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IVF
Egg retrieval is over. You're home on the couch, probably sore, possibly relieved, definitely anxious. And now you wait for the call — or the message — that tells you what happened.
The days after retrieval are some of the most emotionally intense in the IVF process, not because of what's happening to your body (though recovery matters too), but because of what's happening in the lab. Your eggs are being fertilized, your embryos are developing, and you have absolutely no control over any of it.
This guide walks through what happens in the lab day by day after retrieval, what the updates you receive actually mean, and what to expect physically as your body recovers.
Immediately after your eggs are retrieved, your embryologist assesses each one. The fluid aspirated from each follicle is examined under a microscope to identify and isolate the eggs. Not every follicle yields an egg — this is normal and expected.
Each egg is then assessed for maturity:
Your first update — the number of eggs retrieved and how many are mature — typically comes the same day or the following morning.
Fertilization happens on the same day as retrieval, using one of two methods:
Conventional IVF: Sperm are placed with each mature egg in a dish, and fertilization occurs naturally.
ICSI (intracytoplasmic sperm injection): A single sperm is injected directly into each mature egg. ICSI is used when sperm quality is a concern, when previous cycles showed poor fertilization, or as standard practice depending on your clinic's protocol.
Your doctor will have discussed which method is appropriate for your situation before retrieval.
This is usually the first substantial update you receive after retrieval — and for most patients, it's the one that sets the emotional tone for the rest of the week.
Your embryologist checks each egg for signs of normal fertilization. A normally fertilized egg shows two pronuclei (2PN) — one from the egg and one from the sperm. This confirms that fertilization has occurred correctly.
In general, fertilization rates vary depending on egg and sperm quality, the fertilization method used, and individual factors. It's expected for the numbers to decrease from eggs retrieved to eggs fertilized — this is a normal part of the process, not a failure.
Not every mature egg will fertilize. Eggs that show abnormal fertilization (0PN, 1PN, or 3PN) are not viable and will not be cultured further.
At Pollin, your fertilization report is delivered through the Pollin App — typically the morning after retrieval. You receive the numbers clearly, without having to wait for a phone call or wonder when someone will get back to you.
Your fertilized eggs are now embryos, and they're dividing.
By Day 2, a normally developing embryo has divided into approximately 2–4 cells. By Day 3, it should be at approximately 6–8 cells. Your embryology team monitors this development to ensure the embryos are progressing on schedule.
At most clinics, you may not receive a specific update on Days 2–3 unless something requires attention. Some clinics provide a brief Day 3 update; others wait until Day 5.
In a conventional lab, embryologists assess development by briefly removing embryos from the incubator at set intervals — Day 1, Day 3, Day 5. Each removal exposes the embryo to a change in environment.
In a lab using time-lapse incubation — like EmbryoScope+ — embryos are never removed. A camera inside the incubator captures an image every ten minutes, creating a continuous developmental record. Your embryology team can see not just where the embryo is at Day 3, but exactly how it got there — the timing of each cell division, whether divisions were symmetrical, and whether there were any abnormalities along the way.
This continuous record is more informative than a few point-in-time checks. It's also what allows AI-assisted assessment tools to evaluate embryos based on their full developmental history rather than a single snapshot.
Between Day 3 and Day 4, embryos undergo compaction — the individual cells begin to merge and form a tighter structure called a morula. This is a critical developmental transition. Not all embryos that looked healthy at Day 3 will compact successfully.
If your clinic provides a Day 3 or Day 4 update, you may hear about how many embryos are still developing on track. It's normal for some embryos to arrest (stop developing) during this phase. This is not a reflection of anything you did or didn't do — it's embryo biology.
Day 5 is the milestone most patients are focused on. Embryos that have continued developing should now be at the blastocyst stage — a more complex structure with two distinct cell types:
A blastocyst also has a fluid-filled cavity (blastocoel) that expands as the embryo develops.
On Day 5 (or Day 6, for embryos that develop slightly slower), your embryology team grades each blastocyst. Grading systems vary between clinics, but the most common uses three components:
A "4AA" embryo, for example, is a fully expanded blastocyst with a high-quality inner cell mass and trophectoderm. A "3BB" is a less expanded blastocyst with moderate-quality cell populations. Both can result in healthy pregnancies.
The number of blastocysts you have on Day 5 will be lower than your fertilization number on Day 1. This is expected. As a general reference in the broader population, conversion from fertilized eggs to usable blastocysts varies depending on many factors including age and egg quality. Your care team will discuss what your specific numbers mean in the context of your situation.
At Pollin, your Day 5 report — including embryo grades — is delivered through the Pollin App. If your embryos are assessed using CHLOE™ by Fairtility, the AI-powered decision support tool supplements your embryologist's grading with an additional layer of developmental data drawn from the time-lapse record. You receive a personalized embryo report as part of your cycle.
Blastocysts that are graded as viable are frozen using vitrification — an ultra-rapid freezing process that prevents ice crystal formation and preserves embryo quality. Vitrified embryos can be stored for years and have high survival rates when thawed.
If you've elected preimplantation genetic testing, a small biopsy of trophectoderm cells is taken from each blastocyst before freezing. These cells are sent to a genetics laboratory, and results typically return in one to two weeks.
PGT-A identifies embryos with the correct number of chromosomes (euploid) before transfer, which provides additional information to help your doctor select embryos for transfer. In the broader population, transferring chromosomally normal embryos has been associated with lower miscarriage rates — though individual outcomes vary. PGT-A is most commonly considered for patients over 35 or those with a history of pregnancy loss.
While the lab work unfolds, your body is recovering from the retrieval procedure. Here's what's normal:
If you show signs of any of the below directly after your egg retrieval it is always best to err on the side of caution and contact your care team.
At Pollin, you can message your care team directly through the Pollin App at any point during recovery. During clinic hours you'll hear back promptly. After hours, an on-call nurse monitors messages until 9pm, and overnight questions are answered first thing at 7am.
The days after retrieval are a specific kind of difficult. You're physically recovering while simultaneously receiving information — in stages — about the future of your cycle. Each update either brings relief or recalibration.
Attrition is expected. The numbers drop at every stage — from follicles to eggs, from eggs to mature eggs, from mature eggs to fertilized, from fertilized to blastocysts. This is normal biology, not a series of failures.
Your Day 5 number is not your outcome. Even a single high-quality blastocyst can result in a healthy pregnancy. The relationship between embryo count and final outcome is not as linear as it feels in the moment.
You are allowed to feel whatever you feel. Relief, grief, frustration, hope, numbness — all of it is legitimate. The post-retrieval period demands a lot emotionally, and there's no right way to experience it.
How many eggs is a good number after retrieval?
There is no universal "good" number. Egg count depends on your age, ovarian reserve, stimulation protocol, and individual response. Your care team will contextualize your number based on your specific situation.
When will I get my fertilization results after IVF egg retrieval?
At Pollin, your fertilization report is delivered through the Pollin App the morning after retrieval. At other clinics, you typically receive a phone call on Day 1.
What percentage of eggs make it to blastocyst?
Conversion rates from fertilized eggs to usable blastocysts vary based on many factors in the broader population, including age and egg quality. Your care team will explain what your specific conversion means for your situation.
Is it normal for embryos to stop developing after Day 3?
Yes. Not all fertilized eggs will develop to the blastocyst stage. Embryo arrest at various stages is a normal part of the process and does not indicate that anything went wrong with your care.
How long does it take to recover from egg retrieval?
Most patients return to normal activity within one to two days. Bloating and mild cramping may persist for up to a week. Strenuous activity should be avoided until your doctor clears you.
What is embryo grading and what do the letters mean?
Embryo grading assesses the blastocyst's expansion, inner cell mass quality (A, B, or C), and trophectoderm quality (A, B, or C). A "4AA" is a top-grade blastocyst, but embryos graded BB or even BC can result in healthy pregnancies. Grading is a selection tool, not a prediction.
Waiting for your embryo update? Your results are delivered through the Pollin App as soon as they're available. Questions? Message your care team directly. Book a consultation to get started — no waitlist, and we handle your referral.
Pollin Fertility was founded in 2023 with a mission to develop the most advanced clinical, digital and IVF, egg freezing and andrology lab technology to improve the fertility patient experience and treatment outcomes.
Pollin has 2 flagship, full-service clinics:
Pollin Toronto: located at 2360 Yonge St.
Pollin Ottawa: located at 303 Moodie Dr. in Bells Corner
To provide greater access to patients who need high-quality fertility care, Pollin has satellite monitoring clinics in Markham and Sudbury Ontario, with more on the way.
To learn more about the fertility treatments and services offered at Pollin visit www.pollinfertility.com
To book an OHIP-covered consultation with one of fertility specialists or click the link below.
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