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Letrozole During IVF/ICSI for Women with Endometriosis

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is being done in women with endometriosis who are undergoing IVF/ICSI, which are fertility treatments using eggs, sperm, and embryos outside the body. The treatment being studied is letrozole, a medicine taken by mouth during ovarian stimulation, the part of treatment when the ovaries are helped to produce eggs. The purpose of the study is to find out whether adding letrozole during this part of treatment can improve the chance of a live birth after embryo transfer.

In the study, one group receives letrozole together with the usual fertility treatment, while the other group receives the usual treatment without letrozole. Treatment is given during one egg collection cycle, and any embryos made from that cycle may be transferred fresh or frozen and used later within about one year. The study then follows the pregnancy outcomes after these embryo transfers. The study also looks at related conditions such as adenomyosis, a condition in which tissue similar to the lining of the womb grows into the womb muscle.

The study is designed to see whether letrozole can improve reproductive results in this setting and to collect information on pregnancy, birth, and any problems that may happen during pregnancy. It also records pain after egg collection and quality of life around the time of embryo transfer.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

Step 1
Randomization and start of treatment
After you join the study, you are assigned at random to one of the study groups. In one group, you take letrozole by mouth during ovarian stimulation. Ovarian stimulation means treatment used to help the ovaries produce eggs for in vitro fertilization or intracytoplasmic sperm injection.
The study medicine is letrozole 5 mg, taken once daily by oral use for the full period of ovarian stimulation.
Step 2
Ovarian stimulation and egg collection
You continue the assigned treatment during the ovarian stimulation phase. The study description does not give a longer treatment schedule beyond this phase.
When the ovaries have been stimulated, oocyte aspiration is performed. Oocyte aspiration means that eggs are collected from the ovaries.
Step 3
Embryo transfer after egg collection
After egg collection, an embryo transfer may take place. Embryo transfer means placing an embryo into the uterus.
A fresh embryo transfer may occur first. If embryos are not transferred right away, frozen embryo transfers from the same egg collection may also take place later.
Step 4
Follow-up during the first year after randomization
The study follows the results of the same egg collection for up to 1 year after randomization.
During this period, the study checks for live birth after fresh and frozen embryo transfers from the same stimulation cycle.
Step 5
Outcome checks after transfer
After embryo transfer, the study checks whether pregnancy has started by measuring beta-hcg in blood. Beta-hcg is a pregnancy hormone measured 10 to 15 days after transfer.
The study checks for a clinical pregnancy by ultrasound 4 to 6 weeks after transfer. Clinical pregnancy means that at least one gestational sac is seen on ultrasound.
The study records whether there is a miscarriage, which means pregnancy loss before the pregnancy is considered viable.
The study also records whether there is an ectopic pregnancy, which means a pregnancy outside the uterus, or a pregnancy of unknown location, which means the pregnancy cannot yet be placed in the uterus or elsewhere.
Step 6
Pregnancy and birth follow-up if pregnancy continues
If your pregnancy continues beyond 24 weeks, the study records pregnancy and birth outcomes.
These include pre-eclampsia, which is high blood pressure during pregnancy with signs of organ stress, pregnancy-induced hypertension, which is high blood pressure that starts during pregnancy, preterm birth, intrauterine growth restriction, which means the baby grows more slowly than expected, caesarean delivery, and obstetric hemorrhage, which means heavy bleeding around childbirth.
The study also records extreme preterm birth between 24 and 28 weeks of pregnancy, stillbirth, termination of pregnancy, gestational age at delivery, birthweight, neonatal admission, neonatal mortality, and major congenital abnormalities, which are serious birth defects.
Step 7
Pain and quality of life checks
The study measures your pain using a scale from 1 to 10 1 to 4 hours after oocyte aspiration.
The study measures your quality of life on the day of fresh embryo transfer, which is described as opu + 5. OPU means oocyte aspiration, and +5 means 5 days after that procedure.
Your quality of life is compared with the level recorded at the start of the study.

Who can join the trial?

10 criteria

Women who are subfertile or infertile, meaning they have difficulty becoming pregnant, and who have a diagnosis of endometriosis of any type or stage.
The diagnosis of endometriosis must have been made by transvaginal ultrasound (TVUS), MRI (magnetic resonance imaging), or surgery.
They must already have a medical reason to undergo IVF/ICSI, which are fertility treatments where eggs are collected and fertilized outside the body, with ICSI meaning a single sperm is injected directly into an egg.
A fresh embryo transfer must be planned after egg retrieval, meaning an embryo will be placed into the uterus soon after the eggs are collected.
Women with or without adenomyosis may take part; adenomyosis means tissue similar to the lining of the uterus grows into the muscle wall of the uterus.
They must have had no more than three consecutive unsuccessful IVF/ICSI cycles since the last ongoing pregnancy, including attempts that led to fresh or frozen embryo transfers.
They must be between 18 and 39 years old.
Their body mass index (BMI) must be less than 35 kg/m²; BMI is a measure of body weight compared with height.
They must be able to give informed consent, meaning they can understand the study and agree to join it on their own.
Each patient can take part in the study only once.

Who cannot join the trial?

7 criteria

Anti-Müllerian hormone (AMH) level below 0.5 ng/mL in the year before randomization. AMH is a blood test that helps estimate ovarian reserve, meaning how many eggs may remain in the ovaries.
An abnormal uterine cavity, such as a Müllerian duct anomaly (a birth-related difference in the shape of the uterus), intra-uterine adhesions (scar tissue inside the uterus), or any other untreated problem inside the uterus.
Untreated tubal factor, specifically hydrosalpinx. Hydrosalpinx means a fallopian tube is blocked and filled with fluid.
Any untreated endocrine abnormality. Endocrine means hormone-related, so this includes any hormone problem that has not been treated.
If sperm must be obtained by surgery, which means surgically obtained sperm.
If ovarian stimulation is being done for pre-implantation genetic testing (PGT-A/M). This is testing embryos for chromosome problems or specific genetic diseases before transfer.
A history of severe ovarian hyperstimulation syndrome (OHSS) in a previous treatment cycle, or if the patient is already planned to follow a freeze-all strategy. OHSS is a serious reaction where the ovaries become overstimulated during fertility treatment; a freeze-all strategy means all embryos are frozen instead of being transferred right away.

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Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Cliniques Universitaires Saint-Luc
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Woluwe-Saint-Lambert, Belgium
Katholieke Universiteit te Leuven
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Leuven, Belgium
Universitair Ziekenhuis Gent
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Gent, Belgium

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Investigated drugs

Letrozole is the study medicine being tested in this trial. It is taken by mouth during ovarian stimulation as part of IVF/ICSI treatment. The goal is to see whether adding letrozole can help improve the chance of a live birth after embryo transfer in women with endometriosis, with or without adenomyosis. It is being used alongside the usual fertility treatment, not as a stand-alone treatment.

Letrozole

What is already known about the treatment

Letrozole - Letrozole is taken by mouth as a film-coated tablet, usually swallowed with water, and in this trial it is used together with ovarian stimulation during IVF/ICSI. It is a well-known medicine in medical practice and medical literature, mainly used to treat certain hormone-sensitive breast cancers, and it is also used in fertility care in some settings. Letrozole is a type of aromatase inhibitor, which means it blocks the enzyme that helps the body make estrogen, lowering estrogen levels and changing the hormone balance in a way that can support egg development.

Investigated diseases

Endometriosis - Endometriosis is a condition in which tissue similar to the lining inside the uterus grows outside the uterus. It often causes ongoing pelvic pain and may be linked to heavy or painful periods. The tissue can respond to monthly hormone changes, so symptoms may come and go over time. In some people, it can lead to scarring and changes in nearby organs.