What is Fresh Cycle?
In a fresh cycle the embryo transfer is performed following ovarian stimulation. The process involve the initial hormonal treatment to regulate the menstrual cycle, followed by ovarian stimulation to develop multiple eggs, egg retrieval procedure, invitro fertilization and transfer of the resulting embryo in the same cycle. Embryo transfer is usually performed one to five days after successful fertilization.
What are the Disadvantages of Fresh Cycle?
During ovarian stimulation levels of the hormones are elevated. This results in presence of high levels of fertility hormonal compared to the normal levels in your body at the time of the embryo transfer. This makes it more difficult for an embryo to implant.
The successful implantation of embryo requires a receptive uterine lining. It has been observed that high levels of fertility hormones at the time of embryo transfer may reduce the receptivity of the endometrium. Your womb may not have ideal state for embryo implantation which makes it difficult for an embryo to attach.
What is Frozen Embryo Transfer Cycle?
It is also known as FET cycle. In FET cycle the thawed embryos which were frozen in a previous IVF cycle are used and transferred in the uterus.
What are the Benefits of FET Cycle?
The FET cycle allows your body to recover from the ovarian stimulation performed in the IVF cycle and the endometrium may be more receptive to implantation of embryo. Your womb will be having a more ideal environment for implantation to occur.
FETs are considered less stressful than fresh cycles because they already have the viable embryos and they don’t have to worry about egg development, egg retrieval, fertilization and production of viable embryos. FETs requires only few ultra sonography scans, making it easier.
Further you can schedule the date of the embryo transfer and plan for it. The risk of ovarian hyperstimulation syndrome and high order multiple pregnancies can also be reduced.
How Embryo are Cryopreserved?
In recent years there are advances in methods of embryo cryopreservation. With the traditional slow freezing method of embryo freezing, many embryos might get damaged. Vitrification is an advanced method of embryo freezing. Vitrification of embryos cools cells very rapidly. The process avoids intracellular and extracellular ice formation. The vitrification does not alter the quality of cryopreserved embryos. However vitrification of embryos require skilled and experienced embryologists.