Frozen Embryo Transfer

Often after a cycle of IVF or GIFT there are embryos of a suitable quality that can be frozen and stored for future use. There are several advantages to this.  

Firstly if an IVF cycle is successful it can be, on average, two years before you will be ready to try for another baby and there is a risk that your ovarian reserve or egg/sperm quality may have changed sufficiently that IVF with fresh eggs is no longer a suitable treatment option.

Secondly, IVF is a stressful process and a frozen thawed cycle has the advantage of less medication (depending on the cycle option) and no egg collection or laparoscopic procedure.

New vitrification freezing techniques are improving the success rates of frozen transfers. Vitrification involves the quick freeze technique which reduces ice-crystal formation inside the delicate embryos thereby increasing the possibility of a successful thaw.

A frozen thawed embryo transfer mimics the body's natural processes to a degree, depending on the type of cycle undertaken.

A natural cycle frozen thawed transfer involves monitoring the period and transferring the embryo at the optimal time after ovulation has been observed to mimic nature as closely as possible. Progesterone to support the lining is administered after the transfer.

At the beginning of the period it is important for both partners to attend the CRGH to read and sign the consent to thaw the embryos and both parties must be sighted on the unit. Once both of these requirements have been met the embryos will be able to be thawed.

A single dose of antibiotics is taken prior to day seven (7) of the period. As with follicular tracking an initial scan appointment is made for day 10, 11 or 12 of the period (Mon-Fri only). At this point the doctor will advise when the next scan should occur and you will be advised to commence testing your urine for an LH surge.

Once ovulation has been confirmed by observation of a collapsed corpus luteum the transfer date will be decided. The date of transfer depends on the stage the embryo was frozen.

A medicated cycle is similar to IVF in that it is a two cycle process, however we do not stimulate the ovaries but promote the growth of the womb lining.

The first cycle is the period of down-regulation to suppress the body's hormone production. This is to prevent the spontaneous shedding of the womb lining during the second cycle.

The second period involves an internal scan days 1, 2, 3 or 4 of the period (Mon-Fri). This is to confirm that there are no barriers to treatment, for example a cyst. A consultation with a nurse will follow.

At this consultation instructions will be given regarding the single dose of antibiotics, the administration of the oestrogen medication (topical, oral, vaginal or a combination) and the booking of the next scan to observe the lining growth.

During this second cycle and prior to the thawing of the embryos both parties must read and sign the consent form and the male partner must be sighted on the unit.

Once the lining has reached an appropriate thickness, progesterone is administered either through injections or pessaries and starting a specific number of days prior to transfer. This time-frame is dictated by the stage the embryo was frozen at.