The defence of the ovaries
Many oncology treatments may affect women’s fertility and ability to have children in the future. Thankfully, there are many options available to preserve the eggs in the ovaries before you start your oncology treatment. Dr Lizle Oosthuizen explains further.
There are many strategies to limit the damage on the ovaries, such as surgically lifting them out of the area of radiation or using shields. Your doctor may recommend taking, a GnRH agonist, to ‘shut down’ the ovaries during treatment and try to protect them. Unfortunately, this hasn’t been shown to improve future fertility and shouldn’t be relied on alone.
Women and girls who’ve gone through puberty can do a cycle of egg freezing in around 10 days. An assessment of the ovaries (egg reserve) is done, as well as how many eggs can be expected to be retrieved in one cycle. If time permits, we’re able to increase this number by doing two cycles. Your fertility specialist will do an ultrasound and request blood tests to best decide on how to stimulate your ovaries safely.
Depending on your diagnosis, more tests may be done to ensure low blood counts and increased clotting risks are accounted for when planning your treatment safely. Freezing eggs doesn’t guarantee a future pregnancy, as the embryos created are affected by the quality of the eggs, which is in turn affected by your age. This is why each patient will need an individualised assessment.
Small injections are administered into the fatty tissue over the tummy every day for around 10 days. These are easy to do, and you can do them yourself at home. At the same time, we can prevent you from ovulating by giving progesterone tablets.
Ultrasounds are done to monitor the growth of follicles after a few days of injections. A follicle is a sack of fluid containing the egg and it can be visualised on ultrasound, but not the egg inside. We assume every follicle has an egg, but some follicles may not contain eggs. Your doctor will keep monitoring the growth of the follicles every two to three days until multiple follicles have grown to an appropriate size which will indicate they’re ready to be triggered and retrieved.
The trigger refers to a final injection that makes the follicles think they’re starting the process of ovulation for them to mature enough to be fertilised. The egg retrieval is usually done under sedation in a theatre in a clinic. A needle is inserted into each of the follicles under ultrasound guidance, and each follicle is emptied of the fluid. This fluid is processed for eggs by the lab, and the mature eggs are then frozen for future use. This is a 10-15 minute procedure and you’re able to go home comfortably two hours later. You should only experience mild cramping and bloating which resolves in two to three days.
Storage of frozen eggs
Your eggs can be stored until you decide to use them. Should you require them, there is no known ‘upper limit’ of storage time. Should you decide to use them later, they’ll be thawed out and fertilised with your partner’s sperm. The embryos will be cultured in an incubator and then transferred to the uterus in a simple, painless procedure, much like a Pap smear. Excess embryos can be stored for future use should the first transfer not be successful, or if you would like to return for more pregnancies.
You may also choose to fertilise the eggs immediately with your partner’s sperm and create embryos. The benefit of egg freezing is that those eggs will always belong to you, and you can choose to use them as you see fit. Embryos will combine your partner’s DNA with yours, and this may complicate things in the event that your relationship ends, and you return to use the embryos.
We always encourage patients to make use of a disposition agreement to also say what you would like to be done with the eggs/embryos should anything happen to you.
Freezing eggs does have the limitation of not knowing the quality of the eggs and unfortunately the only test of this is when the egg is exposed to sperm and has to fertilise and develop. Not every egg will fertilise or develop into an embryo we can freeze, so creating embryos often gives you more information about the quality of the eggs. The technology used to freeze eggs is now so good that we don’t recommend one over the other in terms of survival of the egg or embryo. Your doctor can help you decide what is right for you.
Ovarian tissue cryopreservation
If a young girl hasn’t yet passed through puberty, this provides an excellent option. A small ‘key-hole’ laparoscopic surgery is performed, and a few pieces of one or both ovaries are removed. This tissue contains eggs that haven’t yet started to develop, and this tissue is then frozen. This procedure doesn’t cause menopause. If it’s required one day, the tissue is thawed by the lab and is transplanted onto the ovary or a structure nearby. This is no longer considered experimental and is offered in experienced clinics in SA. There are multiple live births reported from this procedure and it doesn’t have a long recovery time. Older women can also choose this option, although usually we offer egg freezing as it’s less invasive. The only time we don’t recommend this if the ovaries are involved or at high-risk of being infiltrated by cancer cells.
Effects on cancer diagnosis
None of the treatments described affect your chance of a recurrence or are associated with developing cancer later. Many studies have looked at women who did freeze eggs and compared their five-year survival to women who didn’t, and there was no difference in the rate of recurrence.
MEET THE EXPERT – Dr Lizle Oosthuizen
Dr Lizle Oosthuizen is a reproductive medicine specialist. She was part of the fellowship programme in reproductive medicine at UCT. She obtained her certification through the College of Medicine SA, as well as a masters in philosophy from UCT.
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