How long does a frozen embryo transfer take?

In most cases, frozen embryo transfer takes 1 month, so it’s like a normal cycle. If the patient undergoes hormone replacement therapy to prepare the endometrium, they start it on day 1 of the period. If the patient wants to start a natural cycle, they contact us on the first day of the period, then we schedule the first scan. After that, we go through different phases, so the transfer takes place around day 15-20 of the cycle, and 12 days later, they do a pregnancy test.

In some cases, and that’s something that should be decided based on individual cases, it may be necessary to do the down-regulation before the patient starts the treatment. It is because of problems like adenomyosis or things like that. In these cases, the treatment starts the previous cycle, on day 20-21, the patient gets an injection to down-regulate the ovaries, and then once they have their period, they start the hormone replacement therapy that is going to be mandatory in this kind of treatments. That’s the only case in which the treatment may last more than one cycle. The remaining cases, regardless of what type of preparation you eventually want to do, are going to last for one cycle.

For the actual procedure itself, the embryologist will be in touch with you. For example, if you have a transfer on day 3 or 5, they will let you know in the morning that your transfer is scheduled for that day. Usually, it is scheduled for the afternoon so that you can have ample time to get ready and come to the clinic. The procedure itself is very very simple. It’s like a smear test using a speculum and it can take from 15 to 20 minutes, depending on the technique used. So when you come to the clinic, you will be told to come with a full bladder or half full bladder because it is usually done now under ultrasound guidance.

Sometimes, the actual delay in the embryo transfer is to check the position of the uterus exactly by the ultrasound scan to see if your bladder is already full enough. Mind you, you also have to consider whether your uterus is anteverted or retroverted and hence, the doctor will be guiding you as to how much you should fill the bladder. Sometimes, when we feel that you are overfull, we can ask you to empty a little bit of your bladder so that you are comfortable.

There are other clinics that use a transvaginal scan, which I believe is a very good technique – but not every clinic has this facility. This technique does not need a full bladder at all. A frozen embryo transfer does not need any anesthetic, it is not like the egg collection. It is a straightforward procedure with a very tiny plastic catheter that we insert. By the time we say we are ready, we put the speculum, we inspect the cervix, we clean the cervix and then we ask the embryologist to prepare the embryos. All of this is taking roughly 10 to 15 minutes, and after that, you’ll be asked to stay relaxed on the couch for another 15 to 20 minutes. And then you can go home.

Frozen embryo transfer (FET) and the duration of frozen embryo transfer including the preparation of the endometrium depends on whether it is a natural cycle or a medicated cycle. In a medicated cycle, which is more often used, we prefer to give about 12-18 days of estrogen, ideally, before we start the progesterone. It also depends on whether we have day 3 embryos or day 5 embryos frozen. If we have day 3 embryos frozen, we give 3 days of progesterone; if we have day 5 embryos frozen, we give 5 days of progesterone.

In total, from the beginning of the cycle, the whole preparation may last between 16-20 days before the time of the embryo transfer. The embryo transfer itself is a procedure that takes about 5-10 minutes if we do not have any problems passing the catheter. It is a very straightforward procedure.

The same thing happens in a natural cycle, as well. We observe a follicle that usually gets big enough to ovulate in about 12-16 days, depending on how many days of the cycle the woman has. Then, again, the embryo transfer can happen 5 days later if we are talking about blastocysts.

Sometimes, we prefer to downregulate the ovaries first before we start stimulating them. At our unit, this usually happens with an injection which is called GnRH analogue, and is given 21 days after the previous period. Usually, it is performed this way: 21 days after the last period we give the injection, 14 days later the patient has an initial ultrasound scan, she takes estrogen for about 14 days, has a repeat scan, and 5 days later, has the embryo transfer.

Usually, we do embryo transfer between day 17 and 21 of your cycle. The reparation before embryo transfer takes 10-12 days till the first ultrasound and then we plan the embryo transfer. The procedure for embryo transfer is very quick. It takes one minute. But altogether at the clinic, it takes one hour with all the formalities that are necessary to sign like informed consent, and other check-ups, etc. It is necessary to stay in the operating room for some time, for a minimum of 20 minutes. So altogether, it takes one hour for the procedure, and 17 days of preparation minimum.

Most of the time we call the patients in the afternoon or in the noontime because during the morning we thaw the embryo, prepare them, and then we call the patient. We check if they are suitable for the transfer because sometimes after thawing, if the embryo has a genetic abnormality or if they were not frozen properly, they will degenerate after the thawing. So, in this case, we have to open maybe another embryo to thaw. So in this case, on the day of the transfer, we call the patient at noon or in the afternoon. During the morning, in 45 minutes to two hours, we can thaw the embryo and we can see if they are suitable for the transfer or not, and we wait a little bit for the swelling, etc.

Then, we tell the patients “yes, we have thawed your embryos, they are suitable for the transfer and we will realize your transfer”. Before the transfer, we always have to share the information about the embryos with the patients, and we are informing the patients and then we are taking them to the operation room. In the operation room, we proceed this way: we check first the patient’s bladder, if the bladder is full in this case, the embryo can be passed very easily during the transfer so this is very important. It means that we check the bladder, if the bladder is okay, we would be asking the embryologist, if the embryologist also says ‘okay you can take the patient’, in this case, we take the patients to the operation room and carry out the embryo transfer. The embryo transfer process itself is 5-10 minutes, very easy, and not painful.

The frozen embryo transfer can be done in two different ways. The preparation can be done in two different ways. One is the medicated cycle, where the patient is exposed to at least two weeks of hormonal replacement therapy, also known as HRT. This involves the use of tablets or patches to try and build the lining of the womb. That will then be followed by the progesterone in the form of either pessaries or vaginal tablets or injections for as long as it is needed. In that sense, with a medicated cycle, the preparation is probably between 2-3 weeks. The other option is to have the embryo replaced on a natural cycle, and the natural cycle involves monitoring the ovulation that might occur in that cycle. that is very much dependent on the patient. On average, a woman would ovulate between day 12 and day 14 over the menstrual cycle, but some women ovulate a little bit earlier, and some women ovulate a little bit later. It is important that the ovulation occurs because that is a sign that the lining is ready then for implantation.

“Medicated” cycles take a little longer as you will need to take medications that will temporarily “switch off” your ovaries in the month leading up to the cycle month.  Once you begin your next period, you will have approximately 10-12 days of medicine (estrogen) to thicken your lining followed by 3-5 days of medicine (progesterone) that will prepare the lining to receive the embryo.
Natural cycles begin on the first day of your period and once ovulation is detected approximately 14 days later, the embryo thaw and transfer is scheduled within 3-5 days according to the developmental stage of your frozen embryos.

Normally, on average, it will take like 3 weeks more or less, it can be a little bit less or it can be a little bit more. This includes all the preparation of the patient, of course, we have different kinds of preparations so it would depend on which kind of preparation that we would do, but normally we have two kinds of cycles. We have the medicated cycle – in which we use hormones to maintain the endometrium lining growth and when we see that everything is correct, we will program the transfer which is normally 3 weeks. The first one is always done more or less on day 10 approximately of preparation with hormones.

And on the other hand, is the natural cycle – in which we will need to do more controls probably because we will need to follow accurately and a little bit better how the follicle grows and the endometrium lining grows because we need to know when the patient is going to ovulate because the embryo transfer needs to be absolutely synchronized with the ovulation. On average, this is going to take, as I said, 3 weeks and it could be more than that.

Regarding the embryo transfer itself, the transfer lasts for 15 minutes, it is a simple process that is done without any anesthesia, and normally we recommend our patients to come over the night before the embryo transfer because on the same day of the transfer we need to see how the embryos survive the thawing and we want to make sure that they are correct before putting them back. That is why we will prefer our patients to be here the night before, we need to be sure that they are here before we thaw the embryos.

Then, we normally recommend going back to your country the day after not because it is absolutely demonstrated that it can have an impact traveling the same day of the transfer but we think that it is less stressful for the patient and it is something that if it’s possible it is something that we normally counsel.