Sequential Embryo Transfer (SET), Risks, Benefits, Success Rate

What is sequential embryo transfer?

Sequential embryo transfer (SET) is a fertility treatment that involves transferring embryos in a specific order and in separate stages to improve the chances of pregnancy. This method can help improve the chances of a successful pregnancy, particularly for women who have had previous failed IVF cycles or who have a history of miscarriage.

During SET, fertilized eggs are allowed to develop into blastocysts, which are then transferred in two separate cycles.

The first cycle typically involves transferring one or two embryos that have the highest chance of implanting successfully. The remaining embryos are then frozen and stored for use in a second cycle.
In the second cycle, any remaining viable embryos from the first cycle are thawed and transferred. This approach has been shown to increase pregnancy rates by up to 43% compared with traditional IVF methods.

While sequential embryo transfer may be more complex than traditional IVF treatments, its potential benefits make it an attractive option worth considering if you've struggled with infertility. It is an innovative and effective technique that offers hope to couples struggling with fertility issues regardless of their age or medical history.

Who needs a sequential embryo transfer procedure?

This process is useful for a variety of patients who have undergone assisted reproductive technologies such as IVF.

Women who have had multiple failed IVF attempts.
Women who are over 35 years old or
Women who have any underlying medical conditions, such as polycystic ovary syndrome (PCOS), endometriosis
Women with recurrent implantation failure (RIF) can also opt for this method.

Note: RIF occurs when there is no successful implantation after multiple transfers. With SET, doctors can better evaluate which embryos are more viable by observing how they develop over time before transferring them into the uterus.

Alert: Not all women are candidates for sequential embryo transfer due to underlying health conditions or other factors. Your doctor will evaluate your situation and make recommendations based on your specific needs and goals.

Risks and Benefits

What are the side effects of sequential embryo transfer?

While sequential embryo transfer can be an effective way to increase the chances of a successful pregnancy, there are potential side effects that should be considered.

Cramping: mild cramping or discomfort during the procedure, which is typically performed under local anaesthesia.
Infection: There is always a small risk of infection associated with any medical procedure. However, your doctor will take steps to minimize this risk by ensuring that all equipment and materials are sterile and that you receive antibiotics if necessary.
Multiple Pregnancies: Because more than one embryo may be transferred during sequential embryo transfer, there is an increased likelihood of twins or triplets. While some couples welcome the prospect of having multiples, others may find it challenging to care for more than one infant at a time.

While there are potential risks associated with sequential embryo transfer, many couples find it to be a safe and effective option for achieving their dreams of starting or expanding their family.

What are the benefits of sequential embryo transfer?

It offers several benefits over traditional IVF methods.

Healthy embryos: Sequential embryo transfer allows the embryologist to evaluate the embryos more closely before implantation. In this way, only the healthiest embryos are transferred into the uterus.
Reduces effect of previous miscarriages: Secondly, sequential embryo transfer provides a higher chance of pregnancy success for women who have experienced recurrent miscarriages or have age-related infertility problems. This is because two transfers of fresh and frozen embryos increase the chances of viable pregnancies in such cases.
Avoids genetic abnormalities: SET is an effective alternative method for those whose previous treatments failed or those at high risk of genetic abnormalities from natural conception.

What is the success rate of sequential embryo transfer?

The implantation rate in sequential embryo transfer is about 25-40%.

Procedure Details

How much time does the sequential embryo transfer process require?

The length of the sequential embryo transfer procedure depends on several factors. Firstly, it may vary depending on the patient's menstrual cycle and when ovulation occurs. Typically, the procedure takes place between days 14 to 18 of a woman's monthly cycle.

How long does it take to conceive with sequential embryo procedure?

It's important to note that conception may not occur immediately following the sequential embryo transfer procedure. Each patient's situation is unique, and factors such as age, overall health, and previous fertility treatments can all impact how long it takes to conceive. Generally it takes 10 days for successful implantation and pregnancy to be detected.

How is the sequential embryo transfer performed?

The procedure for sequential embryo transfer is a bit more complex than traditional embryo transfer. It involves two separate transfers, each timed to work with the woman's natural cycle.

Firstly, the woman will undergo ovarian stimulation to produce multiple eggs. These eggs are then fertilized in vitro and allowed to develop into embryos over several days.
In traditional embryo transfer, one or two of these embryos would be implanted directly into the uterus. However, with sequential embryo transfer, the first set of embryos is frozen while the second set continues developing until they reach the blastocyst stage.
The woman's uterine lining is then prepared for implantation before thawing and transferring the first set of embryos. If this results in a failed pregnancy or miscarriage, there is still a chance for success with the second set of embryos that were allowed to continue developing.

Key Takeaway:

Sequential embryo transfer (SET) is a fertility treatment that involves transferring embryos in a specific order to improve the chances of pregnancy.
During SET, fertilized eggs are allowed to develop into blastocysts, which are then transferred in two separate cycles.
The first cycle involves transferring one or two embryos that have the highest chance of implanting successfully.
The remaining embryos are then frozen and stored for use in a second cycle.
Women who have had multiple failed IVF attempts, those with underlying medical conditions, and women with recurrent implantation failure (RIF) are good candidates for this procedure.
However, there are potential side effects, such as mild cramping and multiple pregnancies.
The procedure takes approximately three weeks in total, and conception may not occur immediately.

Frequently asked questions

Is it better to transfer 1 or 2 embryos?
Which cycle of IVF is most successful?
Which month is best for IVF?

Reference

Dr Purva Singh

MBBS MS OBGYN
IVF Specialist