Hello - Dr DiMattina here to discuss the differences of using a patient's natural menstrual cycle for a frozen embryo transfer as compared with a medicated cycle. I will also discuss how a 41 year old patient of mine benefited by using a single frozen embryo when her fresh embryo transfers failed.
Now, more than ever, patients are having their embryos cryopreserved and stored for later embryo transfer. There are many reasons for this increased use of embryo cryopreservation such as the common use of Lupron to trigger patients undergoing stimulated IVF to prevent ovarian hyperstimulation syndrome, more single embryo transfers to avoid multiple pregnancy, more common usage of PGD to search for genetic abnormalities and prevention of embryo implantation failure that may occur in stimulated IVF cycles because of the well known adverse effects of gonadotropins on the endometrium.
But is it better to perform a frozen thaw embryo transfer in a woman's natural cycle or a medicated cycle?
In a "medicated" frozen embryo transfer cycle, the patient takes estrogen for about 4 weeks and progesterone for about 2 weeks. The estrogen can be taken orally, injected or by patches applied to the skin. Progesterone is given either vaginally or by injection or both. Often Lupron or oral contraceptive pills are used in the beginning of the medicated cycle. The entire cycle takes about 4-6 weeks.
There are 2 circumstances that necessitate a medicated frozen embryo transfer. Any patient with irregular or absent menstrual cycles is best served with a medicated cycle for transfer. This ensures an orderly maturation of the endometrium which is critical for optimal embryo implantation. The second reason for performing a medicated cycle would be patient or physician convenience and scheduling. Patients of mine who travel a lot or who come from out of town can "program" their embryo transfer if they so desire.
Natural Cycle frozen embryo transfer (NCFET) is performed in patients whose menstrual cycles are regular to some degree, say every 25-40 days. It is far simpler than a medicated frozen embryo cycle as patients take estrogen and progesterone for only about 2 weeks after they are monitored and ovulated using a single injection of hCG. Thus, medicated cycles require the patient to take hormones and medications for 4-6 weeks and may cost more than NCFET. However, the embryo transfer in a natural cycle cannot be programmed, so the patient must be flexible and available when the time is right for her embryo transfer.
The good news is that multiple studies have shown (and my own experience confirms) that the pregnancy rates with the 2 types of embryo transfer methods are identical. There is simply no advantage of one type of embryo transfer compared with the other in terms of implantation or pregnancy outcomes.
At Dominion Fertility, most of our patients choose NCFET over a medicated transfer because of its simplicity. Again, those patients with highly irregular cycles are best served using a medicated transfer cycle.
Recently, by way of example, a 41 year old patient of mine achieved a successful pregnancy using her single frozen thawed embryo and NCFET. In 2012, she underwent 2 fresh stimulated IVF treatments at another local clinic. Two fresh embryos were transferred in her first cycle and 3 in her second but without success. One extra embryo was cryopreserved. Her menstrual cycles occurred every 28-30 days, so I recommended that we first perform a NCFET and it worked. After confirming her pregnancy with ultrasonography, she was referred to her Obstetrician.
Her failure of implantation using her fresh embryos may have been due to adverse effects of gonadotropins on her endometrium. Such effects are circumvented using NCIVF and many IVF centers are increasing their usage of frozen embryos for transfer.
I hope that this explanation has been helpful! Dr D