Frozen Embryo Replacement Cycle

Natural cycle

In a natural cycle we need to determine the appropriate day for replacing frozen-thawed embryos by making sure ovulation has occurred. Ovulation is responsible for making the lining of your uterus receptive to the embryos. Your IVF coordinator will guide you through the processes used to determine when the appropriate day is for embryo transfer.

Hormone replacement cycle

In a hormone replacement cycle we mimic the hormonal changes occurring during a natural cycle. Through the use of oestrogen (Progynova) tablets and progesterone pessaries, it is possible to create an artificial environment suitable for an embryo. No blood tests are required in a hormone replacement cycle. Oestrogen tablets (Progynova) are taken from day 5 of your cycle and you will have an ultrasound on day 14 of your cycle. This ultrasound will  confirm that the lining of the uterus (ie. the endometrium) has developed sufficiently for an embryo transfer to take place. If the lining is not sufficiently developed, the dosage of Progynova will be increased and another ultrasound performed.

Policy on transfer, freezing and storing embryos

The maximum number of embryos that we will transfer in the first embryo transfer cycle for women under the age of 36 is one. This is in accordance with the guidelines of the Reproductive Technology Accreditation Committee.  For frozen embryo replacement cycles we will discuss with you whether 2 embryos would be appropriate.

The advantages of embryo freezing are:

i) It allows an increase in the pregnancy rate while minimising the number of times the ovaries undergo stimulation
ii) It minimizes the number of times a female patients has to undergo an egg pick up procedure
iii) It may lessen the cost of achieving a pregnancy

The disadvantages of embryo freezing are:

i) If you become pregnant and still have embryos in storage, you will then need to decide what to do with the embryos at a later date
ii) Legal problems may occur when embryos are in storage and death or divorce occurs. This is covered in our consent form for your guidance and you will need to predetermine the fate of your frozen embryos when you sign your consent.