If you’ve gone through an IVF cycle and have extra healthy embryos, you can freeze them for future treatments, avoiding the need to go through the egg retrieval process again. Freezing embryos is also a great way to protect your fertility using sperm from your partner, co-parent, or a donor, as embryos generally survive the freezing and thawing process better than just eggs or sperm.
What is Embryo Freezing?
It’s a bit different from egg freezing, although they share similar initial steps in line with hormone-regulated or natural IVF. In embryo freezing, the eggs collected during an IVF cycle are fertilized with sperm and then cultured in the lab for about five to six days until they develop into embryos. Once matured, the healthy embryos are cooled and safely stored for future use. Typically, the whole freezing process takes around four to six weeks, but this can vary based on individual circumstances.
Getting Started: Consultation and Assessment (Up to 14 Days)
Before diving into treatment, you’ll need a consultation and fertility assessment. This includes reviewing your medical history and performing necessary tests and scans to tailor the best plan for you. Tests may involve checking hormone levels to see how well your ovaries and womb are functioning, as well as scans to evaluate your reproductive anatomy. If you plan on using sperm from someone you know, they’ll need a fertility assessment too. If using sperm from a bank, there will be extensive testing beforehand. Expect to visit the clinic a couple of times over about two weeks for these assessments and to discuss results with your consultant.
Ovarian Stimulation (About 14 Days)
Embryos are usually frozen in batches to maximize the chances that viable, high-quality embryos survive thawing later on. Ovarian stimulation boosts egg production, allowing multiple eggs to be collected, as normally only one egg is released per menstrual cycle. This phase can either start right away or involve a two-week suppression of your menstrual cycle. The actual stimulation period typically lasts around 14 days, depending on when your follicles are ready for the trigger injection.
Egg Retrieval (15-20 Minutes)
During stimulation, you’ll have several appointments for scans to monitor egg development. When the eggs are ready, you’ll take a trigger shot at home, and about 36 hours later, you’ll return to the clinic for egg retrieval, which takes about 15 to 20 minutes. You’ll need someone to accompany you home afterward.
Fertilization (One Day)
On the day of retrieval, your eggs are fertilized in the lab using sperm from your partner, co-parent, or donor. Depending on male fertility factors, we may use a technique called intracytoplasmic sperm injection (ICSI), where a single sperm is injected into each egg.
Embryo Culture (Five to Six Days)
The fertilized eggs, now embryos, are incubated for five to six days to allow them to develop into blastocysts, which have a higher chance of successful implantation. Some clinics use advanced technology like an Embryoscope™, which creates time-lapse videos to help identify the strongest embryos.
Embryo Freezing (Instant)
Once matured, the blastocysts are examined and graded based on their characteristics. We typically freeze only the highest-grade embryos, as they have the best chances for future implantation. The freezing process, known as vitrification, involves rapidly freezing the embryos in liquid nitrogen, which takes just minutes.
Storage (Up to 55 Years)
Your embryos are securely stored in liquid nitrogen tanks using labeled straws containing your unique information. In the UK, you can store embryos for up to 55 years, but you’ll need to renew your consent every ten years.
How Many Times Can Embryos Be Frozen?
Ideally, we freeze embryos just once to minimize risks of damage from thawing and refreezing. At our clinics, we typically thaw one embryo at a time to preserve the rest without wasting any.
Success Rates
Recent data suggest that frozen embryo transfers have success rates comparable to fresh transfers. Notably, our clinics consistently outperform the national average regarding success rates for frozen transfers.
If you’re looking into fertility preservation or considering IVF with frozen embryos, we’re here to assist. Check out some other helpful resources like this one on pregnancy and the costs of pregnancy insurance. Also, if you’re interested in at-home options, Make a Mom provides excellent kits for artificial insemination.
In summary, the embryo freezing process involves several steps from assessment to storage, taking roughly four to six weeks. It can be a beneficial option for those looking to preserve fertility for future use.