Microfluidic thermotaxic selection of highlymotile sperm and in vitro fertilization

The selection of the most motile and functionally competent sperm is an essential basis for in vitro fertilization(IVF)and normal embryonic development.Widely adopted clinical approaches for sperm sample processing intensely rely on centrifugation and wash steps that may induce mechanical damage and oxidative stress to sperm.Although a few microfluidic sperm sorting devices may avoid these adverse effects by exploiting intrinsic guidance mechanisms of sperm swimming,none of these approaches have been fully validated by clinical-grade assessment criteria.In this study,a microfluidic sperm sorting device that enables the selection of highly motile and functional sperm via their intrinsic thermotaxis is presented.Bioinspired by the temperature microenvironment in the fallopian tube during natural sperm selection,a microfluidic device with controllable temperature gradients along the sperm separation channel was designed and fabricated.This study investigated the optimal temperature conditions for human sperm selection and fully characterized thermotaxis-selected sperm with 45 human sperm samples.Results indicated that a temperature range of 35–36.5℃along the separation channel significantly improves human sperm motility rate((85.25±6.28)%vs.(60.72±1.37)%;P=0.0484),increases normal sperm morphology rate((16.42±1.43)%vs.(12.55±0.88)%;P<0.0001),and reduces DNA fragmentation((7.44±0.79)%vs.(10.36±0.72)%;P=0.0485)compared to the nonthermotaxis group.Sperm thermotaxis is species-specific,and selected mouse sperm displayed the highest motility in response to a temperature range of 36–37.5℃ along the separation channel.Furthermore,IVF experiments indicated that the selected sperm permitted an increased fertilization rate and improved embryonic development from zygote to blastocyst.This microfluidic thermotaxic selection approach will be translated into clinical practice to improve the IVF success rate for patients with oligozoospermia and asthenozoospermia.

Association between Exposure of Rare Earth Elements and Outcomes of In Vitro Fertilization-Embryo Transfer in Beijing

Objective The study aimed to investigate the impact of rare earth elements(REEs)exposure on pregnancy outcomes of in vitro fertilization-embryo transfer(IVF-ET)by analyzing samples from spouses.Methods A total of 141 couples were included.Blood and follicular fluid from the wives and semen plasma from the husbands,were analyzed for REEs using inductively coupled plasma mass spectrometry(ICP-MS).Spearman's correlation coefficients and the Mann–Whitney U test were used to assess correlations and compare REE concentrations among three types of samples,respectively.Logistic models were utilized to estimate the individual REE effect on IVF-ET outcomes,while BKMR and WQS models explored the mixture of REE interaction effects on IVF-ET outcomes.Results Higher La concentration in semen(median 0.089 ng/mL,P=0.03)was associated with a lower fertilization rate.However,this effect was not observed after artificial selection intervention through intracytoplasmic sperm injection(ICSI)(P=0.27).In semen,the REEs mixture did not exhibit any significant association with clinical pregnancy.Conclusion Our study revealed a potential association between high La exposure in semen and a decline in fertilization rate,but not clinical pregnancy rate.This is the first to report REEs concentrations in follicular fluid with La,Ce,Pr,and Nd found at significantly lower concentrations than in serum,suggesting that these four REEs may not accumulate in the female reproductive system.However,at the current exposure levels,mixed REEs exposure did not exhibit reproductive toxicity.

A nomogram predicting clinical pregnancy in the first fresh embryo transfer for women undergoing in vitro fertilization and intracytoplasmic sperm injection(IVF/ICSI) treatments

The extent to which factors affect the probability of clinical pregnancy in the first fresh embryo transfer after assisted conception is unknown.In order to examine the predictors of clinical pregnancy,a retrospective cohort study was launched between January 1,2013 and December 31,2016 in four infertility clinics including 19837 in vitro fertilization and intracytoplasmic sperm injection(IVF/ICSI)fresh cycles with known outcomes and relevant records.A multivariable logistic regression was used to select the most significant predictors in the final nomogram for predicting clinical pregnancy.Furthermore,the model was validated by an independent validation set and the performance of the model was evaluated by the receiver operating characteristic(ROC)curves along with the area under the ROC curve(AUC)and calibration plots.In a training set including 17854 participants,we identified that female age,tubal factor,number of embryos transferred,endometrial thickness and number of good-quality embryos were independent predictors for clinical pregnancy.We developed a nomogram using these five factors and the predictive ability was 0.66 for AUC(95%CI=0.64−0.68),which was independently validated in the validation set(AUC=0.66,95%CI=0.65−0.68).Our results show that some specific factors can be used to provide infertile couples with an accurate assessment of clinical pregnancy following assisted conception and facilitate to guide couples and clinicians.

Case Report: Acupuncture Treatment in Female Patient Undergoing IVF (In Vitro Fertilization)

Acupuncture as part of the Traditional Chinese Medicine (TCM) is used for a very long time as a treatment for infertility issues. Through the specific acupoints located on the meridians, with the acupuncture treatment the Qi and blood flow can be regulated and the whole body energy balanced. Acupuncture increases the blood flow to the ovaries and uterus, improving the implantation condition, the ovarian and follicular function and balancing the hormones. In this research, it is presented a case of 32-year-old woman who has already had an unsuccessful in vitro cycle, 6 months before starting acupuncture treatments. The patient has done 8 acupuncture treatments in our clinic before starting the second cycle of embryo transfer. The treatments were done twice monthly in a period of 4 months. Before starting the first embryo transfer, the FSH was at high levels: 11 mIU/mL (1.98 - 11.6). After the acupuncture treatments, it was normalized to 8.11 mIu/mL. The second embryo transfer was successful and so far the patient is in good health. Acupuncture treatment as part of the TCM, helps the female reproductive system to function properly, especially in an important periods of fertilization, keeping the pregnancy rates high.

Effects of Cumulus Cells on in vitro Fertilization of Bovine

[Objective] The aim was to explore the effect of cumulus cells on the in vitro fertilization of in vitro matured bovine oocytes. [Method] The in vitro matured oocytes were divided into three groups of cumulus cells removal, partial removal and no removal. [Result] In the co-culture with cumulus cells, the oocytes of the removal group had higher cleavage rate and blastocyst rate （74.4%±4.1, 53.7%±5.1） than those of the no removal group （72.7%±5.1, 52.4%±3.5）, but the difference was not significant （P〉0.05）, while both groups had better performances than the re- moval group （39.6%±4.5, 18.8%±4.6） with the difference reaching the significant level （P〈0.05）. All the three groups showed significant difference with the control. The combination of cumulus cells and melatonin achieved the best effects as the cleavage rate and blastocyst rate of the partial removal group （79.8%±3.7, 56.5%±5.1） were better than those of the no removal group （78.2%±2.6, 55.8%±4.6）, and the difference was not significant, while both group had better performances than the removal group （48.3%±5.5, 22.7%±4.3） and the control group with the differences reaching the significant level （P〈0.05）. [Conclusion] The study provided technical support for the production of dairy cows and beef cattle.

In Vitro Fertilization of Angiosperms-10-Year Effort in China

This review gives a brief retrospect to the development on in vitro fertilization (IVF) of angiosperms in China. During the last decade Chinese scientists put great enthusiasm and efforts on IVF system construction and built up notable contributions to the flourish of this field. Keeping pace with international development and participating international cooperation in the field of IVF, Chinese scientists have now focused on the investigation of basic mechanism relevant to possible gamete interaction, egg cell activation and early embryogenesis by IVF. In vitro manipulation techniques are combined with cytological and molecular biological approaches to unveil the double fertilization mysteries.

In Vitro Fertilization in Maize and Tobacco: The Fusion Patterns During Sexual Cell Fusion

Large scale of sexual cell fusion was carried out in order to observe the fusion pattern during in vitro fertilization with special interest in the influence of cell volume on the membrane behavior. Three patterns could be recognized in sexual cell fusion, which was supported by fluorescent microscopy with the aid of video enhanced system and cooled CCD. It was found that the fusion pattern and cell membrane behavior were related to the cell volume ratio of two fusing cells. The results reported here might be useful for interpreting and evaluating data from in vitro fertilization experiments and for explaining male cytoplasm exclusion during fertilization.

卵巢储备功能低下患者血清AMH、Betatrophin水平与卵巢反应性、IVF-ET妊娠结局关系

目的:探讨卵巢储备功能低下(DOR)患者血清抗苗勒管激素(AMH)、促代谢因子(Betatrophin)水平与卵巢反应性及体外受精-胚胎移植(IVF-ET)妊娠结局的关系。方法:收集2019年12月-2022年12月在本院行IVF-ET的DOR患者137例临床资料,根据卵巢反应性将患者分为低反应组(n=112)、正常反应组(n=16)、高反应组(n=9);根据妊娠结局将患者分为妊娠成功组(n=44)和妊娠失败组(n=93)。酶联免疫吸附法检测血清AMH、Betatrophin水平,受试者工作特性(ROC)曲线评估2项指标预测IVF-ET妊娠结局价值;多因素logistic回归分析影响妊娠的因素。结果:低反应组、正常组、高反应组血清AMH水平(0.49±0.13 ng/ml、0.98±0.21 ng/ml、1.05±0.26 ng/ml)依次升高,血清Betatrophin水平(156.95±16.33 pg/ml、112.17±13.42 pg/ml、92.64±11.03 pg/ml)依次降低;妊娠成功组血清AMH水平(1.07±0.36 ng/ml)高于妊娠失败组(0.34±0.19 ng/ml),Betatrophin水平(136.29±14.42 pg/ml)低于妊娠失败组(216.16±21.05 pg/ml)(均P<0.05)。血清AMH、Betatrophin预测DOR患者IVF-ET妊娠结局的曲线下面积(AUC)(95%CI)别为0.857、0.771,两项指标联合预测的AUC为0.904。多因素logistic回归分析显示,卵泡刺激素/促黄体生成素比值≥2、卵巢低反应、AMH≤0.71 ng/ml、Betatrophin≥176.23 pg/ml是DOR患者IVF-ET妊娠失败的独立危险因素(P<0.05)。结论:血清AMH、Betatrophin水平与DOR患者卵巢反应性、IVF-ET妊娠结局有关,二者有望作为预测DOR患者IVF-ET妊娠结局的生物标记物。

Intracytoplasmic sperm injection in cases with a history of in vitro fertilization failure

<abstract>Aim: To evaluate the effect of intracytoplasmic sperm injection (ICSI) in the management of cases with a history of conventional in vitro fertilization (IVF) failure. Methods: Two groups of patients, 19 with normal semen parameters and a history of IVF failure (metaphase Ⅱ oocytes: 0~30 %) and 28 with severe male factor infertility received ICSI technology during the same period. Ovarian stimulation was achieved by conventional procedure. Transvaginal ultrasound-guided oocyte collection was done 35~37 h after human chorionic gonadotrophin (hCG) injection. Only metaphase Ⅱ oocytes were selected for microinjection. Results: Fertilization was achieved with ICSI in all the patients. The fertilization rate (75.6 %±21.1 % vs. 73.9 %±19.2 %), cleavage rate (85.1 %±19.3 % vs. 82.7 %±22.1 %), clinical pregnancy rate per embryo transfer cycle (31.6 % vs. 28.6 %) and implantation rate per embryo (15.3 % vs. 14.4 %) did not differ significantly between the two groups. Conclusion: ICSI is a valuable method for couples with a history of IVF failure. These patients may have a similar ICSI result as in severe male infertility.

A highly homozygous and parthenogenetic human embryonic stem cell line derived from a one-pronuclear oocyte following in vitro fertilization procedure

Homozygous human embryonic stem cells （hESCs） are thought to be better cell sources for hESC banking because their human leukocyte antigen （HLA） haplotype would strongly increase the degree of matching for certain populations with relatively smaller cohorts of cell lines. Homozygous hESCs can be generated from parthenogenetic embryos, but only heterozygous hESCs have been established using the current strategy to artificially activate the oocyte without second polar body extrusion. Here we report the first successful derivation of a human homozygous ESC line （chHES- 32） from a one-pronuclear oocyte following routine in vitro fertilization treatment, chHES-32 cells express common markers and genes with normal hESCs. They have been propagated in an undifferentiated state for more than a year （〉P50） and have maintained a stable karyotype of 46, XX. When differentiated in vivo and in vitro, chHES-32 cells can form derivatives from all three embryonic germ layers. The almost undetectable expression of five paternally expressed imprinted genes and their HLA genotype identical to the oocyte donor indicated their parthenogenetic origin. Using genome-wide single-nucleotide polymorphism analysis and DNA fingerprinting, the homozygosity of chHES-32 cells was further confirmed. The results indicated that ‘ unwanted＇ one-pronuclear oocytes might be a potential source for human homozygous and parthenogenetic ESCs, and suggested an alternative strategyfor obtaining homozygous hESC lines from parthenogenetic haploid oocytes.

Fertilization of IVF/ICSI Using Sibling Oocytes from Couples with Subfertile Male or Unexplained Infertility

The significance of the performance of conventional in vitro fertilization and intracytoplasmic sperm injection (IVF/ICSI) using sibling oocytes from couples with subfertile male or unexplained infertility was evaluated. A total of 410 sibling oocyte cumulus-corona complexes (OCCC) from 21 couples with subfertile male (group A) and 11 unexplained infertile couples (group B) were randomly divided, in order of retrieval, into two groups inseminated either by conventional IVF or by ICSI. The treatment outcomes and the influence of infertility factors on fertilization in each group were compared. The results showed that although the two pronuclear (2PN) fertilization rate per injected sibling oocytes was significantly higher after ICSI (group A: 68.2 %±28.8 %; group B: 66.2 %±24.9 %) than after conventional IVF (group A: 41.8 %±32.7 %; group B: 40.1 %±22.1 %), the other variables studied included: the fertilization rates of per allocated sibling oocytes IVF/ICSI, the fertilization rates of sibling oocytes IVF/ICSI after excluding failed IVF fertilization cycles, as well as the cleavage rates of normal fertilization were not statistically significant (P>0.05). Similarly, though the total fertilization failure rate in the IVF group (group A: 42.9 %; group B: 36.4 %) was significantly higher than in the ICSI group (group A: 4.8 %; group B: 0), we did not cancel cycles due to the normal fertilization of sibling oocytes. Embryo transfer was possible in all 32 couples. There were 10 clinical pregnancies in the two groups. We also discovered a possible association between some semen parameters and sperm functions of group A, and women age and duration of infertility of group B and fertilization. It is suggested that adoption of the split IVF/ICSI technology in the above cases may help eliminate fertilization failures. This is also a useful method to investigate the effect of single factor on the employment of assisted reproductive technology.

Untreated Prior Pulmonary Tuberculosis Adversely Affects Pregnancy Outcomes in Infertile Women Undergoing in vitro Fertilization and Embryo Transfer: A Large Retrospective Cohort Study

Objective Prior pulmonary tuberculosis(PTB) on chest X-ray(CXR) was commonly found in infertile patients receiving examinations before in vitro fertilization and embryo transfer(IVF-ET). It was unclear whether untreated PTB would affect pregnancy outcomes after IVF-ET.Method We conducted a retrospective cohort study of 14,254 infertile patients who had received IVFET at Peking University Third Hospital in 2017. Prior PTB was defined as the presence of signs suggestive of old or inactive PTB on CXR, with or without a clinical TB history. Patients who had prior PTB on CXR but had not received a clinical diagnosis and anti-TB therapy were included for analysis. Live birth,clinical pregnancy, and miscarriage rates were compared between the untreated PTB and non-PTB groups.Results The untreated PTB group had significantly lower clinical pregnancy(31.7% vs. 38.1%) and live birth(23.8% vs. 30.6%) rates than the non-PTB group(both P < 0.001). Multivariate analysis revealed that untreated PTB was a risk factor for decreased live birth rate [odds ratio(OR), 0.80;95% confidence interval(CI), 0.66–0.98;P = 0.028] in all patients and for increased miscarriage(OR, 4.19;95% CI,1.69–10.39;P = 0.002) and decreased live birth(OR, 0.45;95% CI, 0.24–0.83;P = 0.011) rates in patients with unexplained infertility.Conclusions Untreated PTB was associated with adverse pregnancy outcomes after IVF-ET, especially in patients with unexplained infertility, highlighting the clinical significance of PTB in this specific patient population.

Reproductive Outcomes in Women with Prior Cesarean Section Undergoing In Vitro Fertilization:A Retrospective Case-control Study

The impact of prior cesarean section（CS） on the pregnancy and neonatal outcomes of in vitro fertilization and embryo transfer（IVF-ET） was investigated. A retrospective analysis was performed on 144 patients with prior CS between January 2013 and December 2015. The pregnancy, delivery, and neonatal outcomes of patients who had previous CS delivery and received IVF-ET were analyzed. The control group comprised 166 patients who had only previous vaginal delivery（VD） and received IVF-ET during the same period. The results showed that the basal follicle stimulating hormone level, estradiol level on human chorionic gonadotropin（h CG） day, gonadotrophin dosage, duration of stimulation, retrieved oocytes, fertilization rate, high-quality embryo rate, multiple birth rate, abortion rate and ectopic pregnancy rate had no significant difference between the two groups（P〉0.05）. The pregnancy rate（40.28% vs. 54.22%） and implantation rate（24.01% vs. 34.67%） were significantly lower（P〈0.05）, and the ratio of embryo difficulty transfer（9/144 vs. 0/166） was significantly higher in CS group than in VD group. The risk of pernicious placenta previa and postpartum hemorrhage in twin deliveries was significantly increased in CS group as compared with that in VD group（P〈0.05）, and gestational age and neonatal birth weight were significantly reduced in twin deliveries as compared with singleton deliveries in both groups（P〈0.05）. It was suggested that the existence of CS scar may impact embryo implantation and clinical pregnancy outcome, and increase the difficulty of ET. We should limit the number of transfer embryos to avoid multiple pregnancies and strengthen gestational supervision in patients with cesarean scar.

Does Lower Dose of Long-acting Triptorelin Maintain Pituitary Suppression and Produce Good Live Birth Rate in Long Down-regulation Protocol for In-vitro Fertilization?

The effects of pituitary suppression with one-third depot of long-acting gonadotropin-releasing hormone（Gn RH） agonist in Gn RH agonist long protocol for in vitro fertilization（IVF）/intracytoplasmic sperm injection（ICSI） were investigated. A retrospective cohort study was performed on 3186 cycles undergoing IVF/ICSI with Gn RH agonist long protocol in a university-affiliated infertility center. The pituitary was suppressed with depot triptorelin of 1.25 mg or 1.875 mg. There was no significant difference in live birth rate between 1.25 mg triptorelin group and 1.875 mg triptorelin group（41.2% vs. 43.7%）. The mean luteinizing hormone（LH） level on follicle-stimulating hormone（FSH） starting day was significantly higher in 1.25 mg triptorelin group. The mean LH level on the day of human chorionic gonadotrophin（h CG） administration was slightly but statistically higher in 1.25 mg triptorelin group. There was no significant difference in the total FSH dose between the two groups. The number of retrieved oocytes was slightly but statistically less in 1.25 mg triptorelin group than in 1.875 mg triptorelin group（12.90±5.82 vs. 13.52±6.97）. There was no significant difference in clinical pregnancy rate between the two groups（50.5% vs. 54.5%）. It was suggested that one-third depot triptorelin can achieve satisfactory pituitary suppression and produce good live birth rates in a long protocol for IVF/ICSI.

Sperm chromatin structure assay results after swim-up are related only to embryo quality but not to fertilization and pregnancy rates following IVF

The aim of this study was to investigate whether the sperm chromatin structure assay （SCSA） results after swim-up are related to fertilization rates, embryo quality and pregnancy rates following in vitrofertilization （IVF）. A total of 223 couples undergoing IVF in our hospital from October 2008 to September 2009 were included in this study. Data on the IVF process and sperm chromatin structure assay results were collected. Fertilization rate, embryo quality and IVF success rates of different DNA fragmentation index （DFI） subgroups and high DNA stainability （HDS） subgroups were compared. There were no significant differences in fertilization rate, clinical pregnancy or delivery rates between the DFI and HDS subgroups. However, the group with abnormal DFI had a lower good embryo rate. So, we concluded that the SCSA variables, either DFI or HDS after swim-up preparation, were not valuable in predicting fertilization failure or pregnancy rate, but an abnormal DFI meant a lower good embryo rate following IVF.

Intramural pregnancy after in vitro fertilization and embryo transfer:A case report

BACKGROUND Intramural pregnancy is a rare type of ectopic pregnancy,which is diagnosed by transvaginal ultrasound and magnetic resonance imaging.Management strategies vary depending on the site of the pregnancy,the gestational age and the desire to maintain fertility.The incidence of intramural pregnancy in assisted reproductive technology is higher than that in natural pregnancy.CASE SUMMARY We present a case of intramural pregnancy after in vitro fertilization and elective single embryo transfer following salpingectomy.The patient was completely asymptomatic and her serumβ-human chorionic gonadotropin level increased from 290 m IU/m L to 1759 m IU/m L.Three-dimensional transvaginal ultrasound indicated a heterogeneous echogenic mass arising from the uterine fundus which was surrounded by myometrium and a slender and extremely hypoechoic area stretching to the uterine cavity which was thought to be a fistulous tract.Therefore,we considered a diagnosis of intramural pregnancy and laparoscopic surgery was conducted at 7 wk gestation.CONCLUSION Early diagnosis and treatment of intramural pregnancy is significant for maintaining fertility.

血清AMH、INHB联合经阴道彩超对IVF-ET助孕患者助孕成功的预测价值

目的:探讨体外受精-胚胎移植(IVF-ET)助孕患者血清中抗苗勒氏管激素(AMH)、抑制素B(INHB)联合经阴道彩超预测患者助孕成功的价值。方法:收集本院2019年1月至2023年1月期间进行IVF-ET助孕的160例患者作为研究对象,根据是否助孕成功将其分为未妊娠组(n=86)和妊娠组(n=74)。比较两组血清AMH、INHB水平和阴道彩超结果;ROC曲线分析血清AMH、INHB联合经阴道彩超对IVF-ET助孕患者助孕成功的预测价值;多因素Logistic回归分析IVF-ET助孕患者助孕成功的影响因素。结果:与妊娠组相比,未妊娠组获卵数、AMH、INHB显著降低(P<0.05)。阴道彩超检查结果显示,未妊娠组子宫内膜厚度显著厚于妊娠组(P<0.05)。ROC曲线显示,AMH、INHB、阴道彩超三者联合预测IVF-ET助孕患者助孕成功的AUC为0.956,敏感性为95.35%,特异性为83.78%,优于AMH、INHB、阴道彩超各自单独预测(Z_(联合检测-AMH)=4.543,Z_(联合检测-INHB)=3.733,Z_(联合检测-子宫内膜厚度)=4.511,均P<0.001)。多因素Logistic回归分析结果显示,获卵数、AMH、INHB、子宫内膜厚度是IVF-ET助孕患者助孕成功的影响因素(P<0.05)。结论:血清AMH、INHB联合经阴道彩超对IVF-ET助孕患者是否成功妊娠具有一定的预测价值。

Post-salpingectomy interstitial heterotopic pregnancy after in vitro fertilization and embryo transfer:A case report

BACKGROUND Heterotopic pregnancy(HP)refers to the coexistence of ectopic pregnancy and intrauterine pregnancy.Salpingectomy is proposed as a pretreatment before in vitro fertilization and embryo transfer(IVF-ET)to reduce the risk of HP.HP after IVF-ET occurs in women who had already underwent bilateral salpingectomy,even though it is extremely rare.CASE SUMMARY A case of a 29-year-old woman with recurrent interstitial HP after IVF-ET following salpingectomy is presented.The main symptom was a sudden and worsening pelvic pain.Physical examinations revealed signs of peritoneal bleeding and irritation with stable vital signs.Transvaginal ultrasound showed a live intrauterine pregnancy and another live embryo with cardiac activity in the left cornu extending beyond the lateral edge of the uterus.Her hemoglobin concentration was 8.0 g/dL,and serum human chorionic gonadotropin value was 171116.9 mIU/mL.With the diagnosis of ruptured HP with internal bleeding,an emergency laparoscopic resection of left cornu was performed.The interstitial pregnancy was removed with caution to protect the intrauterine pregnancy.After the surgical treatment,the intrauterine pregnancy continued with no complications.A healthy baby was delivered by caesarean section at 39 wk.Outcomes of another three cases are further summarized.CONCLUSION Post-salpingectomy HP is a rare but challenging condition.Surgical treatment is preferred in the case with a viable intrauterine pregnancy.

Effects of Ovarian Preservation Time on in vitro Maturation and in vitro Fertilization of Oocytes from Slaughtered Sheep

[Objectives] The aim was to study the effects of ovarian preservation time on in vitro fertilization of oocytes from slaughtered sheep. [Methods] The collected ovaries were randomly and evenly divided into four groups. They were preserved in physiological saline containing penicillin（ 100 IU/ml） and streptomycin（ 100 μg/ml） at 15-20 ℃ for 0（ Control）,6,12 and 18 h,respectively. Then,the oocytes were subjected to in vitro fertilization. [Results]The maturation rates,cleavage rates and blastocyst rates of the oocytes preserved for 6 and 12 h showed no significant differences compared with those of the oocytes preserved for0 h（ 72. 03%,70. 87% vs. 73. 68%; 74. 12%,72. 60% vs. 74. 49%; 22. 22%,20. 75% vs. 23. 29%）（ P 〉 0. 05）. There were also no significant differences in maturation rate,cleavage rate or blastocyst rate between the oocytes preserved for 18 and 0 h（ P 〉 0. 05）. [Conclusions] Within a certain rage（ 0-18 h）,storage time of ovary at 15-20 ℃ does not affect the continued development of oocytes from slaughtered sheep.

In Vitro Fertilization Outcomes Following Assisted Hatching of Embryos with Thick Zona Pellucida—A Prospective Randomized Study

Purpose: Impaired hatching is associated with implantation failure following in vitro fertilization (IVF). Thickening or hardening of the zona pellucida (ZP) has been proposed as a factor in this impairment. We examined whether selective assisted hatching (AH) is beneficial with embryos having a thick ZP. Methods: This prospective, randomized controlled study was performed in the IVF unit of an obstetrics and gynecology department in a university-affiliated hospital. Only patients undergoing IVF and having a ZP thickness of ≥17 μm measured in all their embryos were included. In the intervention group, AH was applied to all embryos, before their transfer. In the control group, embryos were transferred without AH. Implantation, clinical pregnancy and live birth rates were the study endpoints. Results: Both study arms were comparable in most baseline parameters. The two groups did not differ in implantation rates (14.1% control vs. 8.92% intervention, odds ratio (OR) = 0.5974, 95% confidence interval (CI) 0.325 - 1.1), clinical pregnancy rates (36.7% vs. 25.8%, OR = 0.6025, 95% CI 0.274 - 1.325), or live birth rates (25% vs. 18.9%, OR = 0.7021, 95% CI 0.291 - 1.691). Conclusions: Selecting embryos for AH by their ZP thickness as a sole parameter was not found to be beneficial and to improve IVF outcome.