Answer from: Raúl Olivares, MD
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.
Answer from: Harry Karpouzis, MD, MRCOG, DIUE
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.
Answer from: Anna Voskuilen, MD
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.