Implantation Failure in IVF – Why Does It Happen?


Today, around 50 million couples worldwide have fertility issues and are incapable of conceiving naturally. With advancements in science and healthcare, procedures like IVF, ICSI, IUI, etc., are helping such couples fulfill their dreams of parenthood.

Now, as per the success rate of IVF, i.e 40-50%, not all cycles result in pregnancy. There could be multiple reasons for IVF failure, one of which is Implantation Failure.

Even when all the initial procedure steps go well, and the embryo looks picture perfect, there are slight chances that the embryo doesn’t implant.

This blog is for all going through IVF or planning to consider it in the future. It is always best to stay informed about your treatments to do your best part.

What is Implantation Failure in IVF?

Before understanding implant failure, let’s give you some basic information about implantation’s meaning.

In a natural pregnancy, the egg and sperm fuse in a fallopian tube to form an embryo. The embryo cells divide and reach the uterus in the blastocyst stage. Next, successful attachment of the embryo to the uterine wall (known as implantation) results in pregnancy.

On the other hand, during IVF treatment, an egg and sperm are left in a petri dish overnight to fuse and form an embryo. On day five, this embryo (at the blastocyst stage) is transferred to the women’s uterus, which is called embryo transfer. At last, when the embryo attaches itself to the endometrium, the pregnancy begins.

Sometimes for various reasons, embryos don’t implant and hamper a pregnancy. When this happens in multiple IVF cycles, it is medically termed Recurrent Implantation Failure (RIF).

There could be two logical reasons behind implantation failure; a genetically defective embryo or a non-receptive uterus (one that doesn’t allow an embryo to attach).

Before talking about the reasons behind implantation failure, it’s essential to understand the symptoms of failed implantation.

Symptoms of Failed Implantation [signs of failed ivf (in 2ww)]

In IVF, there is about a two-week wait (2ww) between embryo transfer and a pregnancy test. 

After undergoing in vitro fertilisation (IVF), changes in a woman’s body may occur due to implantation. These changes may include an altered sense of smell, increased breast sensitivity, and mild abdominal cramping. If these symptoms are absent even after a few weeks post-IVF, it could indicate a failure.

On the other hand, vaginal bleeding could be a warning sign of an ectopic pregnancy, which happens when a fertilised egg implants in one of the fallopian tubes instead of the uterus lining. This condition may cause abdominal and pelvic pain, and in severe cases, shoulder pain.

Signs of Failed Ivf (in 2ww)

  1. Cramps
  2. Nausea
  3. Headache
  4. Back Pain

There is also a possibility that vaginal bleeding may be a sign of an ectopic pregnancy. In this case, a fertilized egg implants into a fallopian tube rather than the uterine lining.

To be sure about successful implantation, you will have to wait and get a pregnancy test done. You can take an at-home pregnancy test or visit a clinic for a blood test.

Two week wait (2ww) in IVF

During IVF (in vitro fertilization), the two-week wait (2WW) occurs between embryo transfer and pregnancy test. To help you understand the 2WW in IVF, here are some key points:

  • The 2ww is a critical time for IVF patients, as they anxiously wait to find out if the treatment has been successful.
  • During the 2ww, patients are typically advised to rest and avoid strenuous activity to give the embryos the best chance of implanting in the uterus.
  • Patients may experience various physical and emotional symptoms during the 2ww, such as cramping, bloating, mood swings, and anxiety.
  • It’s important for patients to follow their doctor’s instructions and take any prescribed medications during the 2ww to support the pregnancy.
  • Patients should avoid doing a home pregnancy test during the 2ww, as it may not provide accurate results and can cause unnecessary stress and anxiety.
  • The pregnancy test is usually scheduled for about 10–14 days after the embryo transfer, depending on the clinic’s protocol.
  • If the pregnancy test is positive, the patient will typically continue receiving care from their IVF clinic until they are released to their regular OB/GYN.
  • If the pregnancy test is negative, the patient and their doctor will discuss next steps, which may include trying another IVF cycle or exploring other fertility treatment options.

Reasons behind Failure of Blastocyst Implantation

Let’s now quickly jump on the implantation failure reasons.

Even when all the things are taken care of, there are chances that an embryo doesn’t attach to the uterine wall. Medical experts say that they don’t fully understand why this happens, but there are some possible causes of implantation failure, such as:

  • Female anatomic factors such as congenital uterine abnormalities, uterine fibroids, hydrosalpinges, adhesions, endometrial polyps, endometriosis, etc., can cause recurrent implantation failure (RIF).
  • Contrarily, severe oligoasthenozoo-spermia (low sperm count) or increased sperm DNA fragmentation in a male partner can cause issues.
  • Genetic or chromosomal abnormalities in an embryo don’t allow it to implant in the uterus.
  • Other health issues like thyroid, diabetes, infection, etc., can affect your pregnancy chances.
  • Psychological factors and poor lifestyle can also affect your implantation success.

Apart from the above factors, there can be other reasons behind RIF. Let’s understand the role of endometrium in implantation.

What happens when the blastocyst does not implant?

The embryo cannot grow if it does not implant, so you can’t conceive. During the development of the blastocyst, the lining of the uterus (the endometrium) undergoes several internal changes to prepare to connect the blastocyst to it.

It would be impossible for implantation to take place without these changes, and the embryo would shed during menstruation.

An ectopic pregnancy occurs when the zygote implants outside the uterus. Studies show that blastocyst implantation failure rates can be as low as 30%. The fertility specialist may suggest preimplantation genetic screening (PGS) if your previous IVF cycle failed.

To determine the correct number of chromosomes in an embryo, PGS tests a few cells. A 98% accuracy rate can be achieved by PGD for detecting single-gene disorders in embryos.

Role of Endometrium in Implantation

The endometrium is a blood tissue that lines the inside of the uterus. In every menstrual cycle, this endometrium layer builds up and prepares to support a baby’s growth. When fertilization doesn’t happen, this layer sheds in the form of blood, known as periods.

On the other hand, when fertilization happens, and the embryo comes down to the uterus on day 5, it interacts with the endometrium layer and attaches itself to support the fetus.

It is essential to understand that this endometrium layer is not always ready. The phase where an endometrium layer is most receptive is between the 20-24th days of a menstrual cycle, known as the “implantation window.”

To consider this appropriate timing, embryo or blastocyst transfer is done accordingly to match the natural implantation window. There is no definite way of checking whether the endometrium is receptive. However, doctors use ultrasounds to measure the thickness of the endometrium layer.

Suppose all of these things are taken care of. In that case, there is a high chance that embryo/blastocyst transfer done during the window of implantation will result in pregnancy.

But what if somebody’s endometrium is non-receptive?

Some factors indirectly affect the receptivity of endometrium, such as:

  • Fibroids, adhesions, or polyps
  • The thin lining of the endometrium (less than 8 mm)
  • Uterine infection

Moreover, there could be other unproved reasons why endometrium can be non-receptive.

Implantation Failure Treatment: Is it possible?

Yes, the treatment of implantation failure is possible if the cause or reason is known. For example, suppose the cause is related to genetic abnormalities. In that case, you can do some tests to rule out chromosomal issues before transferring the embryo.

In other cases where health issues like fibroids, polyps, or adhesions hamper implantation, doctors decide to remove them.

Secondly, in cases with advanced maternal age or low ovarian reserve, the chances of pregnancy become very low. In this case, it is important to accept that women might need to use donor eggs, and the baby will not be their genetic baby.

At last, women with thin endometrium layers might face difficulties in implantation. However, there are still many women who conceive with thin endometrium.

Suppose you are someone who is experiencing recurrent implantation failure. In that case, the best treatment depends upon finding and treating the cause. For this, please consult with your doctor.


Recurrent Implantation failure can be stressful when couples go through an IVF cycle. However, if we take extra measures and know the cause, there are chances we can treat it.

If you are facing issues regarding implantation, it is best to consult a specialist.


After a successful embryo transfer, your body will undergo changes resulting in symptoms. These symptoms include:

  1. Cramping
  2. Spotting
  3. Nausea
  4. Vomiting
  5. Tiredness
  6. Fatigue
  7. Sore breast
  8. Missed periods
  9. Frequent urination
  10. Bloating

Yes, experiencing no symptoms after embryo transfer is normal. Around 10% of women do not experience any symptoms but get a positive pregnancy test. So, if you don’t experience any pregnancy symptoms, there are still chances you are pregnant.

Do not stop taking your medicine without talking to your doctor, as many women have bleeding during pregnancy. To confirm, a doctor has to do a beta-hCG blood test, so better consult a doctor.

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