Not yet recruitingOBSERVATIONAL

Endometrial Immune Profile in Recurrent Implantation Failure

This study aims to understand why some women experience 'recurrent implantation failure' (RIF), meaning they don't get pregnant despite several IVF attempts with good-quality embryos. Researchers believe there might be differences in the immune cells found in the lining of the womb (uterus). They are comparing womb lining tissue and blood samples from women with RIF to those who have had at least one natural, healthy pregnancy. By studying these immune cells, including types like natural killer cells, macrophages, and T cells, the team hopes to find specific patterns or differences. This information could eventually lead to new treatments that help more women successfully get pregnant after IVF.

At a glance

Status

Not yet recruiting

Sponsor

King's College London

Enrolment target

Start

01 Oct 2026

Estimated completion

01 Dec 2028

Recurrent Implantation Failure Infertility (IVF Patients)

What is this study about?

This study is looking into a common and often upsetting problem called 'recurrent implantation failure' (RIF). This is when a woman has tried IVF several times with what seem to be good embryos, but they haven't been able to get pregnant. It can be very frustrating because doctors don't always know why it happens. The study wants to find out if the body's immune system, specifically the immune cells in the lining of the womb (called the endometrium), might play a part.

Our immune system helps protect us from illness, but it also has a role in pregnancy. It needs to be balanced – strong enough to protect the mother, but also gentle enough not to reject the embryo. This research will compare the immune cells in the womb lining of women who have experienced RIF to those who have had a healthy pregnancy without any fertility problems. They will look at different types of immune cells, how many there are, and what they are doing.

The main goal is to see if there are clear differences in these immune cells between the two groups. By understanding these differences better, the researchers hope to uncover new reasons why some embryos don't settle into the womb. This knowledge could then help doctors develop better tests or treatments in the future to improve the chances of pregnancy for women undergoing IVF.

Key takeaways

The study investigates why some women don't get pregnant after IVF.
It compares immune cells in the womb lining of women with fertility issues to those who've had healthy pregnancies.
The aim is to find new reasons for implantation failure and improve future treatments.
Participation involves a consultation, cycle tracking, a womb tissue sample, and a blood test.
It will not directly help you get pregnant, but may help future patients.

Who may be eligible?

This study is looking for two groups of women, both aged between 18 and 40.

One group is for women who have experienced 'recurrent implantation failure' (RIF). This means you've had several IVF attempts with good embryos, but haven't become pregnant, and doctors haven't found a clear reason why. You should have regular monthly periods, be generally healthy, and have a healthy body mass index (BMI under 30). You also shouldn't have conditions like endometriosis, significant womb problems (like large fibroids), or recent infections or treatments that could affect your immune system or womb.

The other group is for 'control' women who have had at least one healthy pregnancy that resulted in a live birth. You should also have regular periods, be generally healthy, and have a BMI under 30. You should have given birth at least a year ago and not be currently pregnant or breastfeeding. Neither group should be actively trying to get pregnant during the study, have blood disorders, or be unable to provide informed consent in English.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you a woman between 18 and 40 years old?
Do you have regular monthly periods?
Do you have a healthy Body Mass Index (BMI under 30)?
Have you experienced several failed IVF attempts with good embryos (RIF group)? OR Have you had at least one healthy pregnancy and live birth (Control group)?
Are you generally healthy, without significant medical conditions or recent infections?
Are you NOT currently pregnant, breastfeeding (if in control group), or actively trying to conceive during the study cycle (if in RIF group)?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll first have a meeting (which can be online) to discuss the study in detail and make sure you understand everything. If you agree, you'll need to confirm the timing of your monthly cycle using home ovulation tests, and possibly an ultrasound scan and a blood test.

Then, at a specific point in your cycle (when your womb lining would normally be ready for an embryo), you will have two quick procedures: a small tissue sample taken from the lining of your womb (this is called an endometrial biopsy) and a blood sample taken from your arm. You might also have a quick internal ultrasound scan if you haven't had one recently. The study involves a few appointments, but the main tissue and blood samples are taken during one visit. The total duration of your active involvement in the study will be relatively short, focused around identifying your cycle and taking these samples.

Potential risks and benefits

Taking part in this study won't directly help you get pregnant, but it could help other women in the future by improving our understanding of fertility problems. The main risks are minor discomfort or a small chance of infection from the womb biopsy and blood test. You might also feel a bit anxious about the procedures. You are free to change your mind and leave the study at any time, for any reason, without it affecting your care.

Locations (1)

King's Fertility
Verified postcode
London, United Kingdom

Common questions

What is 'recurrent implantation failure' (RIF)?

RIF is when you haven't become pregnant after several IVF attempts, even with good embryos, and doctors can't find a clear reason why.

Will this study help me get pregnant?

No, this study is for research purposes only and won't directly help you get pregnant. The aim is to help improve future treatments for others.

What happens during the womb tissue sample?

A very thin tube is passed through your cervix to gently take a tiny piece of tissue from the lining of your womb. It can feel like a strong period cramp but usually doesn't last long.

How long will I need to be involved in the study?

Your active involvement will focus on understanding your cycle and having a single visit for the samples. It's not a long-term commitment.

Do I need to stop trying to conceive if I join?

Yes, if you're in the RIF group, you shouldn't be actively trying to conceive during the month you provide samples for the study.

How to find out more

Nicole Ryan, MBBCh, MRCOG

nicole.ryan@kingsfertility.co.uk 020 3957 7950 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.