GnRHa用於最終破卵懷孕率胚胎品質仍略低於傳統HCG破卵

Fertil Steril. 2017 Jun;107(6):1323-1328.e2. doi: 10.1016/j.fertnstert.2017.04.014. Epub 2017 May 10.

Reproductive outcomes after a single dose of gonadotropin-releasing hormone agonist compared with human chorionic gonadotropin for the induction of final oocyte maturation in hyper-responder women aged 35-40 years.

Tannus S1, Turki R2, Cohen Y2, Son WY2, Shavit T2, Dahan MH2.

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Abstract

OBJECTIVE:

To investigate the reproductive outcomes after the use of GnRH agonist (GnRHa) compared with hCG for the induction of final oocyte maturation in GnRH antagonist cycles performed in hyper-responder women aged 35-40 years.

DESIGN:

Retrospective study.

SETTING:

Academic fertility center.

PATIENT(S):

Two hundred seventy-two hyper-responder women aged 35-40 years who underwent controlled ovarian stimulation under GnRH antagonist suppression were included. Final oocyte maturation was performed with GnRHa (n = 168) or hCG (n = 104). Embryos were cryopreserved at the blastocyst stage and transferred in subsequent warming cycles (n = 542). Subjects were included in the analysis until live birth was achieved, after which they were excluded from further analysis.

INTERVENTION(S):

None.

MAIN OUTCOME MEASURE(S):

Cumulative live birth rate.

RESULT(S):

Subjects in the GnRHa group achieved a higher number of oocytes (22 vs. 21) and a higher number of mature oocytes (16 vs. 14). The number of cryopreserved blastocysts (median of five blastocysts in both groups) was similar. Women in the hCG group needed a lower number of warming cycles to achieve live birth (1.32 vs. 2.12), had higher embryo implantation rates (48% vs. 39%), and the proportion of embryos transferred until live birth was lower (33% vs. 57%). The cumulative live birth rate was similar between the groups (48.15% vs. 48%).

CONCLUSION(S):

Although the cumulative live birth rate is similar, a single dose of GnRHa possibly results in suboptimal oocyte and embryo competence, as manifested by decreased embryo implantation rates and increased time needed to achieve live birth.

全冷凍之凍胚植入懷孕率明顯高於鮮胚植入(44% vs. 20%)

Fertil Steril. 2017 Jul;108(1):72-77. doi: 10.1016/j.fertnstert.2017.04.020. Epub 2017 Jun 1.

Revisiting the management of recurrent implantation failure through freeze-all policy.

Magdi Y1, El-Damen A2, Fathi AM3, Abdelaziz AM4, Abd-Elfatah Youssef M5, Abd-Allah AA5, Ahmed Elawady M6, Ahmed Ibrahim M4, Edris Y4.

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Abstract

OBJECTIVE:

To determine whether a freeze-all policy for in vitro human blastocysts improves the ongoing pregnancy rate in patients with recurrent implantation failure (RIF).

DESIGN:

Prospective cohort study.

SETTING:

Single private center.

PATIENT(S):

A total of 171 women with RIF divided into two groups: freeze-all policy group (n = 81) and fresh embryo transfer (ET) group (n = 90).

INTERVENTION(S):

Freeze-all policy.

MAIN OUTCOME MEASURE(S):

Ongoing pregnancy rate.

RESULT(S):

The clinical pregnancy rate (52% vs. 28%; odds ratio [OR] 1.86; 95% confidence interval [CI], 1.29-2.68) and ongoing pregnancy rate (44% vs. 20%; OR 2.2; 95% CI, 1.04-3.45) were statistically significantly higher in the freeze-all group than the fresh ET group, respectively. The implantation rate was also statistically significant (freeze-all group 44.2% vs. fresh ET group 15.8%; OR 2.80; 95% CI, 2.00-3.92).

CONCLUSION(S):

The freeze-all policy statistically significantly improved the ongoing pregnancy and implantation rates. Thus, a freeze-all policy is likely to be the new key to helping open the black box of RIF. These findings also are useful for further investigating the adverse effect of controlled ovarian stimulation on in vitro fertilization outcomes.

北歐研究顯示，短期IVF誘導排卵並不會提高乳癌發生率

Fertil Steril. 2017 Jul;108(1):137-144. doi: 10.1016/j.fertnstert.2017.05.010. Epub 2017 Jun 7.

Ovarian stimulation and risk of breast cancer in Swedish women.

Lundberg FE1, Iliadou AN2, Rodriguez-Wallberg K3, Bergh C4, Gemzell-Danielsson K5, Johansson ALV2.

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Abstract

OBJECTIVE:

To investigate whether ovarian stimulation for treating infertility is associated with the risk of breast cancer.

DESIGN:

Nationwide register-based cohort study.

SETTING:

Not applicable.

PATIENT(S):

In a cohort of 1,340,211 women who gave birth 1982-2012, we investigated the relationship between assisted reproductive technology (ART) and incidence of breast cancer. Associations between any ovarian stimulation since 2005 and breast cancer incidence were studied in a separate cohort of 1,877,140 women born 1960-92. Both cohorts were followed through 2012.

INTERVENTION(S):

None.

MAIN OUTCOME MEASURE(S):

Hazard ratios (HRs) and 95% confidence intervals (CIs) for breast cancer.

RESULT(S):

There was no increased risk of breast cancer in women who gave birth after ART compared with women who gave birth after spontaneous conception (adjusted HR, 0.84; 95% CI, 0.74-0.95). The incidence of breast cancer was not increased among women who received controlled ovarian stimulation or among women who received other hormonal fertility treatments since 2005, regardless of live birth (adjusted HR, 0.86; 95% CI, 0.69-1.07; and adjusted HR, 0.79; 95% CI, 0.60-1.05, respectively).

CONCLUSION(S):

No increased incidence of breast cancer was found among women who had gone through ovarian stimulations, including ART. These results are consistent with other studies and reassuring given the widespread and increasing use of ART.

傳統受精方式IVF形成之胚胎仍可準確施行PGD

J Assist Reprod Genet. 2017 Jun 13. doi: 10.1007/s10815-017-0966-7. [Epub ahead of print]

Pre-implantation genetic diagnosis-should we use ICSI for all?

Feldman B1,2,3, Aizer A1, Brengauz M1, Dotan K2, Levron J1,3, Schiff E1,3, Orvieto R4,5,6.

Author information

1

Infertility and IVF Unit, Department of Obstetrics and Gynecology, Sheba Medical Center, Ramat-Gan, Israel.

2

Danek Gertner Institute of Human Genetics, Sheba Medical Center, Ramat-Gan, Israel.

3

Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.

4

Infertility and IVF Unit, Department of Obstetrics and Gynecology, Sheba Medical Center, Ramat-Gan, Israel. raoul.orvieto@sheba.health.gov.il.

5

Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel. raoul.orvieto@sheba.health.gov.il.

6

The Tarnesby-Tarnowski Chair for Family Planning and Fertility Regulation, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel. raoul.orvieto@sheba.health.gov.il.

Abstract

OBJECTIVE:

Intracytoplasmic sperm injection (ICSI) is commonly used during pre-implantation genetic diagnosis (PGD) in vitro fertilization (IVF), aiming to eliminate the risk of contamination from extraneous sperm DNA. Recently, ICSI "overuse" in non-male infertility has been doubted, since it does not offer an advantage over IVF. Prompted by the aforementioned observations, we sought to assess the accuracy of IVF vs ICSI in PGD cases, as might be reflected by a difference in the prevalence of discarded embryos as a consequent of parental contamination.

METHODS:

Cohort-historical study of all consecutive patients admitted to the IVF-PGD program in a large tertiary center. The percentages of complete, incomplete diagnosis, PCR failure, abnormal embryos, and the contamination rate with paternal DNA in the IVF-only and the ICSI-only groups. We reviewed the computerized files of all consecutive women admitted to our IVF for a PGD-PCR cycle. Patients were divided accordingly into three groups: an IVF group-where all the oocytes underwent IVF only, an ICSI group-where all oocytes underwent ICSI, and a mixed group-where sibling oocytes underwent both IVF and ICSI. The laboratory data and the genetic diagnostic results were collected and compared between the different insemination groups.

RESULTS:

Nine-hundred and twenty-seven patients underwent IVF-PGD cycles in our program, 315 in the IVF group, 565 in the ICSI group, and 47 in the mixed group. No differences were observed in fertilization rates, the percentage of embryos available for biopsy, and the percentages of complete, incomplete diagnosis, PCR failure, or abnormal embryos, between the IVF-only and the ICSI-only groups and between the IVF and the ICSI of sibling oocytes in the mixed group. Moreover, contamination with paternal DNA, through contamination with sperm cells, was negligible. Not one single case of misdiagnosis was encountered during the study period.

CONCLUSION:

It might be therefore concluded that IVF should be the preferred insemination methods in PGD cycles, and ICSI should be indicated only in cases of male-factor infertility.

使用新鮮或冷凍精蟲對胚胎形成後分裂速度與品質與囊胚比率無明顯影響

J Assist Reprod Genet. 2017 Jun;34(6):733-740. doi: 10.1007/s10815-017-0928-0. Epub 2017 Apr 29.

Is early embryo development as observed by time-lapse microscopy dependent on whether fresh or frozen sperm was used for ICSI? A cohort study.

Eastick J1,2, Venetis C3,4, Cooke S3, Storr A3,4, Susetio D3, Chapman M3,4.

Author information

Abstract

PURPOSE:

The aim of this study was to compare timings of key events of embryo development from those originating from either fresh or cryopreserved ejaculate sperm using time-lapse technology.

METHODS:

In this retrospective observational cohort study, time-lapse technology was used to monitor 1927 embryos from 234 women undergoing intracytoplasmic sperm injection (ICSI) and utilizing either fresh (n = 172 cycles) or cryopreserved ejaculate sperm (n = 62 cycles) for insemination were included in the study. Key developmental events as described in time-lapse were compared with the use of generalized estimating equations (GEE) to adjust for any auto-correlation between the observations. In addition, multivariable logit regression models were used to account for any known baseline differences between the two groups.

RESULTS:

There were no differences in conventional embryo development such as number of 8-cell embryos by 72 h (p = 0.359), the number of blastocysts by 120 h (p = 0.417), and the number of top quality blastocysts (p = 0.956) between the two groups compared. There were no statistical differences in the timings of any of the key embryo developmental events (PN_t1, NEBD, cytokinesis, t2, t3, t4, t5, t6, t7, t8, tM, tSB, tEB, tHB, s1, s2, s3, cc2, and cc3) when either fresh or cryopreserved ejaculate sperm was used for ICSI. This was also confirmed with conventional morphological assessment.

CONCLUSIONS:

This observational cohort study has shown that there are no differences in the morphokinetic parameters of early embryo development when either fresh or frozen ejaculate sperm are used for ICSI insemination.

囊胚期胚胎破殼ZP靠近ICM或遠離ICM之機率各占一半

J Assist Reprod Genet. 2017 Jun;34(6):725-731. doi: 10.1007/s10815-017-0933-3. Epub 2017 May 3.

The bovine embryo hatches from the zona pellucida through either the embryonic or abembryonic pole.

Negrón-Pérez VM1, Hansen PJ2.

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Abstract

PURPOSE:

Implantation of the mammalian embryo in the uterus is preceded by escape from the zona pellucida. In some species, hatching from the zona occurs preferentially from one or the other poles of the embryo. The situation for the bovine embryo, in which hatching precedes attachment to the uterus by more than a week, is unclear. The purpose was to describe whether hatching of the bovine embryo from the zona pellucida occurs preferentially from the embryonic or abembryonic pole.

METHODS:

Bovine blastocysts undergoing hatching were examined by light microscopy (n = 84) and epifluorescence imaging using antibodies for markers of epiblast, hypoblast, and trophectoderm (TE) (n = 26). The location of hatching was classified as being at the embryonic pole, if hatching occurred ipsilateral to the inner cell mass (ICM), or abembryonic, if hatching occurred contralateral to the ICM.

RESULTS:

A total of 55% of blastocysts exited the zona pellucida through an opening at the embryonic pole. In these cases, 68% of the cells emerging through the zona pellucida were derived from the ICM. The remainder of blastocysts hatched from an opening either contralateral or to the side of the ICM. In these cases, 87% of hatched cells were TE.

CONCLUSION:

For the bovine embryo, there is nearly equal probability of hatching from the embryonic or abembryonic poles. Given that the surface area of the zona pellucida in contact with the TE overlying the ICM is less than for the remainder of the blastocyst, there is some preference for hatching through the embryonic pole. Thus, the bovine embryo is distinct from the mouse and human, where hatching occurs preferentially at the abembryonic pole.

優質胚胎須在授精
26h內完成第一次分裂,
38h內完成第二次分裂,
80h內完成胚葉融合，
96h內完成囊胚腔形成

J Assist Reprod Genet. 2017 Jun 1. doi: 10.1007/s10815-017-0962-y. [Epub ahead of print]

Selection of human blastocysts with a high implantation potential based on timely compaction.

Mizobe Y1,2, Ezono Y3, Tokunaga M3, Oya N3, Iwakiri R3, Yoshida N3, Sato Y3, Onoue N3, Miyoshi K4.

Author information

Abstract

PURPOSE:

Recently, we established a noninvasive system for selecting human blastocysts with a high pre-transfer implantation potential based on first and second division patterns. The present study was carried out to improve the selection system.

METHODS:

Embryos that completed first and second divisions within 25.90 and 37.88 h after culture, respectively, were selected using a time-lapse incubator. We examined the effects of compaction and blastocyst formation times on pregnancy rates after transferring these embryos at the blastocyst stage.

RESULTS:

The completion of compaction and blastocyst formation times (79.93 and 97.47 h after culture, respectively) of embryos resulting in pregnancies after transfer were significantly (P < 0.01) shorter than those (86.46 and 100.34 h after culture, respectively) of embryos that failed to induce pregnancies. Embryo selection based on completion of compaction time improved pregnancy rates (40.9 vs. 74.6%, P < 0.01).

CONCLUSIONS:

Of the embryos that formed two cells during the first division within 25.90 h after culture and four cells during the second division within 37.88 h after culture, those that completed compaction within 79.93 h after culture before reaching the blastocyst stage had a high implantation potential.

單一病例報告顯示染色體鑲嵌化(chr 13,21)之胚胎植入後仍可能產出染色體正常寶寶

J Assist Reprod Genet. 2017 Jun 24. doi: 10.1007/s10815-017-0974-7. [Epub ahead of print]

Mosaic embryo transfer after oocyte in vitro maturation in combination with non-invasive prenatal testing (NIPT)-first report of a euploid live birth.

Inoue N1, Lopez R2, Delgado A3, Nuñez D1, Portella J1, Noriega-Hoces L1,3, Guzmán L4,5.

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Abstract

PURPOSES:

The purpose of this study is to describe a healthy life birth after a mosaic embryo transfer in oocyte in vitro maturation (IVM).

METHODS:

Patient received minimal stimulation, starting on day 3 after menstrual period. No hCG trigger was administered. Oocyte retrieval was performed and oocytes were matured for 30 h. After denuding, mature oocytes were inseminated by ICSI. Embryos were cultured until blastocyst stage and biopsied.

RESULTS:

One euploid embryo after array comprehensive genome hybridization (aCGH) was diagnostic. However, the next-generation sequencing (NGS) re-analysis showed that embryo was a mosaic for chromosome 13 and 21. Nevertheless, pregnancy ultrasound scans and non-invasive prenatal test (NIPT-Verifi-Illumina) indicated a normal fetus development. Finally, a healthy baby was born after 38 weeks. Its weight was 4480 g, head circumference 36 cm, and total length of 51 cm. To confirm that the baby was chromosomically normal, an NGS test was performed in buccal cells, a normal profile was obtained.

CONCLUSIONS:

Our finding confirmed that mosaic embryo transfer would bring a healthy offspring.

子宮內膜異位瘤之硬化治療: 不孕病患保留卵巢功能之替代療法
注射酒精入異位瘤內並部分酒精滯留於異位瘤內可達較低復發率

Fertil Steril. 2017 Jul;108(1):117-124.e5. doi: 10.1016/j.fertnstert.2017.05.015. Epub 2017 Jun 1.

Sclerotherapy in the management of ovarian endometrioma: systematic review and meta-analysis.

Cohen A1, Almog B2, Tulandi T3.

Author information

Abstract

OBJECTIVE:

To evaluate the efficacy of sclerotherapy for ovarian endometrioma on the risk of recurrence, clinical symptoms, and reproductive function.

DESIGN:

Systematic review and meta-analysis.

SETTING:

Not applicable.

PATIENT(S):

Patients who underwent sclerotherapy of ovarian endometrioma.

INTERVENTION(S):

An electronic-based search with the use of Pubmed, Embase, Ovid Medline, Google Scholar, Clinicaltrials.gov, and the Cochrane Central Register of Controlled Trials.

MAIN OUTCOME MEASURE(S):

Recurrence rate, symptoms relief, fertility outcome, and adverse events.

RESULT(S):

Eighteen studies were included in our review. The overall recurrence rates of endometrioma after sclerotherapy ranged from 0 to 62.5%. The risk of recurrence was significantly higher in women who were treated by means of ethanol washing than by means of ethanol retention. The number of oocytes retrieved was higher after endometrioma sclerotherapy compared with laparoscopic cystectomy, but clinical pregnancy rates were similar. There was no difference in the number of oocytes retrieved and the clinical pregnancy rates between the sclerotherapy-treated group with and the untreated group.

CONCLUSION(S):

Sclerotherapy for ovarian endometrioma may be considered in symptomatic women who plan to conceive.

子宮內膜異位之卵子形成之胚胎基因異常率並不明顯提高

Fertil Steril. 2017 Jun 23. pii: S0015-0282(17)30421-1. doi: 10.1016/j.fertnstert.2017.05.038. [Epub ahead of print]

Patients with endometriosis have aneuploidy rates equivalent to their age-matched peers in the in vitro fertilization population.

Juneau C1, Kraus E2, Werner M3, Franasiak J4, Morin S4, Patounakis G5, Molinaro T3, de Ziegler D6, Scott RT4.

Author information

Abstract

OBJECTIVE:

To determine whether endometriosis ultimately results in an increased risk of embryonic aneuploidy.

DESIGN:

Retrospective cohort.

SETTING:

Infertility clinic.

PATIENT(S):

Patients participating in an in vitro fertilization (IVF) cycle from 2009-2015 using preimplantation genetic screening (PGS) who had endometriosis identified by surgical diagnosis or by ultrasound findings consistent with a persistent space-occupying disease whose sonographic appearance was consistent with endometriosis.

INTERVENTION(S):

None.

MAIN OUTCOME MEASURE(S):

Rate of aneuploidy in endometriosis patients undergoing IVF compared to controls without endometriosis undergoing IVF.

RESULT(S):

There were 305 patients with endometriosis who produced 1,880 blastocysts that met the criteria for inclusion in the endometriosis group. The mean age of the patients with endometriosis was 36.1 ± 3.9 years. When the aneuploidy rates in patients with endometriosis and aneuploidy rates in patients without endometriosis were stratified by Society for Assisted Reproductive Technology age groups and compared, there were no statistically significant differences in the rate of aneuploidy (odds ratio 0.85; 95% confidence interval, 0.84-0.85).

CONCLUSION(S):

Patients with endometriosis undergoing IVF have aneuploidy rates equivalent to their age-matched peers in IVF population who do not have endometriosis.

乾式培養箱(vs傳統濕式培養箱)對於胚胎品質與懷孕率有不利影響

Fertil Steril. 2017 Jun 23. pii: S0015-0282(17)30419-3. doi: 10.1016/j.fertnstert.2017.05.036. [Epub ahead of print]

Humid versus dry incubator: a prospective, randomized, controlled trial.

Fawzy M1, AbdelRahman MY2, Zidan MH3, Abdel Hafez FF4, Abdelghafar H2, Al-Inany H5, Bedaiwy MA6.

Author information

Abstract

OBJECTIVE:

To evaluate the efficacy of a dry versus humidified incubator on human embryo development ex vivo.

DESIGN:

Prospective, double-blind, randomized, controlled trial.

SETTING:

Private fertility centers.

PATIENT(S):

A total of 297 women undergoing in vitro fertilization randomized into two groups.

INTERVENTION(S):

From days 0 to day 5 or 6 of culture, intervention group embryos exposed to dry culture and control group embryos exposed to humidified culture.

MAIN OUTCOME MEASURE(S):

Subsequent ongoing pregnancy rate.

RESULT(S):

After transfer of embryos, there were statistically significantly lower rates of clinical and ongoing pregnancy in the dry culture arm than in the humidified culture arm (odds ratio [OR] 0.57; 95% confidence interval [CI], 0.36-0.91; versus OR 0.54; 95% CI, 0.34-0.85). On day 3 of culture, embryo quality and compaction were lower in the dry culture group (OR 0.38; 95% CI, 0.32-0.45) than in the group exposed to humidified culture (OR 0.23; 95% CI, 0.19-0.27). On day 5 of culture, embryos in dry culture had a lower rate of blastocyst formation (OR 0.39; 95% CI, 0.33-0.46), quality (OR 0.34; 95% CI, 0.29-0.40), and cryopreservation (OR 0.41; 95% CI, 0.35-0.48).

CONCLUSION(S):

In this study, human embryos cultivated ex vivo in a dry incubator had statistically significantly decreased implantation and clinical and ongoing pregnancy rates. Our findings indicate the need for larger multicenter, randomized, controlled trials.

添加 glutathione (GSH)可提高原始卵子冷凍解凍後形成胚胎之著床率

Cryobiology. 2017 Jun;76:98-103. doi: 10.1016/j.cryobiol.2017.04.002. Epub 2017 Apr 12.

Beneficial effects of glutathione supplementation during vitrification of mouse oocytes at the germinal vesicle stage on their preimplantation development following maturation and fertilization in vitro.

Moawad AR1, Tan SL2, Taketo T3.

Author information

Abstract

Oocyte cryopreservation is imperative for assisted reproductive technologies (ART). Although cryopreservation of oocytes at the Metaphase II has been widely used, immature oocytes at the germinal vesicle stage (GV-oocytes) need to be cryopreserved in certain situations such as cancer patients; however, the success rate of embryonic development from the GV-oocytes remains low largely due to the requirement for in vitro maturation (IVM). Our aim was to investigate the effects of glutathione (GSH) supplementation during vitrification and warming of mouse GV-oocytes on the preservation of developmental competence. GV-oocytes within cumulus oocyte complexes (COCs) were collected from C57BL/6J (B6) and (B6.DBA)F1 mouse strains and subjected to vitrification and warming, followed by IVM. The vitrification, warming or IVM medium was supplemented with GSH at 0-4.0 mM. In vitro matured oocytes were then fertilized in vitro and cultured in KSOMaa up to 4 days. The first cleavage and blastocyst development were evaluated morphologically, and their rates were statistically analysed by one-way ANOVA followed by Tukey's multiple comparisons test. The difference was considered significant at P < 0.05. The results showed that GSH supplementation in the IVM medium exhibited no or rather inhibitory effects on the first cleavage or blastocyst development in both mouse strains except that 1.0 mM GSH increased the blastocyst development rate in B6. By contrast, 1 mM GSH supplementation during vitrification and warming increased the blastocyst development rate in both mouse strains, more efficiently in B6 than (B6.DBA)F1. In conclusion, GSH supplementation during vitrification and warming of GV-oocytes protects the oocytes from freezing-inflicted loss of developmental competence.

dry ice 乾冰可取代液態氮用於短期冷凍儲存輸送冷凍精子

Theriogenology. 2017 Jul 1;96:49-57. doi: 10.1016/j.theriogenology.2017.04.003. Epub 2017 Apr 3.

Dry ice is a reliable substrate for the distribution of frozen mouse spermatozoa: A multi-centric study.

Raspa M1, Guan M2, Paoletti R3, Montoliu L4, Ayadi A5, Marschall S6; EMMA/Infrafrontier Technical Working Group, Fray M2, Scavizzi F7.

Author information

Abstract

Disseminating mouse stocks as frozen materials offers both ethical and logistical advantages over live animal shipment, minimizing the welfare issues and avoiding some of the complex custom regulations that are associated with live animal transportation. Embryo freezing in liquid nitrogen (LN2) at -196 °C has traditionally been the method of choice for archiving mouse lines. However, spermatozoa freezing is emerging as a more convenient alternative due to the application of innovative cryopreservation and recovery protocols. In addition, frozen spermatozoa are less sensitive to post-freezing temperature fluctuations. Here we demonstrated that spermatozoa frozen using standard laboratory protocols can be safely stored in dry ice (-79 °C) for at least seven days. The protocol we report here is robust and has been validated in a multi-centric study involving mouse spermatozoa samples exchanged between five European Mouse Mutant Archive (EMMA) nodes. Furthermore, following shipment on dry ice the spermatozoa can be returned to LN2 for long term storage without any noticeable detrimental effect. This protocol permits frozen spermatozoa to be shared and shipped in dry ice between biorepositories, networks and scientific institutions at low cost, using common courier companies, while avoiding the complexities, risks and hazards associated with using a traditional LN2 dry-shipper.