Human uterine transplantation: a review of outcomes from the first 45 cases

Hypothermic machine perfusion in uterus transplantation in a porcine model: A proof of concept and the first results in graft preservation

INTRODUCTION

Graft optimization is a necessity in order to develop uterus transplantation from brain-dead donors, as a complement to living donors, as these grafts are rare and the last organs retrieved in multiple organ donation. The aim of this study was to assess the feasibility and interest of hypothermic machine perfusion (HMP) in uterus transplantation using a porcine model; secondary outcomes were the evaluation of the graft's tolerance to a prolonged cold ischaemia time and to find new biomarkers of uterus viability.

MATERIAL AND METHODS

Fifteen uterus allotransplantations were performed in a porcine model, after 18 h of cold ischaemia, divided in three groups: Static cold storage in a HTK solution, HMP (with the VitaSmart (™) machine Bridge to Life Ltd.) with a UW-MP solution, and static cold storage in a UW solution. The main outcome was macroscopic: uterine arteries pulsatility, recoloration, and bleeding at the cut. Secondary outcomes were histological analyses (Zitkute and inflammation scores), caspase3 immunohistochemistry and plasmatic dosage of biomarkers.

RESULTS

14/15 allotransplantations were performed according to the protocol and met the criteria of macroscopic vitality. Grafts treated with HMP (MP did not show significantly more tissue) damage than the recipient's uterus, contrary to grafts in static cold storage, independently of the solution used. This difference disappeared one and 3 h after uterus transplantation. Plasma dosages before and after uterus transplantation did not allow to identify a new biomarker of uterus viability.

CONCLUSIONS

HMP is feasible in a porcine model, without inflicting damage on the grafts during cold ischaemia time. Grafts exposed to HMP seemed to better endure reperfusion phenomena, but this advantage did not last over time.

How do women with Rokitansky syndrome and healthcare professionals reflect on the provision of uterine transplantation? Insights from an interview study in France, Norway, and Sweden

INTRODUCTION

Uterine transplantation is currently intended for women with absolute uterine infertility. Since proof of the concept in 2014, many countries have started research programs and clinical activities. However, access to uterine transplantation remains limited given that only a few hundred transplants have been described worldwide compared with the 1.5 million women of childbearing age who suffer from absolute uterine infertility. The aim of this study was to investigate how limited access to uterine transplantation is perceived by women with Mayer-Rokitansky-Küster-Hauser syndrome and health professionals involved in uterus transplantation programs.

MATERIAL AND METHODS

We conducted a qualitative study with semistructured interviews in France, Norway, and Sweden with women with Mayer-Rokitansky-Küster-Hauser syndrome and health professional involved in uterine transplantation programs. The interviews were analyzed manually using thematic content analysis. The research questions were: How do (a) women with Mayer-Rokitansky-Küster-Hauser syndrome and (b) healthcare professionals involved in uterus transplantation programs perceive uterus transplantation and its accessibility 10 years after proof of concept?

RESULTS

The interviews enabled us to highlight a number of themes addressed by doctors and women with Mayer-Rokitansky-Küster-Hauser syndrome, the main ones being the hope raised by this technique and the disappointment for those who do not have access to it, the lack of perception of the risks associated with the technique, and finally, an inequity of access and the training difficulties this entails for the teams.

CONCLUSIONS

Access to uterine transplantation varies widely across Europe owing to legislative restrictions and limited access due to resources or competence. The result is a feeling of injustice/misunderstanding and despair for these women who had planned to become parents and cannot benefit from a transplant. They appear to be poorly supported. Women who are ultimately unable to access a transplant program should perhaps be given psychological support to deal with this disappointment, whereas the minority who finally have had access to transplant programs are supervised by well-trained multidisciplinary teams.

Uterus transplantation: A scoping review focused on obstetric outcomes

BACKGROUND

Congenital uterine anomalies include a wide diversity of uterine malformations that can compromise reproductive potential. Uterus transplantation (UTx) proposes an innovative treatment for absolute uterine factor infertility; however, there is a lack of standardized protocols to guide clinical management among this population.

OBJECTIVES

To describe recipient and donor characteristics and obstetric outcomes in patients undergoing UTx.

SEARCH STRATEGY

We performed a literature search using the PubMed database to retrieve available scientific articles. We analyzed the references of included articles to assess additional articles that could be eligible to be included in the review. Likewise, we identified further studies using other methods, including Google Scholar.

SELECTION CRITERIA

Titles and abstracts were screened in duplicate to select original reports with information available for the outcomes of interest.

DATA COLLECTION AND ANALYSIS

This review assessed the advantages and disadvantages of the techniques used, patient characteristics, obstetric and non-obstetric complications, functional duration of the organ, and neonatal outcomes.

MAIN RESULTS

Among the 36 reports included in this review we found 55 pregnancies and 38 live births following UTx and a higher success rate for in vivo uterine donations. The most common obstetric complications reported included miscarriage, pre-eclampsia, and gestational hypertension. The most common non-obstetric complications reported include episodes of rejection, acute kidney injury, anemia, and cholestasis. Living donors required a comprehensive preoperative workup, decreasing organ rejection, infection, and vascular complications.

CONCLUSIONS

More studies are needed to standardize the UTx procedure and improve obstetric, fetal, and neonatal outcomes. Further understanding of which recipient and donor characteristics minimize complications will significantly decrease the risk of adverse outcomes.

Uterus transplantation: A bibliometric review of six-decade study from 1960 to 2024

INTRODUCTION

Some women are unable to become pregnant because they do not have a functional uterus. Over the last decade, it has become possible for these women to get pregnant through uterus transplantation, which has been the subject of numerous research studies. Therefore, the purpose of this study is to review published articles in the uterus transplantation area.

MATERIAL AND METHODS

We conducted a cross-sectional bibliometric review to study the 100 highly cited papers in the Web of Science and Scopus databases from 1960 to 2024. Our research applied bibliometric analysis to these top 100 highly cited papers. Document citation and co-occurrence analysis were used for the data study. VOSviewer along with Bibliometrix® software was used to design the maps.

RESULTS

The trend of uterus transplantation publications increased exponentially after 2010. Sweden is the leading country, followed by the USA and Spain. Fertility and Sterility, Lancet, American Journal of Transplantation, and Human Reproduction were the highly cited journals. Collaboration among countries showed that the most collaboration took place between Sweden and Spain (18), Sweden and the USA (14), the USA and Spain (8), Sweden and Australia (6), and the USA and the United Kingdom (6). Furthermore, the results found that more than one-third of the highly cited papers were review papers (39%) and 27% were clinical trial studies.

CONCLUSIONS

This bibliometric review provides a valuable contribution to the literature on uterine transplantation by synthesizing and analyzing existing research findings. It offers insights into current trends, key themes, geographic distribution, and potential areas for future research within this rapidly evolving field.

Inhibition of NFAT promotes loss of tissue resident uterine natural killer cells and attendant pregnancy complications in humans

Uterine natural killer cells (uNKs) are a tissue resident lymphocyte population that are critical for pregnancy success. Although mouse models have demonstrated that NK deficiency results in abnormal placentation and poor pregnancy outcomes, the generalizability of this knowledge to humans remains unclear. Here we identify uterus transplant (UTx) recipients as a human population with reduced uNK cells and altered pregnancy phenotypes. We show that the NK reduction in UTx correlates with impaired transcriptional programming of NK tissue residency arising from the inhibition of NFAT-mediated signaling. Our observations suggest that NFAT-dependent genes modulate multiple molecular tissue residency programs in uNKs. These include early residency programs involving AP-1-family transcription factors and TGF-β-mediated upregulation of surface integrins. Collectively, our data identify a previously undescribed role for NFAT in uterine NK tissue residency and provide novel mechanistic insights into the biologic basis of pregnancy complications due to alteration of tissue resident NK subsets in humans.

One Sentence Summary

Role of NFAT in uterine NK cell tissue residency.

Optimizing care for MRKH patients: From malformation screening to uterus transplantation eligibility

INTRODUCTION

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome with utero-vaginal aplasia is the most severe form of the Müllerian duct anomalies and can be associated with extra-genital abnormalities such as renal or skeletal anomalies, hearing loss, or cardiac defects. The past two decades have witnessed significant advances both in understanding the etiologies of MRKH and in the development of fertility treatments such as uterine transplantation. The present work aimed to determine the rate of women with MRKH syndrome who underwent optimal initial management (after comprehensive malformation assessment) and to establish the rate of patients eligible for uterine transplantation (i.e., those with a vaginal length ≥7 cm without reconstruction using a bowel segment, and an anti-Müllerian hormone level >1.5 ng/mL before 35 years).

MATERIAL AND METHODS

Cohort study of 85 women with MRKH syndrome consulting in our tertiary center.

RESULTS

62.4% of women with MRKH syndrome had an exhaustive malformative evaluation according to the French guidelines (Protocole National de Diagnostic et de Soin [PNDS]), of which 76.5% had associated malformations (MRKH type II). Pedigree, when available, showed a family history of infertility or a urogenital tract spectrum anomaly in 60% of cases. Concerning the uterine transplantation selection criteria, when evaluated, 22.6% of women had an anti-Müllerian hormone level <1.5 ng/mL and 36% a vaginal length <7 cm. On the 21 women with complete evaluation of both primary and secondary outcomes, 14 of them would be eligible for a uterine transplantation program at the time of consultation according to the main inclusion criteria of uterine transplantation program.

CONCLUSIONS

Women with MRKH syndrome are often inadequately explored for associated malformations. Early assessment and monitoring of the ovarian reserve is key for fertility preservation, especially in the era of uterine transplantation.

Egg donation and gestational surrogacy: Pregnancy is riskier with an unrelated embryo

Modern medicine has revolutionized family planning. Remarkably, women1 can carry to term embryos with whom they share no genetic connection, a feat made possible through egg donation and/or gestational surrogacy. Our reproductive systems evolved to accommodate embryos that are 50% related to the carrier, not 0% related. Here, we apply evolutionary theory to explain how and why pregnancy is riskier with an unrelated embryo. When a woman gestates an unrelated embryo, she is significantly more likely to develop preeclampsia and other diseases above and beyond the known risks associated with advanced maternal age, IVF, multiple gestation, and subfertility. Such "allogeneic pregnancies" are riskier even in fertile, healthy, commercial surrogates and when the egg is donated by a young, healthy donor. We propose that unrelated embryos present a special immune challenge to the gestational carrier, because they have fewer matching genes to the maternal body-therefore exacerbating symptoms of evolutionary maternal-fetal conflict. Indeed, maternal risks seem lower when the embryo is more related to the carrier, e.g., if a sister donates the egg. Finally, we discuss microchimerism in egg donation pregnancies, whereby wholly foreign cells pass from mother to embryo and vice-versa. We conclude with several medical proposals. First, egg donors and surrogates should be informed of the increased health risks they would face. In considerations of risk, these young, fertile women should not be compared to older, infertile women undergoing IVF; the proper comparison group is other young, fertile women. Second, contrary to some medical advice, perhaps genetically-related egg donors and surrogates should be preferred, all else equal. An immunological matching scheme, like what is used for organ transplants, could improve surrogate pregnancy outcomes. Third, more research is needed on microchimerism, sperm exposure, and the long-term impacts of allogeneic pregnancies on maternal and child health.

Uterus transplantation: a rescue technique to save the viability and functionality of the graft after intra-operative outflow thrombosis

Objective

To study a surgical approach to venous vascular thrombosis after uterus transplantation (UTx). Uterus transplantation is the only treatment for uterine factor infertility when conventional therapies are not possible. One of the major limitations of UTx is the high incidence of vascular thrombosis, which in most series reaches approximately 20%.

Design

A case report.

Setting

Hospital.

Patients

We report here a technique used in a 30-year-old woman with congenital absence of the uterus who developed intraoperative thrombosis after a UTx from a brain-dead donor.

Intervention

The UTx was performed by revascularizing the graft through bilateral donor internal iliac vessels (artery and vein) anastomosed end-to-side to the external iliac vessels of the recipient. The superior uterine veins were not anastomosed and were left unreconstructed. An end-to-end graft to the recipient's vaginal anastomosis was performed. After uterus reperfusion, congestion of the organ was noted, and bilateral venous thrombosis of the internal iliac veins of the graft was found. A "Y-shaped" venous jump graft was used to restore venous outflow of the left superior uterine vein and the internal iliac vein of the graft after thrombectomy.

Main Outcome Measures

Viability and functionality of the uterus graft after intraoperative bilateral venous thrombosis.

Results

The postoperative course was uneventful, and this UTx resulted in the delivery of a healthy infant.

Conclusion

To our knowledge, this is the first successful rescue technique used to restore venous outflow and save the viability and functionality of a transplanted uterus. We demonstrated that a transplanted uterus from a deceased donor with a monolateral outflow could succeed in pregnancy and the delivery of a healthy infant.

Endometrium procurement and transplantation restores fertility in rats

RESEARCH QUESTION

Can rat endometrium be successfully procured and transplanted, and can a similar method be used to procure human endometrium?

DESIGN

Rat endometrium was procured using an endometrium stripping method and transplanted into female Sprague-Dawley rats. Macroscopic and histological changes, endometrial receptivity-related protein concentrations and fertility were assessed. Additionally, a preliminary experiment was conducted to procure human endometrium using a similar method.

RESULTS

Endometrium was successfully procured from both rats and humans, which contained intact endometrium and parts of the adjacent inner annulus myometrium. Endometrium auto-transplantation was conducted in rats and the procedure lasted a total of 41.3 ± 5.7 min with a mean blood loss of 0.09 ± 0.04 g. The transplanted endometrium survived well, but a fibrotic zone formed between the transplant and recipient tissue. Compared with sham rats, those with endometrium transplantation had similar endometrial thickness and endometrial gland numbers but reduced vascular density at 8 weeks after surgery. Endometrium transplantation also retained expression of the endometrial receptivity-related proteins leukaemia inhibitory factor and vascular endothelial growth factor. In contrast to non-pregnancy in the stripped horn, a mean of 5.0 ± 2.7 fetuses developed in the transplanted horn, and full-term live fetuses were conceived in the horns with transplanted endometrium.

CONCLUSIONS

Endometrium procurement by stripping method can obtain an intact and functional endometrium, and endometrium transplantation can reconstruct the uterine cavity and restore fertility in rats.

Living-Donor Uterus Transplantation: A Clinical Review

Uterus transplantation (UTx) is currently the only available treatment for absolute uterine factor infertility. More than 90 uterus transplantations have been performed worldwide, mostly from living donors. Living-donor (LD) UTx is a challenging surgical procedure since it poses ethical issues, and it is a high-risk and invasive surgery with higher hysterectomy-related risks compared to conventional hysterectomy. A total of 59 living-donor hysterectomies have been reported in the literature, including 35 performed with a laparotomic approach, 20 with a robotic approach and 4 with a laparoscopic approach. The mean donor age was 45.6 ± 9.1 years, and 22 were unrelated with the recipients, 34 were emotionally related (27 mothers, 5 sisters, 2 mother's sisters). The mean recipient age was 28.8 ± 4.5 years. Mayer-Rokitansky-Küster-Hauser syndrome was the most common indication for uterus transplant. Robotic living-donor hysterectomy had the longest operative time but resulted in a lower blood loss and postoperative stay compared to laparotomic and laparoscopic approaches. Twenty-nine births from LD-UTx have been reported, four after robotic living-donor hysterectomy and twenty-five after a laparotomic procedure. UTx is now an effective treatment for women with UFI. While living-donor UTx in some cases may be considered an experimental procedure, it offers the extraordinary possibility to give women the opportunity to have a pregnancy. Many efforts should be made to reduce the potential risks for donors, including the use of mini-invasive techniques, and the efficacy of UTx in the recipients, giving the potential harm of immunosuppression in a recipient of a non-life-saving organ.

The Current Trend of Fertility Preservation in Patients with Cervical Cancer

Although the incidence of most cancers increases with age, a considerable number of patients receive a diagnosis of cancer during their reproductive years. Young women wishing to get pregnant after cancer treatment should be provided consultation for fertility preservation and possible options. In patients with cervical cancer, hysterectomy is often inevitable because the uterus is located too close to the cervix. For young patients with cervical cancer who desire to get pregnant and whose lesion is confined to the cervix, sparing the uterus and, partially, the cervix should be prioritized as much as possible, while simultaneously ensuring favorable oncologic outcomes. In this review, we explore how to choose an adequate fertility-preserving procedure to achieve a balance between favorable oncologic outcomes and fertility and management during pregnancy after a radical trachelectomy in women with early-stage cervical cancer. For patients who require hysterectomy or radiation, evaluation of the ovarian condition and laparoscopic ovarian transposition followed by the use of artificial reproduction techniques and pregnancy by surrogacy should be discussed as options to achieve a successful pregnancy.

Molecular Basis of Müllerian Agenesis Causing Congenital Uterine Factor Infertility-A Systematic Review

Infertility affects around 1 in 5 couples in the world. Congenital absence of the uterus results in absolute infertility in females. Müllerian agenesis is the nondevelopment of the uterus. Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a condition of uterovaginal agenesis in the presence of normal ovaries and the 46 XX Karyotype. With advancements in reproductive techniques, women with MA having biological offspring is possible. The exact etiology of MA is unknown, although several genes and mechanisms affect the development of Müllerian ducts. Through this systematic review of the available literature, we searched for the genetic basis of MA. The aims included identification of the genes, chromosomal locations, changes responsible for MA, and fertility options, in order to offer proper management and counseling to these women with MA. A total of 85 studies were identified through searches. Most of the studies identified multiple genes at various locations, although the commonest involved chromosomes 1, 17, and 22. There is also conflicting evidence of the involvement of various candidate genes in the studies. The etiology of MA seems to be multifactorial and complex, involving multiple genes and mechanisms including various mutations and mosaicism.

INvestigational Study Into Transplantation of the Uterus (INSITU): a cross-sectional survey among women with uterine factor infertility in the UK assessing background, motivations and suitability

IMPORTANCE

The study summarises the selection prescreen criteria currently used in the UK for a uterus transplant and highlights the number of women who are suitable to proceed.

OBJECTIVES

To assess the demographics, motivations, reasons and suitability among women with absolute uterine factor infertility (AUFI) to undergo uterine transplantation (UTx).

DESIGN

A cross-sectional survey.

SETTING

An electronic questionnaire was sent via email to women with AUFI who had previously been referred to the UTx research team or approached the Womb Transplant UK Charity. The questions assessed suitability to undergo UTx based on demographic information, perceptions to adoption and surrogacy and reasons why UTx was preferable. Responses were assessed against the study selection criteria.

PARTICIPANTS

Women with AUFI.

RESULTS

210 women completed the questionnaire. The most common aetiology of AUFI in our cohort was Mayer-Rokitansky-Küster-Hauser (68%; n=143) whereas 29% (n=62) had previously undergone hysterectomy. 63% (n=132) of the cohort had previously considered adoption, 5% (n=11) had attempted it and 2 (1%) had successfully adopted. The most common reason cited to undergo UTx over adoption was to experience gestation (n=63; 53%), while 37% (n=44) wanted a biologically related child. 76% (n=160) of participants had previously considered surrogacy, 22 (10%) had attempted it and 2 (1%) had successfully become mothers using a surrogate. The most common reason to undergo UTx over surrogacy was to experience gestation (n=77; 54%). 15% (n=21) were concerned about the legal implications, 14% (n=20) identified the financial cost as a barrier and 8% (n=12) could not consider it due to religious reasons. On adhering to the selection criteria, 65 (31%) women were suitable to proceed with the trial.

CONCLUSION

The study demonstrates that implementing commonly used selection criteria for a UTx led to an attrition rate of more than two-thirds of women who requested to initially undergo the process. As more studies present outcomes following UTx, critical assessment of the selection criteria currently used is warranted to ensure potential recipients are not being unnecessarily excluded.

TRIAL REGISTRATION NUMBER

NCT02388802.

Mayer-Rokitansky-Küster-Hauser syndrome patients' interest, expectations and demands concerning uterus transplantation

OBJECTIVE

To better understand patients' conditions and expectations before starting a uterus transplantation (UTx) program for women suffering from Mayer-Rokitansky-Küster-Hauser syndrome (MRKH syndrome).

METHOD

A web-based survey was conducted among MRKH patients via the French national association network from March to August 2020. The questionnaire comprised twenty-eight questions about their desire for parenthood, their condition's characteristics and previous reconstructive procedures, opinions and knowledge about UTx.

RESULTS

Among the 148 participants, 88 % reported a desire for parenthood, and 61 % opted for UTx as their first choice to reach this aim. The possibility of bearing a child and having the same genetic heritage were the main motivations. Once informed about the usual course of an UTx protocol, only 13 % of the participants changed their mind and 3 out of 4 of them opted for UT.

CONCLUSION

Uterus transplantation seems to be the first option to reach motherhood in patients suffering from MRKH syndrome. The development of UTx programs could meet the demands of this already well-informed population.

Three-year follow-up results of two children born from a transplanted uterus

AIMS

To evaluate the 3-year follow-up results of two children delivered at our institution in 2019 from mothers with a transplanted uterus.

METHODS

Observational data on pregnancy outcomes, neonatal course, and growth trajectory in two children born to mothers after uterus transplantation, including 3-year follow-up and neurodevelopmental status assessed using the Bayley Scales of Infant and Toddler Development, third edition (Bayley-III).

RESULTS

Both children were born prematurely via uneventful caesarean sections, to mothers with Mayer-Rokitansky-Küster-Hauser syndrome and a transplanted uterus. An acute caesarean section was performed in one mother because of the onset of regular uterine contractions at 34 weeks and 6 days of pregnancy; in the other mother, an elective caesarean section was performed at 36 weeks and 2 days of gestation. The children were born healthy with no congenital malformations. They had an uneventful postnatal course and showed a normal growth trajectory during 3 years of follow-up. The Bayley-III neurodevelopmental scores of both children were within the normal ranges at ages 2 and 3 years.

CONCLUSION

Though pregnancy after uterus transplantation is associated with the risk of premature delivery, no abnormalities were observed in the neonatal course and 3-year follow-up results, including the neurodevelopmental status, of two children born prematurely to mothers with a transplanted uterus. This is the first report on neurodevelopmental outcomes in children born after uterus transplantation. More data on children born after this radical procedure of uterine factor infertility treatment are required to support our promising results.

Hypothermic machine perfusion for uterus transplantation

OBJECTIVE

To describe the feasibility of hypothermic machine perfusion (HMP) in uterus transplantation (UT) to potentially improve the preservation of the uterus and enhance graft preservation in the donation after brainstem death (DBD) context. Uterus transplantation is a new surgical approach to treating absolute uterine infertility; it can be performed after living donation or after DBD. In the DBD context, the uterus is typically the last organ removed after other vital organs, with the exception of the Baylor team, which removes the uterus first. This key aspect imposes an unavoidable mild temperature ischemia for >1 hour on the uterus during the removal of the vital abdominal and chest organs. In renal transplantation, the perfusion machine reduces the risk of delayed graft function; thus, we hypothesized that machine perfusion could result in a reduction of uterus graft dysfunction. The uterus graft dysfunction could be expressed by a low embryo implantation rate, pregnancy loss, or vascular pregnancy diseases such as preeclampsia or fetal growth restriction." To date, static cold storage of the uterus is the only standard method for preservation before transplantation. HMP is an emerging method that could potentially improve the preservation of the uterus to enhance graft preservation in the DBD context.

DESIGN

This video article shows all the technical details of using the HMP for uterine transplantation.

SETTING

University.

ANIMALS

Porcine model.

INTERVENTION

Porcine uterus was retrieved from a DBD domestic animal model and flushed with KPS MP (Bridge To Life Ltd in UK) at 4 °C. After vascular preparation on the back table, the uterus was perfused using KPS MP through a cannula in the aorta using the VitaSmart device (Bridge To Life Ltd in UK) for 18 hours. Then, the uterus was transplanted to the porcine recipient.

MAIN OUTCOME MEASURES

The macroscopic appearance of the uterus at the end of HMP and the assessment of the uterus vascularization after transplantation in the recipient compared with the native uterus.

RESULTS

This video shows the cannulation of the iliac vessels, cooling and removal of the uterus on a porcine model, uterus preservation using HMP during 18 hours, and then UT in a new recipient pig with the reperfusion of the transplanted uterus next to the native, intact uterus of the recipient. The macroscopic appearance of the uterus at the end of HMP appeared viable and was perfectly flushed. The assessment of the uterus vascularization after transplantation in the recipient was similar to that of the native uterus. To our knowledge, we describe here for the first time the UT procedure in DBD context on an animal model and the use of HMP for uterus preservation in UT programs; this could increase the number of uterine grafts available for a greater number of female recipients.

CONCLUSION

Hypothermic machine perfusion could allow the duration of cold ischemia to be prolonged without altering the uterine graft. Nevertheless, this assertion has to be validated in a human context.

[Uterine transplantation, ethical and social aspects]

Uterine transplantation is now a possible treatment for absolute uterine infertility. It is currently proposed to women with Mayer-Rokitansky-Küster-Hauser syndrome but indications will likely to expand in the upcoming years. Despite the progressive standardization of the surgical technique and the reduction in perioperative morbidity for both donors and recipients, the number of transplants performed worldwide remains very low compared to the number of women potentially in need. This is partly due to the singularity of uterine transplantation: the uterus is not a vital organ since one can live without a uterus. It is a temporary transplantation that is not performed to extend life but to improve its quality, responding above all to a desire to conceive and bear a child. Beyond the strictly technical aspect, these particularities raise many ethical questions, both on an individual and social level, which should make us question the real place uterine transplantation should take in our society. Answering these questions will allow us to provide better guidance for future eligible couples and to anticipate ethical problems on the long run.

Imaging of Uterine Transplantation

Uterus transplantation (UTx) is a novel procedure being studied as a treatment of absolute uterine factor infertility. Imaging plays an important role throughout the life cycle of a uterus transplant. In this review, we will first describe the surgical technique of UTx. The article will then focus on the importance of imaging in the evaluation of potential recipients and donors and during the immediate post-surgical time course as graft viability is established. Imaging as part of including in vitro fertilization, pregnancy, and complications will also be discussed.

Pregnancy management and outcome after uterus transplantation

Uterus transplantation is a novel approach in women whose uterus is absent or severely abnormal. However, it is still an experimental procedure that poses risks to both mother and baby. To date, 32 live births after uterus transplantation have been reported in peer-reviewed journals, with several maternal, fetal and neonatal complications. The most common complications were preterm delivery, hypertensive disorders and placenta previa. Four patients experienced episodes of transplant rejection during pregnancy. The appropriate management of complicated and non-complicated pregnancies following uterus transplantation is still unresolved. In this review, obstetric outcomes after uterus transplantation and optimal management during pregnancy are discussed in light of the available data. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Who should provide the uterus? The ethics of live donor recruitment for uterus transplantation

Uterus transplantation (UTx) is an experimental surgery likely to face the issue of organ shortage. In my article, I explore how this issue might be addressed by changing the prevailing practices around live uterus donor recruitment. Currently, women with children - often the mothers of recipients - tend to be overrepresented as donors. Yet, other potentially eligible groups who may have an interest in providing their uterus - such as transgender men, or cisgender women who do not wish to gestate or to have children - tend to be excluded as potential donors. Moving forward, I recommend that donor inclusion criteria for UTx be broadened to be more inclusive of these latter groups.

Attitudes, knowledge, and perceptions among women toward uterus transplantation and donation in the United Kingdom

Objective

To assess the motivations and perceptions of the general public in the United Kingdom toward donating their uterus for Uterus Transplantation after death (UTx).

Design

A cross sectional study.

Setting

A 32-item electronic questionnaire.

Population

One hundred fifty nine females over the age of 16 living in the United Kingdom, consented and took part in the study.

Main outcome measures

The motivations and perceptions toward UTx among the general public including the willingness to donate and barriers preventing donation.

Results

One hundred fifty nine women completed the questionnaire. The majority had never heard of UTx (n = 107, 71%) and most were not aware the uterus could be donated after death (n = 130, 92%). 43% of the cohort were willing to donate their uterus after death (n = 57). 8% stated they wished to donate their organs but not their uterus (n = 10). 30% of women (n = 42) believed the child born following UTx would have genetic links to the donor. Over half of the respondents (n = 65, 51%) strongly agreed or agreed they would feel joy in the knowledge that donation would lead to bringing a new life into the world. A quarter of respondents strongly agreed or agreed (n = 45, 25%) that the use of their uterus by another woman would feel like an extension of life.

Conclusion

The findings indicate a favorable opinion toward UTx and a positive attitude toward donation of the uterus after death among the general public in the United Kingdom. The findings also highlight the need for education around UTx now this therapeutic option is available.

Overview of pregnancy in solid-organ transplantation

PURPOSE OF REVIEW

Pregnancy in solid organ transplantation (SOT) is a very complex part of transplant medicine wherein there is scarce information available in the literature. Solid organ transplant recipients often have comorbidities, such as hypertension and diabetes, which add additional risk to a pregnancy.

RECENT FINDINGS

We present this review article on the various aspects of different types of immunosuppressant medications used in pregnancy with added inputs on contraception and fertility after transplant. We described the antepartum and postpartum considerations and discussed the adverse effects of the immunosuppressive medications. Maternal and fetal complications of each SOT have been also discussed in this article.

SUMMARY

This article will serve as the primary review articles for the use of immunosuppressive medications during pregnancy with consideration during pregnancy after SOT.

Fertility preservation and realignment in transgender women

Medical care for transgender people is multi-faceted and attention to individual reproductive aspirations and planning are an essential, yet often overlooked aspect of care. Given the impact of hormonal therapy and other gender affirmation procedures on reproductive function, extensive counselling and consideration of fertility preservation is recommended prior to their commencement. This review article explores the reproductive aspirations of transgender women and considers the current disparity between stated desires regarding utilisation of fertility preservation services. Current fertility preservation options and prospective treatments currently showing promise in the research arena are explored.

Immunosuppression in Uterus Transplantation: Experience From the Dallas Uterus Transplant Study

BACKGROUND

Uterus transplantation is a temporary transplant allowing women with absolute uterine factor infertility to experience pregnancy and childbirth. The degree of immunosuppression (IS) required to prevent rejection while minimizing toxicity to the recipient and fetus remains an area of investigation.

METHODS

In this article, we describe immunosuppressive therapy, rejection episodes, infections, and adverse events in 14 uterus transplant recipients. Induction consisted of antithymocyte globulin and methylprednisolone. Ten recipients (71%) received no steroids postoperatively, and 4 (29%) had steroids tapered off at 42 d. All received oral tacrolimus, either immediate release (n = 2, 14%) or extended release (n = 12, 86%). Mycophenolate was used in 4 cases (29%), de novo azathioprine in 9 (64%), and de novo everolimus in 1 (7%).

RESULTS

Sixteen clinically silent, treatment-responsive rejection episodes occurred in 10 recipients. Five recipients (36%) experienced acute kidney injury. In 3 recipients, IS was discontinued due to renal dysfunction. Eleven infection episodes were noted in 7 recipients. No babies had congenital abnormalities.

CONCLUSIONS

Our experience demonstrates that safe IS regimens can be used for uterus transplant recipients before and during pregnancy.

The impact of COVID-19 on the motivations of women seeking a uterus transplant

Aim: The aim of this study was to investigate the change if any, in the motivations of women seeking a UTx and determine the impact of the COVID-19 pandemic. Methods: A cross-sectional survey. Results: 59% of women answered they were more motivated in achieving a pregnancy following the COVID-19 pandemic. 80% strongly agreed or agreed the pandemic had no impact on their motivation for a UTx, and 75% strongly agreed or agreed their desire for a baby strongly outweighs the risks of undergoing a UTx during a pandemic. Conclusion: Women continue to express a high level of motivation and desire for a UTx despite the risks imposed by the COVID-19 pandemic.

Living uterus donors' perceptions of decision-making and informed consent: a qualitative study of the Dallas Uterus Transplant Study participants

Uterus transplantation is a growing field, but little is known about living uterus donors' perceptions of informed consent or their decision-making processes. This study used semistructured interviews to collect information regarding uterus donors' experiences with uterus donation, perceptions of the informed consent process, and information on how they decided to pursue uterus donation. Interviews were coded for thematic analysis. Three major themes emerged in this study. First, the decision-making process was based on individuals' motivations, rationale, and considerations of alternative contributions to help other women with infertility. Second, participants described how they felt about the process of informed consent, their decision-making processes, and how their experiences compared with their expectations. Third, participants discussed how uterus donation was a valuable experience. This study found that living uterus donors are motivated to give another woman the opportunity to experience pregnancy and childbirth. They were satisfied with the informed consent process, their experiences were in line with their expectations, and the value of uterus donation was associated with the act of donation itself. Our findings suggest that living donor uterus programs should develop robust informed consent processes that provide detailed information about uterus donation and encourage shared decision-making with potential uterus donors.

Neonatal Outcomes after Uterus Transplantation: Dallas Uterus Transplant Study

OBJECTIVE

Limited data are available on the outcome of infants born after uterus transplantation. Our aim was to describe the hospital course and laboratory findings in the first 2 months of life of the 12 infants born in the Dallas UtErus Transplant Study (DUETS).

STUDY DESIGN

Based on the trial protocol, information about infants was collected in a prospective fashion, including infant demographics, hospital course, and laboratory values.

RESULTS

Twelve infants were delivered, all by cesarean section, from 11 mothers who had undergone uterus transplantation (one mother had two pregnancies and delivered two babies). All pregnancies were singleton. The mothers received immunosuppressive therapy, and one had a rejection episode that was detected during pregnancy. The rejection episode resolved after steroid treatment. The infants had a median gestational age of 36^6/7 weeks (range: 30^6/7-38^0/7 weeks) and median birth weight of 2,920 g (range: 1,770-3,470 g). The lowest Apgar's score at 5 minutes was 8. All infants were appropriate size for gestational age. Two infants presented with bandemia but negative blood cultures. At 2 months of age, all infants achieved the developmental and behavioral milestones outlined by the American Academy of Pediatrics.

CONCLUSION

The 12 infants born from mothers with uterus transplants had a neonatal course that reflected the gestational age at delivery. No baby was born with an identified malformation or organ dysfunction. Longer follow-up and a larger number of infants are needed to confirm these observations.

KEY POINTS

· Normal fetal development after uterus transplantation.. · No baby was born with malformations or showed any organ dysfunction.. · At 2 months, all infants achieved appropriate developmental and behavioral milestones..

Early Uterine Transplant Graft Loss Due to Thrombosis: Single-Center Experience With Causes, Prevention, Diagnosis, and Treatment

Uterus transplantation (UTx) is a promising treatment option for women who wish to give birth but suffer from absolute uterine factor infertility. This paper presents an interim analysis of a trial focusing on the causes, prevention, diagnosis, and management of graft thrombosis. Our team analyzed 10 cases of UTx (recipients numbered 1 to 10). Early thrombosis developed in 2 of 10 (20 %) recipients, and thrombectomy and temporary viability preservation were achieved in both cases. However, re-thrombosis developed in both cases, and a graft hysterectomy was carried out. In recipient number 2, vascular changes might have contributed to graft thrombosis. The histopathological finding of the explant revealed subintimal excentric fibrosis with focal sclerotic changes. In recipient number 8, thrombosis was facilitated by external compression of the vascular pedicles by the hematoma as well as production of de novo donor-specific antibodies. Thrombosis led to graft loss in both cases despite an attempt at a thrombectomy. Therefore, the focus must be on the prevention including a thorough evaluation of the donor candidate. In the postoperative course, perfusion is closely followed-up with an ultrasound, Doppler flow monitoring, and macroscopic evaluation of the cervix. In the case that findings are unclear, a relaparotomy should be promptly indicated. If thrombosis is revealed, a thrombectomy and an attempt to salvage of the graft are indicated; however, the role of this strategy is questionable due to the low chance of long-term success. The indication of upfront graft removal and early re-transplantation in the treatment of uterine graft remains debatable.

Tissue Engineering in Gynecology

Female gynecological organ dysfunction can cause infertility and psychological distress, decreasing the quality of life of affected women. Incidence is constantly increasing due to growing rates of cancer and increase of childbearing age in the developed world. Current treatments are often unable to restore organ function, and occasionally are the cause of female infertility. Alternative treatment options are currently being developed in order to face the inadequacy of current practices. In this review, pathologies and current treatments of gynecological organs (ovaries, uterus, and vagina) are described. State-of-the-art of tissue engineering alternatives to common practices are evaluated with a focus on in vivo models. Tissue engineering is an ever-expanding field, integrating various domains of modern science to create sophisticated tissue substitutes in the hope of repairing or replacing dysfunctional organs using autologous cells. Its application to gynecology has the potential of restoring female fertility and sexual wellbeing.

Uterus Transplantation: Revisiting the Question of Deceased Donors versus Living Donors for Organ Procurement

Uterus transplantation is a surgical treatment for women with congenital or acquired uterine factor infertility. While uterus transplantation is a life-enhancing transplant that is commonly categorized as a vascular composite allograft (e.g., face or hand), it is similar to many solid organ transplants (e.g., kidney) in that both living donors (LDs) and deceased donors (DDs) can be utilized for organ procurement. While many endpoints appear to be similar for LD and DD transplants (including graft survival, time to menses, livebirth rates), there are key medical, technical, ethical, and logistical differences between these modalities. Primary considerations in favor of a LD model include thorough screening of donors, enhanced logistics, and greater donor availability. The primary consideration in favor of a DD model is the lack of physical or psychological harm to a living donor. Other important factors, that may not clearly favor one approach over the other, are important to include in discussions of LD vs. DD models. We favor a stepwise approach to uterus transplantation, one in which programs first begin with DD procurement before attempting LD procurement to maximize successful organ recovery and to minimize potential harms to a living donor.

Perinatal considerations for care of transgender and nonbinary people: a narrative review

PURPOSE OF REVIEW

The visibility of the lesbian, gay, bisexual, transgender, and queer (LGBTQ+) communities, specifically the transgender and nonbinary (TGNB) communities, continues to grow. However, there is little description, much less guidance toward optimizing, the pregnancy-related care of TGNB people. The overarching goal of this paper is to provide guidance that aids in reimagining obstetrics to include people of all genders.

RECENT FINDINGS

This article will review current literature and provide recommendations specific to the hospital birthing environment to help address the lack of knowledge regarding pregnancy-related care of TGNB individuals. This care is further divided into three main times: (1) preconception, antepartum care, and triage, (2) intrapartum, and (3) postpartum. We also discuss considerations for the general medical care of TGNB individuals.

SUMMARY

Understanding facilitators and barriers to gender affirming pregnancy-related care of TGNB individuals are first steps toward providing a respectful, affirming, and evidence-based environment for all patients, especially TGNB individuals. Here we provide context, discussion, and resources for providers and TGNB patients navigating pregnancy-related care. Lastly, this review challenges researchers and clinicians with future directions for the care of TGNB individuals in this continually expanding field.

Uterine transplantation: A maternal-fetal medicine perspective

Uterine transplantation is a novel approach to solving a clinical problem faced by women with uterine factor infertility whose desire to parent includes a desire to give birth. The ethical precepts used for other solid organ transplants are helpful in developing normative frameworks for understanding this experimental therapy. Nevertheless, both fetal and neonatal risks complicate this calculus and therefore it is useful to incorporate analyses used in other realms of maternal-fetal medicine to understand and justify this research. Preliminary data on maternal and neonatal outcomes from the many centers exploring this technique are encouraging, but as these techniques move into mainstream care, ongoing vigilance will be necessary to ensure that women and their families are afforded similar protections required of research protocols. Uterine transplantation is a captivating topic for the myriad ethical issues it raises. Many of these issues have been analyzed extensively in the literature since the marvel of solid organ transplantation was first realized in the 1950s. But we have now been collecting data on uterine transplantation since the first successful birth in 2015¹ and the questions raised have morphed very quickly from "Can we do this?" to "Should we do this?" and "How should we do this?" The good news for patients and the public is that bioethicists have been front and center in participating in and helping to inform the rolling out of this innovative treatment for rare forms of infertility. The model for such an integrative role of ethics in uterine transplantation programs grew out of similar programs in high risk obstetrical procedures such as the repair of fetal meningomyelocele trials.² The goal of this review is to outline some of the key issues these transplantations raise from the perspective of maternal-fetal medicine, a field well acquainted with the dilemmas that may arise in maximizing outcomes for both pregnant women and their fetuses.

Relationship between uterine veins, ureter and hypogastric nerves for uterine transplantation: an anatomic study

BACKGROUND

Uterine transplantation is on the rise worldwide. In contrast to its arterial anatomy, venous drainage of the uterus is poorly defined in the literature. Our aim was to provide a standardized description of uterine veins through a multimodal approach to establish anatomical landmarks for the uterine transplantation surgeon.

METHODS

Data were obtained from: (1) an anatomical study of eight fresh female cadavers (16 hemipelves) studied separately by an extrafascial dissection from the iliac bifurcation to the uterine pedicle, with analysis of the urinary tract and nerve structures; and (2) a virtual anatomical study from the Anatomage® Table comprising a high-fidelity virtual reconstruction of two deceased female subjects by imaging and anatomical methods.

RESULTS

An inconstant duality of uterine veins was identified: a deep uterine vein of larger caliber, and a superficial uterine vein observed in 25% of cases. A close relationship of the ureter passing posterior to the superficial uterine vein and anterior to the deep uterine vein was evident in the parametrium. The inferior hypogastric plexus was identified in all cases immediately behind the deep uterine vein. The data obtained from the fresh female cadavers were validated by the Anatomage® Table.

CONCLUSIONS

We describe the close relationship of the uterine veins with the ureter and the inferior hypogastric plexus. This knowledge represents a surgical landmark to support the success of uterine transplantation by respecting both the graft and the safety of the living donor by limiting the risk of injuries during uterus procurement. This article is protected by copyright. All rights reserved.

Uterine Transplantation: Recipient Patient Populations

Uterine transplantation is an emerging treatment for patients with uterine factor infertility (UFI). In order to determine patient candidacy for transplant, it is imperative to understand how to identify, counsel and treat uterine transplant recipients. In this article, we focus on patient populations with UFI, whether congenital or acquired, including Mayer-Rokitansky-Kuster-Hauser, complete androgen insensitivity syndrome, hysterectomy, and other causes of nonabsolute UFI. Complete preoperative screening of recipients should be required to assess the candidacy of each individual prior to undergoing this extensive treatment option.

Immunologic and Infectious Concerns in Uterus Transplantation

Pharmacologic immunosuppression is required for the success of uterus transplantation but can provoke several complications for the transplant recipient. In this review, we discuss the immunologic complications that can occur in the uterus transplant recipient. First, we provide the latest update on immunosuppression regimens used by programs throughout the world. Next, we discuss the prevalence, mechanisms, treatment, and outcome of rejection in uterus transplant recipients. Finally, we discuss infectious complications of varying severity alongside their treatment and impact.

Genetic Screening and Teratogenic Exposures: Considerations in Caring for the Uterus Transplant Patient

Counseling the uterus transplant patient requires an enhanced knowledge of unique genetic challenges that include an understanding of the spectrum of Mayer-Rokitansky-Küster-Hauser syndrome. Patients should understand their options for genetic screening and testing including preimplantation genetic testing for aneuploidy, genetic screening, and diagnostic testing. This patient population is potentially at risk for fetal anomalies due to the increased susceptibility to infections, such as cytomegalovirus. There are management strategies to minimize this risk. The risk of teratogenicity from mycophenolate is eliminated by a washout period before embryo transfer.

Reproductive Technology Considerations in Uterus Transplant

Uterus transplantation (UTx) provides a new pathway to parenthood for patients with absolute uterine factor infertility. The application of reproductive technologies, such as in vitro fertilization, embryo cryopreservation, and frozen embryo transfers, for this unique population, is particularly nuanced and continually evolving. There are important pretransplant and posttransplant reproductive considerations for physicians and patients anticipating UTx. As with any rapidly evolving medical innovation, efforts to consolidate experiences and knowledge by centers offering UTx is paramount.

Procurement of Uterus in a Deceased Donor Multi-Organ Donation National Program in France: A Scarce Resource for Uterus Transplantation?

Uterus transplantation is a new possibility for women suffering from absolute uterine infertility to become pregnant and have children. In the case of a deceased donor, a list of exclusion criteria is defined to ensure the high quality of the uterus graft. This study evaluates the number of potentially available uterus grafts based on the pre-defined exclusion criteria in a national deceased donor multi-organ donation program in France. We analyzed the data reported in the CRISTAL database regarding all women aged 18 to 60 on whom organ procurement was performed between 2014 and 2019. Potential deceased women donors were classified into three categories: very ideal donor, ideal donor, and expanded criteria donor. Between 2014 and 2019, 4544 women underwent organ procurement. Using the very ideal donor, ideal donor, and expanded criteria donor classification, we found that, respectively, only 124, 264, and 936 donors were potentially eligible for UTx. This represents 2.8 per million people (PMP) very ideal donors, 3.8 PMP ideal donors, 8.6 PMP expanded criteria donors (ECDs). The restricted number of grafts requires a complementary strategy of living and deceased donors to meet the demand of all women with AUI.

Collagen-based materials in reproductive medicine and engineered reproductive tissues

Collagen, the main component of mammal skin, has been traditionally used in leather manufacturing for thousands of years due to its diverse physicochemical properties. Collagen is the most abundant protein in mammals and the main component of the extracellular matrix (ECM). The properties of collagen also make it an ideal building block for the engineering of materials for a range of biomedical applications. Reproductive medicine, especially human fertility preservation strategies and reproductive organ regeneration, has attracted significant attention in recent years as it is key in resolving the growing social concern over aging populations worldwide. Collagen-based biomaterials such as collagen hydrogels, decellularized ECM (dECM), and bioengineering techniques including collagen-based 3D bioprinting have facilitated the engineering of reproductive tissues. This review summarizes the recent progress in applying collagen-based biomaterials in reproductive. Furthermore, we discuss the prospects of collagen-based materials for engineering artificial reproductive tissues, hormone replacement therapy, and reproductive organ reconstruction, aiming to inspire new thoughts and advancements in engineered reproductive tissues research.

Graphical abstract

The journey from infertility to uterus transplantation: A qualitative study of the perspectives of participants in the Dallas Uterus Transplant Study

OBJECTIVE

To assess how absolute uterine factor infertility affects women who undergo uterus transplantation, how uterus transplantation impacts women with absolute uterine factor infertility and how uterus transplant recipients view uterus transplantation in terms of their reproductive autonomy.

DESIGN

Qualitative semi-structured interview study.

SETTING

Uterus transplant programme in a large academic medical centre in the USA.

POPULATION/SAMPLE

Twenty one uterus transplant recipients.

METHODS

A medical chart review was conducted to collect patient demographic information and clinical outcomes. Semi-structured interviews collected information regarding participants' experience.

MAIN OUTCOME MEASURE(S)

The outcomes of interest were participants' experience of infertility, experience with uterus transplantation and general perceptions of uterus transplantation.

RESULTS

Six participants were pregnant (one with a second child), six had experienced early graft failure and removal, five had delivered a healthy baby, and four had a viable graft and were awaiting embryo transfer. The primary themes identified were: the negative impact of absolute uterine factor infertility diagnosis on psychological wellbeing, relationships and female identity; the positive impact of uterus transplantation on healing the emotional scars of absolute uterine factor infertility, female identity and value of research trial participation and the perception of uterus transplantation as an expansion of reproductive autonomy. All participants reported that uterus transplantation was worthwhile, regardless of individual outcome.

CONCLUSION

Absolute uterine factor infertility has a negative impact on women from a young age, affects multiple relationships and challenges female identity. Uterus transplantation helps to reverse this impact, transforming women's life narrative of infertility and enhancing female identity.

TWEETABLE ABSTRACT

Absolute uterine factor infertility (AUFI) adversely affects women. Uterus transplantation helps mitigate the negative impact of AUFI, by transforming women's life narratives of infertility and enhancing female identity.

Uterus transplantation - donor and recipient work-up

PURPOSE OF REVIEW

Uterus transplantation (UTx) is transitioning from an experimental procedure to a clinical treatment for absolute uterine factor infertility (AUFI). Standardized protocols for the evaluation and selection of donors and recipients that maximize chances of success - a healthy live birth - are needed.

RECENT FINDINGS

To date, recipient eligibility has been limited to otherwise healthy women with AUFI who are of childbearing age and are good candidates for in-vitro fertilization (IVF). For donors (living or deceased), selection criteria vary, apart from basic requirements of blood-type compatibility and freedom from critical infectious diseases, but generally require a term birth and a uterus free from uterine pathologies. The stepwise evaluation process for candidate recipients and living donors moves through health screening (medical and psychosocial); initial selection committee review; IVF (recipients only); and final selection committee review. This eliminates candidates with poor chances of success before exposure to unnecessary risks.

SUMMARY

The currently stringent selection criteria for prospective recipients and donors will likely broaden, as UTx becomes more widely available. Continued research is needed to define the donor, recipient and uterine graft factors associated with successful outcomes, and to support the development of standardized selection criteria.

Uterus transplantation: ethical considerations

PURPOSE OF REVIEW

Uterus transplantation (Utx) offers women with absolute uterine factor infertility the opportunity to carry their own pregnancies. As Utx transitions from an experimental to standard clinical procedure, we review the status of the ethical issues applicable to the stakeholders involved.

RECENT FINDINGS

With more than 65 Utx procedures reported to date, evidence is accruing that enables the chance of success - a live birth - for the recipient to be weighed against the risks the recipient incurs through the Utx process, as well as risks to living donors undergoing surgery, to children exposed in utero to immunosuppressants and the uterine graft environment, and to third parties related to uterus procurement from multiorgan deceased donors. Experience has also informed aspects of recipient and donor autonomy that must be safeguarded.

SUMMARY

Clinical trial results provides a basis for weighing the interests of the stakeholders implicated in Utx, and so can inform transplant centers' and regulatory bodies' development of policies and protocols that will determine access to Utx and allocation of organs, together with other considerations of justice. Additional evidence, particularly on long-term outcomes, is needed, and new questions can be expected to arise as access to and indications for Utx broaden.

Uterus transplantation: the importance of uterine natural killer cells

PURPOSE OF REVIEW

Murine studies have established that uterine natural killer (uNK) cells are critical regulators of normal placentation and fetal development in mammals. However, the biology of uNK cells in humans remains poorly understood. This ignorance represents a costly knowledge gap, as disordered placentation is thought to underpin a variety of pregnancy complications that impact maternal and neonatal health. In the context of uterus transplantation (UTx), uNK cells are anticipated to play a critical role within the allograft. Here, we review the current understanding of uNK cells in pregnancy biology and explore how this critically important cell population may contribute to pregnancy and graft outcomes in uterus transplant recipients.

RECENT FINDINGS

Recent studies have characterized differences in NK cell populations between anatomic compartments in humans. In the endometrium, at least five phenotypically and functionally distinct subpopulations of uNK cells have been identified, with research into mechanisms regulating their differentiation and function currently underway.

SUMMARY

Further elucidating uNK cell biology has the potential to influence the outcomes of pregnancy and UTx and benefit human health. UTx is a unique opportunity to study uNK cell biology and may shed light on mechanisms by which immunological tolerance is established at the maternal-fetal interface.

Immunosuppression after uterus transplantation

PURPOSE OF REVIEW

Clinical uterus transplantation (UTx) is growing rapidly. The procedure represents the only therapy for women with absolute uterine factor infertility to give birth to a biological baby. Immunosuppression after UTx needs to carefully balance effects with the healthy mother and baby. Unique for UTx is the 'temporary' character of the procedure with a transplant hysterectomy being performed after delivery. Most of the practice on immunosuppression in UTx is currently based on the experience in solid organ transplantation (SOT).

RECENT FINDINGS

Clinical UTx-trials have been performed in centers worldwide during the recent years and experience on immunosuppression has accumulated.

SUMMARY

Immunosuppression in UTx has been successfully applied as maintenance treatment in addition to effectively treating acute T- and B-cell mediated rejections. Understanding the biology of UTx in more detail is expected to refine future approaches.