Endometrial Basis for Infertility in Women With Recurrent Implantation Failure and Pregnancy Loss

  • End date
    Sep 30, 2024
  • participants needed
  • sponsor
    Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Updated on 24 September 2021



Pregnancy loss is the most common complication of pregnancy. It occurs in roughly one-half

of natural conceptions. It most frequently occurs in the first 2 to 3 weeks of pregnancy. Researchers want to look at the lining of the uterus, called the endometrium, to see what role it plays in implantation and miscarriage.


To gain a better understanding of how normal and abnormal endometrium works.


Healthy, fertile women ages 18-42 who have had one prior child.


Participants will have 3 study visits.

At visit 1, participants will have a medical history. They will have a radiologic/imaging review if needed. They will be taught how to monitor their urine luteinizing hormone (LH) at home with an ovulation predictor kit. They will have their second study visit 9 days after their LH surge.

At visit 2, participants will take a urine pregnancy test. They will have a physical exam and have blood drawn. They will have a uterine lavage and endometrial biopsy. For this, a speculum will be placed into the vagina. A soft catheter will be inserted through the cervical canal into the uterus. Saline will be added into the uterus and then recovered after 30 seconds. A tissue sample will be taken.

About 46 days later, participants will start another round of LH monitoring. They will have a third study visit 9 days after their LH surge. At visit 3, they will repeat the tests from visit 2.

Some samples will be used for genetic tests.

Participation will last for 3 menstrual cycles.


Pregnancy loss is the most common complication of human gestation, occurring in roughly one-half of natural conceptions and most frequently in the first two to three weeks of gestation. In recent years it has become apparent that constitutive endometrial dysfunction represents an important contributor to infertility in women being treated with assisted reproductive technologies (ART). This application is specifically focused on the endometrial origins and basis of embryo implantation failure (EIF), early pregnancy failure (EPF), and recurrent pregnancy loss (RPL) in ART patients. The central hypothesis is that idiopathic infertility primarily stems from constitutive endometrial dysfunction, attributable to defects in progesterone responsiveness of the endometrial epithelium and stroma as well as immune cells. The goal of this research is to begin testing this hypothesis by focusing on infertile women experiencing the continuum of first trimester pregnancy loss. A team of exceptional extramural and intramural investigators with complementary and substantial expertise in basic reproductive biology and translational reproductive sciences will address that hypothesis by conducting a collaborative research project. At the NIH Clinical Center, the endometrium from cohorts of normal healthy fertile donors and infertile patients with carefully phenotyped and clinically-defined EIF, EPL or RPL will be biopsied in an outpatient setting (Aim 1). Advanced single cell technologies will be used to interrogate the endometrium (Aim 1). Organoids will be used to functionally study progesterone responses of the endometrial epithelium (Aim 2). In vitro decidualization will be used to functionally interrogate hormone responsiveness and decidualization capacity of the endometrial stroma and understand the influence of decidual immune cells (Aim 3). Cutting-edge genomic and transcriptomic technologies and advanced bioinformatics and data integration will be used to understand cell type heterogeneity, cell-specific differences in gene expression, and discern critical progesterone-driven biological pathways important for endometrial function that are disrupted in infertile women. The proposed aims are conceptually and technically innovative and together will have a broad impact on the field by filling a substantial gap in our fundamental knowledge of uterine biology and infertility. This application specifically targets NIH funding opportunity announcement PAR-18-951 entitled Opportunities for Collaborative Research at the NIH Clinical Center and focuses on major research priorities of the Fertility and Infertility Branch of the NICHD. These efforts will contribute to our understanding of the cellular basis of idiopathic infertility, enable the development of new tests enabling clinicians to diagnose and prescribe regimens directed at treating specific underlying endometrial dysfunction, and ultimately impact pregnancy outcomes in assisted and natural conceptions enabled by a personalized medicine approach.

Condition Normal Endometrial Physiology
Clinical Study IdentifierNCT04939064
SponsorEunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Last Modified on24 September 2021


Yes No Not Sure

Inclusion Criteria

In order to be eligible to participate in this study, an individual must meet
all of the following criteria
Stated willingness to comply with all study procedures and availability for the duration of the study
Female, aged 18-42, childbearing potential
In good general health as evidenced by medical history, previous fertility or diagnosed with infertility with and without a previous pregnancy loss
Normal Fertile - Control- Women with proven parity based on spontaneous conception without fertility treatment or prior diagnosis of infertility, normal uncomplicated pregnancy, and birth of at least one healthy baby
Early Implantation Failure (EIF) - Infertility defined by a failure to conceive
three or more failed transfers of high-quality blastocyst(s) (grade 3BB or higher); or b) two or more transfers of euploid blastocyst(s) (tested through trophectoderm biopsy and preimplantation genetic testing for aneuploidy (PGT- A) using next generation sequencing). These women will have a negative serum beta human chorionic gonadotropin (hCG) 12 days after ET
Early Pregnancy Failure (EPF) - Infertility defined by two or more biochemical pregnancies after transfer of a high-quality or euploid blastocyst with a positive hCG 12 days after ET but without subsequent clinical signs of pregnancy (detection of intrauterine or extrauterine gestational sac at 5-7 weeks of gestation). While, by definition these are pregnancies of unknown location (PUL) and will
include spontaneously resolving ectopic pregnancies, the vast majority of
these will be failed intrauterine pregnancies
\--Recurrent Pregnancy Loss (RPL): Infertility defined by the loss of two or
more pregnancies after transfer of a high-quality or euploid blastocyst with a
positive HCG 12 days after ET and subsequent clinical signs of pregnancy
(detection of an intrauterine gestational sac at 5-7 weeks gestation by

Exclusion Criteria

An individual who meets any of the following criteria will be excluded from
participation in this study
Women with prior hysterectomy as they do not have an endometrium
Postmenopausal women
Women with a history of preterm delivery (<37-week gestation), preeclampsia and/or stillbirth are excluded
Women with RPL must screen negative for the antiphospholipid syndrome (negative lupus anticoagulant, negative IgG and IgM antiphospholipid antibodies and negative IgG and IgM anti-2GP1 antibodies)
Women suffering from infertility with and without early pregnancy loss with prior diagnosis of common known disease risk factors, including disorders such as uterine anomalies, coagulopathy, balanced translocation, gynecological disease, other reproductive disorders and/or autoimmune conditions, pathology confirmed or suspected endometriosis, pathology confirmed or suspected adenomyosis, endometrial polyp(s) or submucosal fibroids, pathology confirmed acute or chronic endometritis, hydrosalpinx communicating with the endometrial cavity, history of Asherman syndrome, poorly controlled endocrinopathies, HIV infection, ovarian insufficiency and irregular menstrual cycles
Women who are currently Pregnant as we would not be able to obtain an endometrial sample
History of gonadotoxic therapy, precancerous (endometrial hyperplasia) or cancerous condition of the female reproductive tract
Current smoker or tobacco use or tobacco use within 30 days
Current use of reproductive hormones and/or fertility medications
Current use of steroids or non-steroidal anti-inflammatory agents within the last 3 days
Women who are obese (BMI >30)
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