The Philosophy of Freezing
IVF (in vitro fertilisation) is an amazing endeavour of modern science.
In a natural cycle, several follicles line up in the human ovary. These follicles are contenders in a competition mediated by hormones in which the body naturally chooses one winner. One ovarian follicle to become dominant. Within it, we hope for one egg to ovulate and to perhaps, make a baby.
The hormonal levels made by one follicle perfectly direct the formation of an ordered endometrium, a refreshed uterine lining. The lining of your womb is a base and a bed to welcome, invite and support a competent embryo. The endometrium is a living tissue, a complex cellular matrix, a communicating interface between mother and child. The embryo must call out and the endometrium must answer, accept and embrace the developing ball of cells so that it might form the beginnings of new life, placenta and child.
IVF (in vitro fertilisation) is an amazing endeavour of modern science. We have learned to stimulate the ovary so that instead of calling on one follicle and one egg in a natural menstrual cycle, many follicles are summoned (with hormonal medication) and many eggs are given the chance to ripen in the same cycle.
We understand that not every egg will be of equal potential. Our hope is that with increased egg numbers will come an increased chance of creating an embryo of high potential, with the energy, DNA integrity and touch of magic required to create a baby, often against the odds for infertile women and couples.
A historical approach to IVF has been to replace an embryo to the uterus in the same month it was created. However in doing so we realise we are making a big compromise. We know the high hormone levels that help multiple eggs to ripen cause the uterine lining (endometrium) to grow in a disrupted, disorderly fashion, to mature too rapidly, to close the window for successful implantation too early.
When we replace a high quality embryo in a stimulated IVF cycle, we guarantee that it is not being given the best chance of finding a receptive, nurturing endometrium to welcome it and secure its’ destiny.
Enter vitrification
We have over the last decade, improved the art of freezing embryos a lot. In modern practice, over 95% of embryos frozen via vitrification survive well. This allows us to give our patients the benefit of transferring their best embryo in a separate dedicated month, where IVF stimulation hormones have not been present, ensuring optimum conditions for maximising success in IVF.
Benefits of a dedicated freeze and thaw approach to IVF include the avoidance of OHSS (Ovarian Hyperstimulation Syndrome). A freeze first strategy also provides women and couples with the opportunity to know how many embryos have definitely resulted and been frozen from a single stimulated treatment before committing to the next step of embryo transfer.
Before moving on to embryo transfer, a good strategy for long term family planning in IVF can be to ensure an adequate number of healthy embryos are frozen and banked.
A freeze-first approach strategically can reduce the number of stimulated IVF cycles needed over time. This is because when a woman first attempts IVF, her prognosis is the best it will ever be from that point forward. She is biologically the youngest she will ever be and she has the highest ovarian reserve (egg count) she will ever have. Compared to a few years in her future, her personal IVF prognosis is considerably better. A freeze all strategy allows her to set herself up for present and future success, planning current and future pregnancies, reducing the risk that she will need to return to stimulated IVF treatment later in life in her efforts to grow her family.
Wave theory: a paradigm shift in IVF
Traditional IVF models have tried to do it all: stimulate the ovary and try to achieve a pregnancy in a single month. In this approach we compromise every aim.
Your doctor often cannot stimulate your ovary to achieve your best potential, due to concerns regarding hyperstimulation syndrome (a condition caused by dangerous hormonal side effects in IVF where a large number of ovarian follicles containing eggs are recruited).
We have safe medication strategies, to almost completely negate the risk of OHSS, however these can only be used in a freeze first cycle. By committing to freezing eggs and embryos as your goal from the outset of treatment, your doctor can both protect you from OHSS, and also achieve your best outcome in terms of the number of eggs you are capable of producing in a cycle.
Fact: there is another way
The ovary has follicles at every stage of maturity all the time. Physiologically we can call on the ovary at any time to catch a wave of maturing follicles and within them to recover potentially fertile eggs
These eggs can be used in IVF to create embryos at any day or stage of a woman’s menstrual cycle. Embracing ovarian wave theory and rethinking traditional IVF concepts opens the door to creating a more patient focussed woman friendly way of performing IVF with a goal of achieving excellence at every treatment stage.
Optimising preconception preparation.
Optimising egg yield in a stimulated cycle.
Holistically optimising the environment of implantation when an embryo is restored to the womb.
Striving for excellence over compromise at every stage of the IVF and implantation stages will improve cumulative live births for women and couples in IVF.
Separating the concept of embryo transfer from egg collection in an IVF and egg freezing context is incredibly liberating.
The ovary can be called upon to develop multiple mature eggs at any stage of a menstrual cycle. The way IVF has traditionally been performed puts women at the mercy of their menstrual cycle. Drugs start soon after the onset of a menstrual period, so that egg collection falls approximately in sync with the timing of when a natural ovulation might have occurred in the cycle.
Imagine divorcing this concept. Imagine a world in which you could plan your IVF start date. You could choose a date that suits your schedule. You could take a break to focus on your physical and psychological recovery and well being. You could break up your treatment into phases that are easier to cope with, with reduced discomfort and enhanced resilience.
In traditional IVF a woman rides a rollercoaster of hormones and emotions for a marathon across the whole month, preparing for egg collection, awaiting embryo outcomes, supporting a deficient luteal phase with a truckload of artificial progesterone that leaves you bloated, emotionally vulnerable and highly strung, only to put your precious embryo back into a less than perfect lining, directly hurtling into a “two week wait” to see if pregnancy has occurred.
Disrupting the disruption: Patient focussed IVF care
So what if IVF worked around your life instead of you working your life around IVF?
You plan your start date
You have a very good idea of when you will need time off work
Appointments are scheduled with plentiful advanced notice
Fewer medications are needed
Risks of ovarian hyperstimulation are mitigated and minimised
Treatment is broken up into achievable elements
You are given the opportunity to bank embryos to support your long term family planning goals.
Your body is nurtured to recover and revitalise to optimally prepare for your best chance of pregnancy in a future planned embryo transfer
The ovary, the pelvis and the endometrium: compromise and confusion
Following an egg collection, hormones are running wild and regardless of a surgeons skill, a haemoperitoneum forms (blood in the pelvis following oocyte retrieval) causing a significant degree of pelvic inflammation. The endometrium matures too rapidly under the influence of high hormone levels, a side effect of medications used during your treatment. There is often a premature progesterone rise in the context of ovarian stimulation, followed by a progesterone level crash and deficient luteal phase. In short, the environment is not ideally optimised for an embryo’s best chance of successful implantation.
IVF rescripted: Science and nature; the best of both worlds
By segregating the aspects of IVF into two different time frames, we can honour and optimise all elements of care:
Ovarian stimulation and embryo freezing,
Support recovery, honour natural endometrial receptivity and proceed to embryo transfer
This approach allows a woman to benefit from the best lessons that both science and nature have to offer. More importantly, this integrative approach leads to world’s best IVF pregnancy rates.
The definition of success: aiming for excellence at every step in IVF
Focussing on excellence at every time point in the IVF journey has been my perennial goal as an IVF expert. I have recognised the conflict between stimulation and implantation.
The solution to achieve the best of both worlds is to separate the processes in time, honouring each step, in it’s own right, outside of the traditional IVF cycle paradigm.
I also want to honour my patients experience during their care, recognising and addressing the pain points of IVF to help improve women’s quality of life throughout IVF treatment as a parallel goal to achieving best outcomes in terms of pregnancy success rates.
Written by Dr Raelia Lew
RANZCOG Board Certified CREI Fertility specialist, Gynaecologist and the Director of Women’s Health Melbourne.
Co-host of the Knocked Up Podcast, Co-founder of Ellechemy intimate wellness solutions. Raelia has a PhD in Preconception Health Promotion and Genetic Screening. Raelia is a leading Australian expert in IVF and egg freezing, pioneering a bespoke model of care.