Frozen Embryo Transfer (FET): Tips, Timeline & Process

Frozen Embryo Transfer (FET) is a form of assisted reproductive technology that has become increasingly popular recently. It involves the transfer of previously frozen embryos to a woman's uterus, often as part of an IVF treatment cycle. FET offers several benefits over fresh embryo transfer, including increased flexibility in timing and improved success rates.

In this article, we will explore the process of Frozen Embryo Transfer, including tips for preparing for the procedure, the frozen embryo transfer timeline, and what to expect during the transfer itself. We will also discuss the factors affecting the frozen embryo transfer success rate and provide advice for optimizing your chances of achieving a successful pregnancy. Whether you are considering FET as part of your infertility treatment or want to learn more about this innovative technology, this article will provide you with the information you need to make informed decisions about your reproductive health.

Read more: Embryo Freezing: Process Timeline & Success Rate

Frozen vs. Fresh Embryo Transfer

Frozen embryo transfer (FET) and fresh embryo transfer are both viable options for in vitro fertilization (IVF), with their advantages and disadvantages. 

While fresh embryos may be recommended for younger patients without chromosomal issues or for older patients with embryos that may have a better chance in utero, FET allows for genetic testing and eliminates the risk of ovarian hyperstimulation syndrome (OHSS). 

Research has shown that success rates are nearly identical for both options, with some studies even showing a slightly higher accumulative live birth rate for FET under certain circumstances. Some doctors may recommend an elective FET approach, where all embryos are cryopreserved and transferred in a later cycle. Cryopreservation provides a viable way to store and preserve embryos for future use.

Frozen Embryo Transfer Procedure

Why Choose Frozen Embryo Transfer?

For several reasons, someone may choose frozen embryo transfer (FET) over fresh embryo transfer. Some of these reasons include:

  • Better timing: With FET, the timing of the embryo transfer can be more carefully controlled and coordinated with the woman's menstrual cycle, which can increase the chances of a successful pregnancy.
  • Higher success rates: Studies have shown that FET may result in higher success rates compared to fresh embryo transfer, particularly for women who have had multiple unsuccessful cycles of in vitro fertilization (IVF).
  • Reduced risk of ovarian hyperstimulation syndrome (OHSS): OHSS is a potential complication of IVF that can occur when a woman's ovaries are overstimulated. By using frozen embryos, the risk of OHSS is reduced because the woman does not need to undergo ovarian stimulation.
  • Increased flexibility: FET allows for greater flexibility in scheduling and planning, as the embryos can be stored for later use if needed.
  • Improved genetic testing: With FET, embryos can be genetically tested before transfer, which can help identify any potential genetic abnormalities and increase the chances of a successful pregnancy.

Preparing for Frozen Embryo Transfer

Frozen embryo transfer is not a complicated procedure, but before the operation, consider the following tips:

  • Take your medications, especially the hormonal ones, as they were prescribed;
  • Take an ultrasound scan to check the condition of the ovaries and uterus;
  • Purchase warm socks. Warmth promotes blood flow and circulation, which may benefit implantation. Wear comfortable slip-on shoes and warm socks on the day of your FET.
  • Get plenty of sleep before and after the transfer. Aim for 7-8 hours of sleep each night. Adequate sleep supports fertility and overall health.
  • If you have a history of miscarriage or premature birth, inform your doctor;
  • Avoid having sexual intercourse for three days before the transfer;
  • Reduce your screen time for a couple of days before frozen embryo transfer (FET);
  • Have a nutrient diet rich in omega-3 fatty acids, whole grains, legumes, healthy fats, lean proteins, and fresh fruits and vegetables, and avoid cold foods, processed foods, sugar, and caffeine that may irritate your digestive system;
  • Avoid exposure to harmful chemicals and radiation;
  • Avoid extreme temperatures against your abdomen and uterus. Keep your laptop away from your body and avoid saunas or hot tubs.
  • Stay hydrated;
  • Eat a healthy breakfast on the day of embryo transfer; 
  • Come to your embryo transfer with a full bladder. This helps your doctor see the catheter more clearly for embryo placement.

What to Do the Night Before Embryo Transfer?

Embryo transfer is one of the most important steps of the IVF cycle, so you should be well-prepared for it. In order to increase the chance of IVF success, consider the following tips the night before embryo transfer:

  • Take a shower; 
  • Avoid doing strenuous activities and get plenty of rest;
  • Relax your body and mind by doing yoga and meditation;
  • Ask your doctor if you should take any medication (including progesterone);
  • Do not wear strong perfumes, as embryos are sensitive;
  • Ask someone to be your caregiver; 
  • Ask your doctor if your bladder should be full for transfer;
  • Avoid having sex.

Diet Before Embryo Transfer
Read more: The Best Diet Before Embryo Transfer to Increase Fertility Chances.

Frozen Embryo Transfer: How to Prepare

Frozen Embryo Transfer Procedure Step-by-Step

FET is a two-phase process that begins with carefully preparing the uterine lining, ensuring a receptive environment for embryo implantation. This involves a Hormone replacement therapy (HRT) cycle to stimulate the growth of a thin, healthy endometrium, similar to the early stages of a natural menstrual cycle. 

Frozen embryo transfer is a rather simple procedure that does not require anesthesia. This operation is done in a fertility clinic or hospital and takes almost 15 minutes. On the day of the transfer, the doctor will perform an ultrasound scan on your uterus to check the condition of your endometrium. If everything is good, the process of embryo transfer begins.

After the initial preparation and rinsing of the discharges from the vagina, the IVF specialist transfers one or more embryos to the uterine cavity by a fine tube called a catheter. After the transfer, you have to lie down for 20 minutes, and then you can go back home.

To confirm the pregnancy, you can take a blood or urine test almost two weeks after the frozen embryo transfer. Although taking a pregnancy test sooner might be tempting, specialists highly recommend waiting at least 15 days before the beta test.

What to Do after IVF with Frozen Embryo to Increase Success?

After IVF with a frozen embryo, take the following care:

  • Take all the prescribed medications as before. Do not increase or taper off any medication at your discretion;
  • Take a pregnancy test 15-18 days after frozen embryo transfer (FET). If the test is negative, repeat 48 hours later, and if it is positive, continue taking the medication as usual and visit your doctor as soon as possible;
  • Rest at home for up to three days and ask someone to be your caregiver;
  • If you have a history of chronic cough or constipation, inform your doctor;
  • Do pregnancy exercises;
  • After transferring the embryo, you can take quick showers, but you shouldn't stay in a hot bathroom for too long;
  • After the transfer, you can have all kinds of foods except canned and processed ones, herbal teas, and alcoholic beverages. Add more fruits and vegetables to prevent constipation for a proper diet after embryo transfer.
  • You can sleep in any position you feel comfortable, and it is not necessary to put your legs up while sleeping; 
  • Maintain vaginal hygiene;
  • In case of spotting, bleeding, shortness of breath, or severe abdominal pain, contact your doctor immediately.
Add more fruits and vegetables to your diet after frozen rmbryo transfer.

Things to Avoid After Frozen Embryo Transfer

  • Avoid strenuous activities and sexual intercourse until your pregnancy is confirmed;
  • Avoid straining during bowel movements;
  • Avoid contact with people with colds, rubella, chicken pox, or the flu;
  • Avoid wearing makeup and perfume, as the embryos are sensitive to chemicals;
  • Avoid hot baths, swimming, spas, and saunas for two weeks;
  • Avoid long road trips;
  • Avoid stress and anxiety, and
  • Do not take non-prescribed medicine without consulting your doctor.

How to Increase Your Chances of IVF Success
Read more: How to Increase Chances of Successful IVF?

Frozen Embryo Transfer Timeline

Each cycle of frozen embryo transfer will take almost three to four weeks. You must take birth control pills for about two weeks to restrain ovary activity. When the ovary is suppressed completely, it is time to check the hormone levels and endometrium. To that end, you must perform a transvaginal ultrasound scan and necessary blood work on days 2-4 of your menstrual cycle. 

Based on the condition of your uterus, the doctor prescribes the estrogen injection. Usually, the patients have to inject estrogen for a week to thicken the uterus lining and prevent ovarian follicles from growing. After estrogen injections, another bloodwork and transvaginal ultrasound are needed to check the uterus lining. 

If your endometrium has the expected lining, i.e., 7mm, your doctor will ask you to take daily injections or vaginal suppositories of progesterone for four to five days.

Finally, you are ready for embryo transfer almost two weeks after taking birth control pills. Your doctor will determine the exact day of the transfer. On that day, you go to a fertility clinic with a full bladder and receive the fertilized egg through a simple procedure. As doctors suggest, the embryo will be implanted within 24-48 hours after the transfer, but you must wait 15 days before taking the pregnancy test. 

Frozen Embryo Transfer timeline

Why Do People Freeze Embryo?

For various reasons, couples may freeze and store their embryos to use them in the future. Some of these reasons include:

  • Low level of anti-Mullerian hormone (AMH), which makes the ovaries produce fewer eggs;
  • Having cancer. Some couples prefer to freeze their embryo before undergoing chemotherapy or radiotherapy; 
  • Intending to have children in the distant future, even during the menopause period; 
  • Having polycystic ovary syndrome (PCOS), which causes hormonal imbalance in women and reduces their ovaries reserve;
  • Having menstrual disorders and
  • intend to have more kids in the future by using the IVF method. 
  • Also, in some rare cases, people freeze their fertilized eggs to sell them to infertile couples in the future. 

For a variety of reasons, couples may freeze and store their embryos to use them in the future.

Side Effects of Frozen Embryo Transfer

In some cases, frozen embryo transfer may have temporary side effects such as: 

  • Pain in ovaries;
  • Cramping;
  • Swelling of the ovaries;
  • Mild lower abdominal pain;
  • Bloating and diarrhea;
  • Nausea and vomiting;
  • Accumulation of fluid in the abdomen;
  • Difficulty in breathing;
  • Spotting or bleeding, which may last for three months;
  • Pain in breasts;
  • Frequent urination;
  • Extreme fatigue; and
  • Pelvic pain.

Success Rate of IVF with Frozen Embryo 

The success of IVF frozen embryo transfer depends on several factors, such as the cause and duration of infertility, health condition and BMI of the mother, uterine receptivity, quality of the embryo (embryo grade), and most importantly, the mother's age. The higher the mother's age, the lower the IVF success rate with the frozen embryo. In general, the frozen embryo transfer success is 60% for women under the age of 35 and %20 for women above the age of 40. 

Mother age is one of the main factors affecting the success rate of frozen embryo transfer.

When is a Frozen Embryo Cycle Recommended?

A frozen embryo cycle is typically recommended when multiple healthy embryos are created during an IVF or ICSI cycle, but only one or two are transferred to the uterus immediately. The remaining embryos can be frozen and used in a future IVF cycle if the initial transfer does not result in a pregnancy or at a later time to create a sibling.

In some cases, a woman may be advised to freeze all her embryos and not transfer any immediately if the lining of the uterus has not developed properly or if she is at risk of developing ovarian hyper-stimulation syndrome (OHSS). It is also becoming more common for fertility specialists to recommend freezing all embryos because the more natural environment of a later cycle may increase the chances of establishing a pregnancy.

Freezing embryos can also be an option for women who wish to delay pregnancy until their late 30s or early 40s but understand that they may not have suitable eggs at that time.

Frozen Embryo Transfer Cost

The cost of IVF with frozen embryos depends on the procedure's price, embryo cryopreservation duration, hospital facilities, doctor's fees, medications, and the number of lab tests required. It would be best to ask your specialist or a fertility clinic for the exact cost of IVF with frozen embryos.

Chance of Twins with Frozen Embryo Transfer

During the IVF procedure, some specialists transfer two or more frozen embryos into the mother's womb to increase the chance of pregnancy. In some cases, more than one embryo attaches to the uterine wall and forms multiple pregnancies. The chance of twins with a frozen embryo is not very high, but if you do not intend to have twins in IVF or even triplets, discuss it with your doctor before frozen embryo transfer (FET). 

Signs of Successful IVF with Frozen Embryo 

  • No period after embryo transfer: Menstrual bleeding no longer occurs when the embryo attaches to the uterine wall.
  • Clear mucus discharge after embryo transfer: an increase in vaginal discharge can signify successful IVF with frozen embryos. Usually, women have clear mucus in the early weeks of pregnancy.
  • Sore breasts after frozen embryo transfer: Most women experience swelling, tenderness, and pain in their breasts at the beginning of their pregnancy. This happens due to hormonal changes in the body.
  • Feeling sleepy and tired after IVF: During the first stages of pregnancy, the amount of progesterone in the body increases, which results in extreme fatigue and muscle cramps. 
  • Headache and dizziness after FET (frozen embryo transfer): if the embryo transfer is successful, you may experience severe hypotension and hypoglycemia. As a result, you might feel down all day and experience headaches, dizziness, and even fainting.

Positive Signs After Embryo Transfer
Read more: How to Know if Embryo Transfer has Worked?

Signs of Successful IVF with Frozen Embryo


To summarize, frozen embryo transfer is the final step of the IVF process, through which the fertilized egg(s) is directly transferred into the mother's uterus using a catheter. IVF with frozen embryos is a complex procedure and should be done in a standard hospital and under the supervision of an experienced doctor. Luckily, in Iran, thousands of knowledgeable physicians and well-equipped fertility clinics offer the best healthcare services at a reasonable price.

IVF in Iran

If you intend to do IVF with frozen embryos in Iran, contact Raadina Co. to get more information about the top fertility clinics in the country and the price of this operation in Iran. Raadina Team offers you special embryo transfer packages, which include booking doctor's appointments, applying for a medical visa, arranging transportation in the country, and booking suitable and affordable accommodations.

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FAQs about Frozen Embryo Transfer

How many days after your period is the frozen embryo transfer done?

If a three-day embryo is being transferred, the FET takes place on the 18th day of your cycle, and if a five-day embryo is used in IVF, FET happens on the 20th day of your period.

Are frozen embryos better than fresh ones?

Recent studies show frozen embryos have a higher implantation chance and live birth rate than fresh embryos.

How long does a frozen embryo transfer cycle take?

Based on the general FET timeline, each cycle of IVF with a frozen embryo takes three to four weeks. In the first two weeks, the uterine lining is prepared for implantation, and the next two weeks are dedicated to preparing the womb for holding the baby and adjusting the hormones.

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  • پیش فرض

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