Embryo transfer: Procedure and Precautions

embryo transfer
embryo transfer

Embryo Transfer

Your IVF procedure will take you through different steps. In vitro fertilization involves three essential components. It begins with induction of ovulation and subsequently fertilization of the oocyte with sperm. Finally, development of embryos is a crucial step followed by transfer into the uterus.

This IVF process is monitored by both the use of ultrasound and estradiol levels. Ultrasound indicates the number of oocytes that will be available for capture. Estradiol tells us about the quality of those oocytes.

What are the problems during embryo transfer?

Embryo transfer is routinely carried out using the transcervical route, which is basically a blind technique, associated with multiple potential negative factors that can result in total failure of the whole procedure. These potential negative factors include: (i) initiation of uterine contractility that may lead to an immediate or delayed expulsion of the embryos; (ii) the presence of cervical mucus that can plug the tip of the catheter or entangle the embryos and drag them out during withdrawal of the catheter; (iii) proper placement of the embryos into the uterine cavity may not be achieved due to failure to pass the catheter through the internal os. This can be due to acute utero–cervical angulation, cervical stenosis or anatomical distortion of the cervical canal.

What are the precautions taken during embryo transfer?

The technique of embryo transfer is very crucial and great attention and time should be given to this step. In order to optimize the embryo transfer technique, several precautions should be taken. The first and most important is to avoid the initiation of uterine contractility. This can be achieved by the use of soft catheters, gentle manipulation and by avoiding touching the fundus. Secondly, proper evaluation of the uterine cavity and utero–cervical angulation is also crucial. This can be achieved by performing dummy embryo transfer and by ultrasound evaluation of the utero–cervical angulation and uterine cavity length. Another important step is the removal of cervical mucus so that it does not stick to the catheter and inadvertently remove the embryo during catheter withdrawal. Finally, one has to be absolutely sure that the embryo transfer catheter has passed the internal cervical os and that the embryos are delivered gently inside the uterine cavity.

Key factors during embryo transfer

The key factors in achieving IVF success depends on the embryo transfer technique. Your doctor will focus on avoidance of uterine contractility during the embryo transfer. Before IVF proper evaluation of the uterine cavity is important. During embryo transfer removal of cervical mucus may add to success. Finally, proper insertion of catheter delivering the embryos inside the uterine cavity is crucial for IVF success.

What is single embryo transfer?

Single embryo transfer is a procedure in which one best embryo, is placed in the uterus. The embryo selected for transfer might be a cryopreserved embryos (frozen)) or from the current fresh IVF cycle. The remaining embryos may be set aside for future use or cryopreservation.

How long after embryo transfer does implantation occur?

IVF/ET involves four main steps:

  • retrieval of mature ova
  • fertilization of these mature ova in vitro
  • culture of preimplantation embryos and
  • embryo replacement within the uterus

To achieve a successful implantation, simultaneous development of blastocyst and the endometrium is essential. In Frozen embryo transfer the timing of blastocyst warming with endometrium is important. In a frozen embryo transfer cycle timing in a natural cycle is taken into consideration. Warming and transfer of a day 5 blastocyst is timed to 5 days after suspected ovulation. Even so, the optimal day of transfer in FET is not fixed.

In humans, implantation of a fertilised ovum is most likely to occur around 6 – 9 days after ovulation. The reception-ready phase of the endometrium of the uterus is usually termed the “implantation window” and lasts about 4 days.

Initially the newly hatched blastocyst loosely adheres to the endometrial epithelium. Then it rolls over the endometrium to find a suitable place for implantation where it gets attached firmly.

How does an embryo assessment work?

Embryo culture, assessment and selection are important steps in success of IVF treatment. An embryo is removed from an incubator for assessing under a light microscope. Its development is affected from exposure to ambient temperature and pH conditions. Embryos are evaluated and classified at the time of embryo assessment.  Classical criteria for assessing embryos include cell numbers, fragmentation rate and compaction status in cleavage embryo. Other criteria like nucleation status, cytoplasmic anomalies, spatial distribution of cells give us accurate results. Blastocysts are assessed by degree of expansion, inner cell mass morphology, and trophectoderm morphology.

Why Frozen embryo transfer is preferred in OHSS?

Controlled ovarian stimulation (COS) is an important part of IVF. It can induce the development of multiple follicles. Thus, COS produces higher levels of steroid hormones with the use of exogenous gonadotropin. Excessive stimulation of the ovaries can lead to life-threatening disease called ovarian hyperstimulation syndrome (OHSS). This condition doesn’t develop overnight. Your doctor does serial ultrasound to predict such a situation. Your hormone levels will also tell whether you are going towards COS. In this scenario, your embryo transfer is cancelled and embryos have to be cryopreserved. To avoid severe OHSS you must take enough vitamins and high protein diet during IVF treatment. This is an emergency condition and may need intensive care if severe.

Endometrial levels of natural killer cells and vascularization index in oocyte donors with stimulated cycles is more compared to natural cycles. Endometrial receptivity is altered under COS compared with natural cycle from the same patients. Hence it is preferable to go for frozen embryo transfer.

What makes embryo transfer successful?

Successful embryo implantation depends on high-quality embryos and good endometrial receptivity. Both fresh and frozen embryo transfer will need a good endometrium for implantation. Ovarian stimulation may be associated with poor endometrial vascularization. Hence many clinicians prefer frozen embryo transfer. Employing frozen thawed embryo transfer at the blastocyst stage are associated with an improvement in pregnancy rates.

Factors affecting success of embryo transfer are:

  • Protocol type
  • Gonadotrophin preparations
  • Frozen or fresh-cycle 
  • Endometrial thickness
  • The numbers of obtained oocytes, embryos
  • Quality of fresh or thawed embryos transferred

Is bed rest necessary after embryo transfer?

In the past days of IVF, women were instructed absolute bed rest for 15 days following an embryo transfer. In fact, patients were not even allowed to stand up for quite some time after the procedure. Instead, utmost care was taken for shifting patients and they were encouraged to use bed pan instead of going to toilet. Although IVF technology have evolved these rituals are still practiced at some fertility centres. In fact, this has taken its root as IVF culture.

Now that IVF has been around for over 3 decades, it is time to review how we advise patients going through treatment and reconsider whether bed rest is still advisable. The main reason for inactivity and bed rest was to divert blood flow to the uterus. But it has been found out that inactivity, combined with high levels of oestrogen can promote blood clot formation. These blood clots can obstruct blood flow to the embryo. By contrast, light exercise lowers stress hormone levels and promotes healthy blood flow. A study by Botta and Grudzinskas (1997) found that 24 h of bed rest after embryo transfer did not influence the pregnancy rate.

At Femelife Fertility we encourage a rest for 30 min after embryo transfer. But our studies show that immediate mobilization after an ET does not affect IVF success. Therefore, bed rest is not strictly recommended.

Does sleeping position affect implantation?

The answer is no, sleeping positions don’t affect implantation. In fact, patient should be encouraged to sleep peacefully and change positions according to her comfort.

How do I survive the 2 weeks wait IVF?

Two weeks of rest is advised after embryo transfer at almost all IVF clinics. During these days you need not be confined to bed, but avoid doing strenuous work. Light exercises and work from home is ideal during these days. Usually couples are under stress and negative thoughts during post embryo transfer days. You can plan to indulge in some creative works to avoid depression.

  • Read books of your choice like comics or novels
  • You can explore your talent in painting, singing etc
  • Cooking is another way of diverting thoughts.
  • You can listen to music at times, watch movies or TV series.
  • Crocheting or embroidery is another form of light work which can keep yourself engaged.

What should I avoid after the embryo transfer?

Few things are to be avoided after your embryo transfer which will be instructed at the IVF center. At Femelife Fertility we give a written note of guidance for couples after embryo transfer.

  • Avoid heavy exercises and strenuous work. Take rest and relax as much as possible.
  • Drink a lot of water and pass urine frequently. This can reduce the possibility of urinary tract infections.
  • Constipation may have adverse effects on implantation, so take more vegetables and fruits for a smooth bowel movement.
  • Take proteins, vegetables, and fruits. Avoid spicy and oily food, you may have stomach upset with these foods.
  • You preferably avoid having sex during these post embryo transfer days.
  • Avoid traveling long distances
  • Stop smoking and encourage your spouse to avoid smoking as well.
  • Avoid taking alcohol and sugary beverages.
  • Don’t take over the counter medications.

Prepare yourself for Embryo Transfer

Follow directions from your IVF clinic and prepare yourself for embryo transfer.

  • You will be on progesterone and other supportive medications after the embryo transfer. At some IVF centers progesterone is given as an oily injection which is painful. At times you may feel feverish after the injections.
  • Make sure you have enough medications for the next two weeks
  • Get domestic help so that you can take enough rest.
  • Keep the helpline number of the clinic ready for any emergencies. Inform about any bleeding, itching or vaginal discharge to the clinic.
  • Fever, cough, constipation, burning urine or any other ailment are also to be immediately notified.
  • Keep informed about early signs of pregnancy like implantation bleeding, profuse discharge or vomiting etc.
  • You may have to undergo certain tests following embryo transfer. Keep a note of it.

Embryo Transfer at Femelife Fertility

  • At Femelife Fertility we prepare the couple for embryo transfer much earlier.
  • Every patient undergoes mock transfer in the previous cycle. This tells us about any obstruction in the embryo transfer pathway.
  • Our IVF specialist evaluates your uterine cavity and makes sure you don’t have any polyp or fibroid in the cavity. In case you develop a polyp during stimulation your cycle will be cancelled and you have to wait for a frozen embryo transfer.
  • The fertility specialist decides about fresh or frozen transfer and keeps you informed during your IVF stimulation days.
  • We usually prefer a blastocyst transfer. Hence, we prepare our patients with progesterone for 5 days before embryo transfer.
  • The embryo transfer is done under ultrasound guidance at Femelife. So, come with a full bladder or otherwise, you may be waiting while your bladder fills up. A full bladder helps your doctor see the catheter clearly with trans-abdominal ultrasound for perfect placement of the embryo.
  • We don’t advise sedation or anaesthesia except for anxious patients. You can see the procedure in the ultrasound monitor while your doctor performs the procedure.
  • You will meet the embryologist who will discuss the quality of embryo(s) and answer questions. At Femelife fertility, we give a photo of the embryo taken the day of the transfer.
  • You will change your dress and wear a gown before going to the transfer room.
  • The transfer is done in the position of a gynaecological exam with feet in footrests and hips at the edge of the exam table.
  • You will meet the ultra-sonographer, who will do a trans-abdominal ultrasound to confirm excellent visualization. She will help you relax during the procedure.
  • The uterus lies beneath the bladder, and a full bladder provides a window through which the ultrasound waves can show a clear view of the uterine cavity.
  • Our staff will confirm your identity in the embryo transfer room to avoid confusion. The fertility nurse will clean the vagina and keep you draped with sterile sheets.
  • IVF specialist will clean your cervix and remove the thick mucous from your cervix. She may flush your cervical canal with culture media and keep the canal clean. She will introduce the embryo transfer catheter and position it at the cervix. At this stage you can see this catheter in the USG monitor.  This outer catheter will act as a guide to the inner catheter. The inner catheter is loaded with the embryos by the embryologist and brought to the transfer room. Now your doctor will push these embryos into your uterus and position it perfectly under ultrasound.
  • When the catheter is in the right spot and the embryo is placed, you can see a flash on the ultrasound screen within the uterine lining. The embryo is too small to see on the screen but you can see a small air bubble and media. This helps push the embryo through the catheter and place it safely in the uterus.
  • Your doctor will wait till the embryologists checks both the catheters and announces that the embryos are not detained.
  • Immediately after the embryo transfer you will be shifted to the room where you can lie down for 15 to 20 minutes before you can empty your bladder.

The embryo cannot fall out if you walk. Patients often prefer to relax a few minutes after the embryo transfer, but studies do show that the length of time lying down after the procedure does not impact success.

At Femelife clinic, we review medications and instructions, and then give the patient or couple a few minutes alone to reflect on the transfer.

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