-
Development (Cambridge, England) May 2023Embryo implantation in humans is interstitial, meaning the entire conceptus embeds in the endometrium before the placental trophoblast invades beyond the uterine mucosa... (Review)
Review
Embryo implantation in humans is interstitial, meaning the entire conceptus embeds in the endometrium before the placental trophoblast invades beyond the uterine mucosa into the underlying inner myometrium. Once implanted, embryo survival pivots on the transformation of the endometrium into an anti-inflammatory placental bed, termed decidua, under homeostatic control of uterine natural killer cells. Here, we examine the evolutionary context of embryo implantation and elaborate on uterine remodelling before and after conception in humans. We also discuss the interactions between the embryo and the decidualising endometrium that regulate interstitial implantation and determine embryo fitness. Together, this Review highlights the precarious but adaptable nature of the implantation process.
Topics: Pregnancy; Humans; Female; Placenta; Embryo Implantation; Endometrium; Uterus; Embryo, Mammalian
PubMed: 37254877
DOI: 10.1242/dev.201507 -
Fertility and Sterility Jun 2022Immune cells are essential for endometrial receptivity to embryo implantation and early placental development. They exert tissue-remodeling and immune regulatory... (Review)
Review
Immune cells are essential for endometrial receptivity to embryo implantation and early placental development. They exert tissue-remodeling and immune regulatory roles-acting to promote epithelial attachment competence, regulate the differentiation of decidual cells, remodel the uterine vasculature, control and resolve inflammatory activation, and suppress destructive immunity to paternally inherited alloantigens. From a biological perspective, the endometrial immune response exerts a form of "quality control"-it promotes implantation success when conditions are favorable but constrains receptivity when physiological circumstances are not ideal. Women with recurrent implantation failure and recurrent miscarriage may exhibit altered numbers or disturbed function of certain uterine immune cell populations-most notably uterine natural killer cells and regulatory T cells. Preclinical and animal studies indicate that deficiencies or aberrant activation states in these cells can be causal in the pathophysiological mechanisms of infertility. Immune cells are, therefore, targets for diagnostic evaluation and therapeutic intervention. However, current diagnostic tests are overly simplistic and have limited clinical utility. To be more informative, they need to account for the full complexity and reflect the range of perturbations that can occur in uterine immune cell phenotypes and networks. Moreover, safe and effective interventions to modulate these cells are in their infancy, and personalized approaches matched to specific diagnostic criteria will be needed. Here we summarize current biological understanding and identify knowledge gaps to be resolved before the promise of therapies to target the uterine immune response can be fully realized.
Topics: Abortion, Habitual; Animals; Embryo Implantation; Endometrium; Female; Humans; Placenta; Pregnancy; Uterus
PubMed: 35618356
DOI: 10.1016/j.fertnstert.2022.04.023 -
Reproductive Biology and Endocrinology... Aug 2022During implantation, a symphony of interaction between the trophoblast originated from the trophectoderm of the implanting blastocyst and the endometrium leads to a... (Review)
Review
During implantation, a symphony of interaction between the trophoblast originated from the trophectoderm of the implanting blastocyst and the endometrium leads to a successful pregnancy. Defective interaction between the trophoblast and endometrium often results in implantation failure, pregnancy loss, and a number of pregnancy complications. Owing to ethical concerns of using in vivo approaches to study human embryo implantation, various in vitro culture models of endometrium were established in the past decade ranging from two-dimensional cell-based to three-dimensional extracellular matrix (ECM)/tissue-based culture systems. Advanced organoid systems have also been established for recapitulation of different cellular components of the maternal-fetal interface, including the endometrial glandular organoids, trophoblast organoids and blastoids. However, there is no single ideal model to study the whole implantation process leaving more research to be done pursuing the establishment of a comprehensive in vitro model that can recapitulate the biology of trophoblast-endometrium interaction during early pregnancy. This would allow us to have better understanding of the physiological and pathological process of trophoblast-endometrium interaction during implantation.
Topics: Blastocyst; Embryo Implantation; Embryo, Mammalian; Endometrium; Female; Humans; Pregnancy; Trophoblasts
PubMed: 35964080
DOI: 10.1186/s12958-022-00973-8 -
Reproductive Biomedicine Online Nov 2020Recurrent implantation failure (RIF) after IVF is a challenging topic for clinicians and can be a devastating reality for some patients with infertility. The purpose of... (Review)
Review
Recurrent implantation failure (RIF) after IVF is a challenging topic for clinicians and can be a devastating reality for some patients with infertility. The purpose of this guideline from the Canadian Fertility and Andrology Society (CFAS) is to provide the most relevant evidence to date for the assessment and management of RIF. This guideline was developed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach. This guideline recognizes the presence of heterogeneity in the definition of RIF. Recommendations are offered here on the investigation of RIF and management options that may increase the chance of a live birth.
Topics: Embryo Implantation; Female; Fertilization in Vitro; Humans; Infertility; Pregnancy; Recurrence
PubMed: 32962928
DOI: 10.1016/j.rbmo.2020.08.007 -
The EMBO Journal Sep 2023Embryo implantation into the uterus marks a key transition in mammalian development. In mice, implantation is mediated by the trophoblast and is accompanied by a...
Embryo implantation into the uterus marks a key transition in mammalian development. In mice, implantation is mediated by the trophoblast and is accompanied by a morphological transition from the blastocyst to the egg cylinder. However, the roles of trophoblast-uterine interactions in embryo morphogenesis during implantation are poorly understood due to inaccessibility in utero and the remaining challenges to recapitulate it ex vivo from the blastocyst. Here, we engineer a uterus-like microenvironment to recapitulate peri-implantation development of the whole mouse embryo ex vivo and reveal essential roles of the physical embryo-uterine interaction. We demonstrate that adhesion between the trophoblast and the uterine matrix is required for in utero-like transition of the blastocyst to the egg cylinder. Modeling the implanting embryo as a wetting droplet links embryo shape dynamics to the underlying changes in trophoblast adhesion and suggests that the adhesion-mediated tension release facilitates egg cylinder formation. Light-sheet live imaging and the experimental control of the engineered uterine geometry and trophoblast velocity uncovers the coordination between trophoblast motility and embryo growth, where the trophoblast delineates space for embryo morphogenesis.
Topics: Female; Mice; Animals; Embryo Implantation; Blastocyst; Trophoblasts; Uterus; Embryonic Development; Mammals
PubMed: 37522872
DOI: 10.15252/embj.2022113280 -
Modelling the impact of decidual senescence on embryo implantation in human endometrial assembloids.ELife Sep 2021Decidual remodelling of midluteal endometrium leads to a short implantation window after which the uterine mucosa either breaks down or is transformed into a robust...
Decidual remodelling of midluteal endometrium leads to a short implantation window after which the uterine mucosa either breaks down or is transformed into a robust matrix that accommodates the placenta throughout pregnancy. To gain insights into the underlying mechanisms, we established and characterized endometrial assembloids, consisting of gland-like organoids and primary stromal cells. Single-cell transcriptomics revealed that decidualized assembloids closely resemble midluteal endometrium, harbouring differentiated and senescent subpopulations in both glands and stroma. We show that acute senescence in glandular epithelium drives secretion of multiple canonical implantation factors, whereas in the stroma it calibrates the emergence of anti-inflammatory decidual cells and pro-inflammatory senescent decidual cells. Pharmacological inhibition of stress responses in pre-decidual cells accelerated decidualization by eliminating the emergence of senescent decidual cells. In co-culture experiments, accelerated decidualization resulted in entrapment of collapsed human blastocysts in a robust, static decidual matrix. By contrast, the presence of senescent decidual cells created a dynamic implantation environment, enabling embryo expansion and attachment, although their persistence led to gradual disintegration of assembloids. Our findings suggest that decidual senescence controls endometrial fate decisions at implantation and highlight how endometrial assembloids may accelerate the discovery of new treatments to prevent reproductive failure.
Topics: Cellular Senescence; Coculture Techniques; Decidua; Embryo Implantation; Endometrium; Female; Humans; Organoids; Pregnancy; Stromal Cells
PubMed: 34487490
DOI: 10.7554/eLife.69603 -
Fertility and Sterility Nov 2018To assess the efficacy of an etonogestrel (ENG)-releasing contraceptive implant or the 52-mg levonorgestrel-releasing intrauterine system (LNG-IUS) in the control of... (Randomized Controlled Trial)
Randomized Controlled Trial
Control of endometriosis-associated pain with etonogestrel-releasing contraceptive implant and 52-mg levonorgestrel-releasing intrauterine system: randomized clinical trial.
OBJECTIVE
To assess the efficacy of an etonogestrel (ENG)-releasing contraceptive implant or the 52-mg levonorgestrel-releasing intrauterine system (LNG-IUS) in the control of endometriosis-associated pelvic pain.
DESIGN
Noninferiority randomized clinical trial in which women with endometriosis were assigned to use an ENG implant (experimental treatment) or an LNG-IUS (active comparator). Monthly follow-up visits were conducted up to 6 months.
SETTING
University teaching hospital.
PATIENT(S)
One hundred three women, with endometriosis-associated chronic pelvic pain, dysmenorrhea, or both for more than 6 months. In cases of deep endometriosis, vaginal ultrasonography and magnetic resonance imaging were used as additional diagnostic tools.
INTERVENTION(S)
The ENG implant or the LNG-IUS were inserted within the first 5 days of the menstrual cycle.
MAIN OUTCOME MEASURE(S)
Daily scores of noncyclic pelvic pain and dysmenorrhea were evaluated using a daily visual analogue scale. Health-related quality of life was evaluated using the Endometriosis Health Profile-30 questionnaire at baseline and up to 6 months. Bleeding patterns were assessed daily from a menstrual calendar.
RESULT(S)
Both contraceptives improved significantly the mean visual analogue scale endometriosis-associated pelvic pain and dysmenorrhea, without significant differences between treatment group profiles. Health-related quality of life improved significantly in all domains of the core and modular segments of the Endometriosis Health Profile-30 questionnaire, with no difference between both treatment groups. The most common bleeding patterns at 180 days of follow-up were amenorrhea and infrequent bleeding and infrequent bleeding and spotting among ENG implant and LNG-IUS users, respectively.
CONCLUSION(S)
In this noninferiority study both contraceptives improved significantly pelvic pain, dysmenorrhea, and health-related quality of life in endometriosis.
CLINICAL TRIAL REGISTRATION NUMBER
Clinicaltrials.gov under number NCT02480647.
Topics: Adult; Contraceptive Agents, Female; Desogestrel; Drug Implants; Drug Liberation; Endometriosis; Female; Follow-Up Studies; Humans; Intrauterine Devices, Medicated; Levonorgestrel; Pain Management; Pelvic Pain
PubMed: 30396557
DOI: 10.1016/j.fertnstert.2018.07.003 -
Journal de Gynecologie, Obstetrique Et... Dec 2016To establish guidelines of the French National College of Gynecologists and Obstetricians about post-abortion contraception. (Review)
Review
OBJECTIVE
To establish guidelines of the French National College of Gynecologists and Obstetricians about post-abortion contraception.
MATERIALS AND METHODS
A systematic review of the literature about post-abortion contraception was performed on Medline and Cochrane Database between 1978 and March 2016. The guidelines of the French and foreign scientific societies were also consulted.
RESULTS AND DISCUSSION
After an abortion, if the woman wishes to use a contraception, it should be started as soon as possible because of the very early ovulation resumption. The contraception choice must be done in accordance with the woman's expectations and lifestyle. The contraindications of each contraception must be respected. The long-acting reversible contraception, intra-uterine device (IUD) and implant, could be preferred (grade C) as the efficacy is not dependent on compliance. Thus, they could better prevent repeat abortion (LE3). In case of surgical abortion, IUD should be proposed and inserted immediately after the procedure (grade A), as well as the implant (grade B). In case of medical abortion, the implant can be inserted from the day of mifépristone, the IUD after an ultrasound examination confirming the success of the abortion (no continuing pregnancy or retained sac) (grade C).
Topics: Abortion, Induced; Contraceptive Agents, Female; Drug Implants; Female; Humans; Intrauterine Devices; Pregnancy
PubMed: 27773547
DOI: 10.1016/j.jgyn.2016.09.017 -
Frontiers in Endocrinology 2023The human endometrium is only receptive to an implanting blastocyst in the mid-secretory phase of each menstrual cycle. Such time-dependent alterations in function... (Review)
Review
The human endometrium is only receptive to an implanting blastocyst in the mid-secretory phase of each menstrual cycle. Such time-dependent alterations in function require intricate interplay of various factors, largely coordinated by estrogen and progesterone. Abnormal endometrial receptivity is thought to contribute to two-thirds of the implantation failure in humans and therefore significantly hindering IVF success. Despite the incontrovertible importance of endometrial receptivity in implantation, the precise mechanisms involved in the regulation of endometrial receptivity remain poorly defined. This is mainly due to a lack of proper models that recapitulate the environment of the receptive human endometrium. Organoids were recently established from human endometrium with promising features to better mimic the receptive phase. Endometrial organoids show long-term expandability and the capability to preserve the structural and functional characteristics of the endometrial tissue of origin. This three-dimensional model maintains a good responsiveness to steroid hormones and replicates key morphological features of the receptive endometrium , including pinopodes and pseudostratified epithelium. Here, we review the current findings of endometrial organoid studies that have been focused on investigating endometrial receptivity and place an emphasis on methods to further refine and improve this model.
Topics: Female; Humans; Endometrium; Menstrual Cycle; Blastocyst; Embryo Implantation; Organoids
PubMed: 37693361
DOI: 10.3389/fendo.2023.1158515 -
The New England Journal of Medicine Jun 1999Implantation of the conceptus is a key step in pregnancy, but little is known about the time of implantation or the relation between the time of implantation and the...
BACKGROUND
Implantation of the conceptus is a key step in pregnancy, but little is known about the time of implantation or the relation between the time of implantation and the outcome of pregnancy.
METHODS
We collected daily urine samples for up to six months from 221 women attempting to conceive after ceasing to use contraception. Ovulation was identified on the basis of the ratio of urinary estrogen metabolites to progesterone metabolites, which changes rapidly with luteinization of the ovarian follicle. The time of implantation was defined by the appearance of chorionic gonadotropin in maternal urine.
RESULTS
There were 199 conceptions, for 95 percent of which (189) we had sufficient data for analysis. Of these 189 pregnancies, 141 (75 percent) lasted at least six weeks past the last menstrual period, and the remaining 48 pregnancies (25 percent) ended in early loss. Among the pregnancies that lasted six weeks or more, the first appearance of chorionic gonadotropin occurred 6 to 12 days after ovulation; 118 women (84 percent) had implantation on day 8, 9, or 10. The risk of early pregnancy loss increased with later implantation (P<0.001). Among the 102 conceptuses that implanted by the ninth day, 13 percent ended in early loss. This proportion rose to 26 percent with implantation on day 10, to 52 percent on day 11, and to 82 percent after day 11.
CONCLUSIONS
In most successful human pregnancies, the conceptus implants 8 to 10 days after ovulation. The risk of early pregnancy loss increases with later implantation.
Topics: Abortion, Spontaneous; Embryo Implantation; Female; Humans; Pregnancy; Risk Factors; Time Factors
PubMed: 10362823
DOI: 10.1056/NEJM199906103402304