by Dr Agilan Arjunan, Fertility Specialist, KL Fertility Centre (Malaysia)
Just a few days ago an article about frozen embryo transfer was published in The Star .
In summary, the article mentioned about the advantage of deferring embryo transfer to a later date (ie freezing the embryo first and do the embryo transfer later). It says that by doing so, the miscarriage rate was lower and this leads to a higher live birth rate.
I completely agree with the findings and it concur with my own clinical experience.
Currently, IVF / ICSI can be broken into 2 segments :
a) Stage 1: Ovarian stimulation, egg collectian and fertilisation
b) Stage 2: Embryo transfer
Traditionally, Stage 1 & 2 are done in the same period cycle (fresh embryo transfer). We can get reasonably good pregnancy rate with fresh embryo transfer.
We used to freeze embryos when we are unable to transfer embryos in the same cycle (such as when the woman is at risk or developed ovarian hyperstimulation). Embryo freezing are not done electively.
Over the last few years, more research data supports elective embryo freezing. Furthermore, this method become more popular after introduction of a better embryo freezing technique.
But why frozen embryo transfer is better ?
To understand this , you must first understand what happens naturally in a woman’s period cycle. Every month, a number of eggs / oocytes are ‘prepared’ to grow but eventually only one egg will grow (and growing egg produces hormones to prepare the womb) and ovulate. After ovulation, the womb (uterus) makes the necessary changes and become ready to accept the embryo.
In an IVF, medications are given to grow many eggs. This process eventually produces high level of hormones which are not natural for the womb. Thus, eventhough fresh embryo transfer gives a reasonably good pregnancy rate, we can potentially achieve a higher pregnancy rate with frozen embryo transfer.
In a frozen embryo transfer, the woman ovulates herself, which means her hormones levels are in check and her womb gets ready naturally. The embryo/s is/are transfered after ovulation (typically Day 3 or 5 after ovulation).
Well, I guees it is time for us to break IVF / ICSI into 2 stages and do the necessary to optimise each stage of an IVF to get the maximum outcome out of one IVF cycle. This achieves a higher success rate.