway are targets for inhibition by miR­126­3p. In contrast, apoptotic­related proteins including the BCL­2­associated agonist of cell death (Bad), B­cell lymphoma­extra­large (Bcl­xL) and BCL­2­associated X (Bax), were all upregulated by miR­126­3p, resulting in increased caspase 3/7 activity and apoptosis. Thus, enforced expression of miR­126­3p inhibited cell migration and invasion and also induced apoptosis by regulating the PI3K/PDK1/AKT pathway in HeLa cells. Hence, high levels of miR­126­3p may inhibit cervical carcinogenesis, and targeting the PI3K/PDK1/AKT pathway via miR­126­3p could represent a new approach for treating patients with cervical cancer.

Lack of association of ovariectomy-induced obesity with overeating and the reduction of physical activities.

Obesity commonly occurs in postmenopausal women, increasing the risk of various diseases. Estrogen can prevent obesity by activating lipid metabolism and suppressing depressive behavior. However, the reasons for obesity in postmenopausal women are not clearly elucidated. To mimic the effect of estrogen decline in postmenopausal women, we analyzed the behavior and the lipid metabolism-related genes, PPARγ and CD36 in ovariectomized (OVX) mice. The OVX mice showed increased visceral fat mass and PPARγ and CD36 expression in the visceral fat. In contrast, they were not significantly affected in terms of physical activity and food intake. Further, subcutaneous supplementation of estrogen effectively suppressed the increase in subcutaneous and visceral fat mass in OVX mice. We conclude that obesity in postmenopausal women is unlikely to be caused by overeating and reduction in physical activity, and subcutaneous supplementation of estrogen is an effective strategy to prevent obesity in postmenopausal women.

Cytokine expression profiles in cervical mucus from patients with cervical cancer and its precursor lesions.

Human papillomavirus (HPV) infection can persist in the cervical epithelium without provoking a strong host immune response, leading to the development of cervical cancer. Cytokines, which mediate innate and adaptive immune activities, are secreted in the cervical mucus; however, there is currently no appropriate method for assessing cytokine levels in mucus specimens. Here, we employed multiplexed bead-based immunoassays to examine cytokine levels in cervical mucus using both weighted-volume and total protein concentration methods to adjust for different specimen volumes in individual patients. Out of 18 cytokines initially examined in the primary cohort patient group (n = 28), 14 were detected in more than 10% of the samples. Of these 14 cytokines, expression levels of interferon (IFN)-γ, granulocyte-macrophage colony-stimulating factor (GM-CSF), RANTES, and eotaxin were significantly increased with the disease severity in the secondary cohort patient group (n = 235). We also examined associations between cytokine levels and clinical parameters, such as cytology and HPV genotype. Of the 14 cytokines, granulocyte colony-stimulating factor (G-CSF) was downregulated in HPV-positive specimens. Examination of co-expression patterns of cytokines in relation to HPV infection status revealed that several pairs of cytokines were simultaneously upregulated in HPV-positive cases, including INF-γ and interleukin (IL)-17A, GM-CSF and monocyte chemoattractant protein-1 (MCP-1), GM-CSF and RANTES, IL-17A and RANTES, and MCP-1 and eotaxin. Interestingly, upregulation of GM-CSF and RANTES might reflect a shift in immuno-regulatory cytokines in HPV-positive specimens, potentially associated with more severe cervical neoplasia.

Identification of miRNAs in cervical mucus as a novel diagnostic marker for cervical neoplasia.

microRNAs (miRNAs) play important roles in regulation of gene expression during cervical carcinogenesis. We investigated expression profiles of miRNAs in cervical cancer and its precursor lesions by utilizing cervical mucus. Cervical mucus was collected from 230 patients with a normal cervix, cervical intraepithelial neoplasia (CIN), squamous cell carcinoma (SCC), or adenocarcinoma (AD). The levels of miRNA in the mucus were quantified by miRNA array and real-time reverse-transcriptase polymerase chain reaction (RT-PCR). The performance for detecting diseases was statistically analysed. The expression of miRNAs was further validated in the surgical tissues of enrolled patients. Four miRNAs (miR-126-3p, -20b-5p, -451a, and -144-3p) were significantly up-regulated in SCC and AD compared with normal, and their expression levels correlated with disease severity and high-risk human papillomavirus infection. Receiver operating characteristic curve analyses revealed that the area under the curve values for miR-126-3p, -20b-5p, -451a, and -144-3p were 0.89, 0.90, 0.94, and 0.93, respectively, for SCC plus AD compared with normal, showing high accuracy of cancer detection. Real-time RT-PCR analyses confirmed the expression of these four miRNAs in frozen tissues from cervical cancer. miR-126-3p, -20b-5p, -451a, and -144-3p in cervical mucus are promising biomarkers for cervical cancer and high-grade CINs.

Forskolin increases the effect of everolimus on aromatase inhibitor-resistant breast cancer cells.

Aromatase inhibitor (AI) resistance is a major obstacle in the treatment of estrogen receptor-positive breast cancer. Everolimus (EVE) ameliorates AI-resistant breast cancer and is therefore used in cancer treatment. However, some patients show resistance to EVE. Here, we used 30 clones of long-term estrogen-deprived (LTED) MCF-7 cells as a model of AI-resistant breast cancer. We examined changes in protein phosphatase type 2A (PP2A) and cancerous inhibitor of PP2A (CIP2A), a negative regulator of PP2A, in LTED cells treated with EVE. In LTED cells with high sensitivity to EVE, CIP2A expression decreased at low EVE concentrations; however, in LTED cells poorly sensitive to EVE, CIP2A and PP2A did not change upon exposure to EVE. Therefore, we hypothesized that there is a relation between expression of CIP2A and sensitivity to EVE. Knockdown of CIP2A increased the sensitivity to EVE in three clones poorly sensitive to EVE. Additionally, we found that treatment with FSK, which activates PP2A, increased the sensitivity of the cells to EVE. Our data point to CIP2A and PP2A as novel therapeutic targets for AI-resistant breast cancer.

Preimplantation genetic diagnosis/screening by comprehensive molecular testing.

Although embryo screening by preimplantation genetic diagnosis (PGD) has become the standard technique for the treatment of recurrent pregnancy loss in couples with a balanced gross chromosomal rearrangement, the implantation and pregnancy rates of PGD using conventional fluorescence in situ hybridization (FISH) remain suboptimal. Comprehensive molecular testing, such as array comparative genomic hybridization and next-generation sequencing, can improve these rates, but amplification bias in the whole genome amplification method remains an obstacle to accurate diagnosis. Recent advances in amplification procedures combined with improvements in the microarray platform and analytical method have overcome the amplification bias, and the data accuracy of the comprehensive PGD method has reached the level of clinical laboratory testing. Currently, comprehensive PGD is also applied to recurrent pregnancy loss due to recurrent fetal aneuploidy or infertility with recurrent implantation failure, known as preimplantation genetic screening. However, there are still numerous problems to be solved, including misdiagnosis due to somatic mosaicism, cell cycle-related background noise, and difficulty in diagnosis of polyploidy. The technology for comprehensive PGD also requires further improvement.

Relationship between detection of the cervical gland area during the late third trimester and necessity for induction of labor to prevent post-term delivery.

OBJECTIVES: With the maturation of the cervical canal during pregnancy, the cervical gland area (CGA) as observed on transvaginal ultrasonography is gradually obscured. The aim of this study was to elucidate the significance of CGA in the late third trimester as a determinant of the outcome of labor. METHODS: We investigated 123 primiparous women with singleton pregnancies at 36-41 weeks' gestation. The women were divided into two groups: a normal delivery group (93 women), which had vaginal delivery without medical intervention, and an induction of labor group (30 women), which required induction of labor after 41 weeks and 0 day. At outpatient prenatal checkups, the Bishop score (BS) was assessed by pelvic examination, and cervical length (CL) and CGA were evaluated by transvaginal ultrasonography. The relationship between each parameter and induction of labor was retrospectively determined and compared. RESULTS: Time-dependent assessment of each outcome determinant showed that the CGA detection rate was higher and the CL was longer in the induction of labor group from 3 weeks to 1 week before delivery at a significant level (P < 0.05); however, the BS was significantly lower in the induction of labor group only at 1 week before delivery (P < 0.05). When multiple logistic regression analysis of the necessity of induction of labor was conducted using BS, CL, and CGA parameters as explanatory variables at 1 week before delivery, CGA alone was shown to be an independent predictor of induction of labor (OR = 6.1, 95 % CI 2.3-16.2). CONCLUSION: The present study suggests that in the late third trimester, evaluation of CGA with transvaginal ultrasonography is most useful in predicting the necessity of induction of labor to prevent post-term delivery.

Asymptomatic synchronous quintuple primary cancers.

We encountered a 46-year-old woman with synchronous quintuple primary cancers. She did not present with any symptoms, and her tumors were discovered at a gynecological screening. She had clear cell adenocarcinoma of the right ovary, moderately differentiated endometrioid adenocarcinoma of the endometrium, moderately differentiated adenocarcinoma of the ascending colon, well-differentiated adenocarcinoma of the rectum, and poorly differentiated papillary adenocarcinoma of the left lung. A fluorodeoxyglucose-positron emission tomography and other imaging techniques were extremely useful for the diagnosis of multiple primary cancers. Moreover, MSH2 protein expression was absent in the tumors of the ovary, endometrium, ascending colon, and rectum, while the rectal cancer also lacked MLH1 protein. These findings suggested that an abnormality of DNA mismatch repair genes was responsible for carcinogenesis.

A case of primary uterine cervical neuroendocrine tumor with meningeal carcinomatosis confirmed by diagnostic imaging and autopsy.

Primary uterine cervical neuroendocrine tumors are rare, but affect relatively young women and the prognosis is poor despite multidisciplinary treatment. The incidence of meningeal carcinomatosis arising from malignant tumors of the uterine cervix is extremely low, only two patients with meningeal carcinomatosis arising from a uterine cervical neuroendocrine tumor have been reported in the English literature. Moreover, there have been no reports in which this was confirmed at autopsy. We encountered a pregnant woman aged 33 years who was diagnosed as having atypical carcinoid of the uterine cervix after radical surgery. Despite multidrug chemotherapy (paclitaxel + etoposide + cisplatin and irinotecan + carboplatin), the patient developed multiple organ metastases. Although there was no metastasis to the brain parenchyma or the spinal cord parenchyma, the patient also developed meningeal carcinomatosis. Whole-brain radiation therapy was performed, but was ineffective. The patient died at 19 months after her initial operation and 10 days after diagnosis of meningeal carcinomatosis. The presence of meningeal carcinomatosis was confirmed at autopsy.

Two cases of ectopic ovary and one case of potential ectopic ovary.

Ectopic ovary is a rare gynecologic entity. A variety of synonymous terms such as ectopic ovary, supernumerary ovary, accessory ovary, and autoamputation of the ovary have been used to describe this condition. The etiology for ectopic ovary has not been elucidated, but several mechanisms have been proposed. They are categorized as either congenital (embryologically derived) or acquired. This report presents two cases of ectopic ovary resulting from different causes and one case of potential ectopic ovary.

[Anti-steroid hormones for uterine cancer].

Endometrial cancer is an estrogen-dependent tumor with increasing incidence in recent years. It can be classified into two types: the more common type 1 tumors are estrogen-dependent, develop in relatively younger patients, and are associated with a relatively good prognosis; while type 2 tumors are estrogen-independent, develop in relatively older patients and are associated with a poorer prognosis. On the other hand, with the increase in breast cancer patients in recent years and with the resulting similar increase in patients on oral tamoxifen treatment, there has been a problematic rise in the incidence of endometrial cancers induced by tamoxifen use. This has necessitated a need for careful observation of these patients as tamoxifen-related endometrial cancers are often type 2 cancers and thus present with a poorer prognosis. A large number of hormonal treatments have been used in the treatment of endometrial cancer; however, only progestin derivatives have demonstrated any effect towards endometrial cancer to date. In general, progestin therapy is used only for fertility-preserving purposes in younger patients. These patients must fulfill the indications of well-differentiated endometrioid adenocarcinoma of Stage Ia; in these patients, medroxyprogesterone acetate (MPA) 400-600 mg/day is administered and treatment effects are evaluated by endometrial biopsy every 8 weeks.

Chemical removal of zona pellucida versus laser assisted hatching after repeated failures of assisted reproductive technology.

Background and Aims: To evaluate outcomes after zona pellucida removal by pronase or laser assisted hatching in women with repeated assisted reproduction failures. Methods: Of 389 procedures (January 2004 to November 2005), 203 control cycles had an intact zona, 116 cycles had chemical removal of the zona and 70 cycles had laser assisted hatching. Rates of pregnancy, implantation and abortion were compared, and pregnancy rate was secondarily evaluated for fresh or frozen-thawed blastocysts. Results: Pregnancy rates were 33.5% (68/203) for controls, 29.3% (34/116) for chemical removal and 30.0% (21/70) for laser. Implantation rates were 24.8% (68/274) for controls, 21.8% (34/156) for chemical removal and 30.0% (21/105) for laser. There were no significant differences among groups. Abortion rates were 15.6% (10/64) for controls, 13.9% (5/36) for chemical removal and 14.3% (3/21) for laser. No difference was observed by blastocyst type for control or laser assisted hatching cycles. In the chemical removal group, both pregnancy and implantation rates were higher for frozen-thawed blastocysts than for fresh blastocysts. (41.5%vs 13.2% and 30.7%vs 11.1%, respectively). Conclusions: Assisted hatching did not show a significant benefit. Chemical zona pellucida removal might increase pregnancy rates for frozen-thawed blastocysts. (Reprod Med Biol 2006; 5: 263-267).