When you schedule an egg retrieval as part of your IVF process, what’s likely top of mind is whether you’ll make enough eggs to successfully conceive. What you might not know is that your doctor actually retrieves several different types of eggs during a retrieval. Understanding what those different types are gives you a better idea of what to expect from the process.

Mature Eggs

Each month, your ovaries naturally produce multiple follicles, which are fluid-filled sacs that each contain one egg. Ordinarily, only one of these eggs reaches maturity and is released around the 14th day of your menstrual cycle, and is the only egg capable of being fertilized.

However, when you have an egg retrieval, the goal is to retrieve as many mature eggs as possible at the same time. That way, there’s a better chance that one or more of the eggs retrieved can be successfully fertilized and result in a healthy pregnancy.

In order to stimulate your ovaries into producing more mature eggs than your body typically would, you’ll need to give yourself daily injections of fertility medication: one stimulates your ovaries into allowing more follicles to mature into eggs; the other keeps you from ovulating until it’s time to harvest the eggs.

Once there are enough mature eggs, you receive another injection that triggers your body to release the eggs. About three days later, your eggs are harvested through the egg retrieval process. The number of eggs retrieved will vary by person and can be affected by many factors, including your age and other conditions, such as polycystic ovary syndrome (PCOS). On average, about 80 percent of retrieved eggs are mature.

Immature Eggs

During your regular menstrual cycle, the majority of your eggs remain immature. Although each ovary produces multiple follicles each month, only a single egg is selected to mature. All the other eggs fail to develop, and your body breaks them down within your ovaries.

As you prepare for an egg retrieval, your proportion of mature versus immature eggs shifts. While the medication causes many more eggs to mature, not all eggs will be mature at the time of your egg retrieval.

On average, approximately one-fifth of eggs harvested during an egg retrieval are immature and incapable of being fertilized. It’s important to remember that having immature eggs is natural, and no reason to get discouraged.

Genetically Normal Eggs

Egg maturity isn’t the only factor that impacts IVF. The genetic health of your eggs also matters. And you may not realize that regardless of your age or known health problems, not all of your eggs will be genetically normal.

The number of genetically normal eggs from an egg retrieval varies widely, though your age greatly influences that number. For instance, if you are in your early 30s, the majority of your eggs (75-90 percent) are likely to be genetically normal. However, once you reach your 40s, that number drops to around 50 percent.

In many cases, genetically abnormal eggs will not become fertilized, so don’t be surprised if many of your mature eggs retrieved aren’t viable. The important thing to remember is that every mature, genetically normal egg retrieved gives you a chance at a successful pregnancy.

Genetically Abnormal Eggs

Genetically abnormal eggs are a reality for women of all ages. In fact, it’s quite common for eggs to have the wrong number of chromosomes, though as previously noted, your chances of releasing genetically abnormal eggs increases with age.

In some cases, genetically abnormal eggs won’t fertilize, in others they’ll become fertilized but won’t properly develop. These genetic abnormalities are often responsible for infertility and miscarriages.

As you are likely aware, genetic abnormalities can cause birth defects and disorders. Even if your eggs are successfully fertilized and the embryo successfully implants and grows, it’s still possible to have a child with a disability due to genetic abnormalities.

Genetic Testing

Many patients choose to have their embryos genetically tested before implantation to both screen for disorders and identify the sex of the embryo. Preimplantation genetic testing, or PGS (also known as PGT-A), also helps us select the healthiest embryo or embryos for transfer. PGS is often performed–and recommended–if you’re older than 37 because of the increased risk of genetic abnormalities. Talk to your doctor about whether genetic testing might be right for you.

Egg Retrieval – Realistic Expectations

It can be disheartening to hear that 20 eggs have been harvested, but only three were viable. Or you may find that you only had a small number of mature eggs and none or only one was viable. It’s  important to remember that these are common scenarios, and it can take multiple attempts to retrieve enough healthy eggs for a successful IVF and pregnancy.

We hope that you’ll now go into your egg retrieval with a better understanding of what to expect from the process. While all your eggs won’t go on to become healthy embryos, genetic testing and IVF provide much better odds for a successful pregnancy.

Interested in IVF? The first step is to schedule a consultation. Our team will do a thorough exam and run tests to determine the cause of your infertility, and discuss the necessary next steps, including egg retrieval

Everyone here at Halo Fertility wants you to be comfortable with your treatment. So if there is anything you don’t understand, we’re always happy to answer your questions!