Infertility treatments: What is a healthy egg?

A quick primer on what fertility specialists look for in a woman’s eggs.

egg quality graphic three smiling eggs Illustration: Nica Patricio

What are doctors looking for? Doctors can’t really tell if an egg is high or low quality simply by looking at it. There may be abnormalities, such as discolouration or open spaces in the eggs, but these irregularities may not affect the egg’s ability to be fertilized, says Robert Casper, a fertility specialist at Trio Fertility in Toronto.

All mature eggs are fertilized and the embryos are cultured for five days (until they reach the blastocyst stage). If the embryo makes it to the blastocyst stage, there is an estimated 50/50 chance that it will have normal chromosomes and result in a baby. “What we’re really looking at is how the egg fertilizes and develops into an embryo,” says Casper. “If the embryo implants, it doesn’t really matter what the egg looks like; it means the egg was normal and the quality was okay.”

“The primary determinant of egg quality over the course of a woman’s reproductive life is her chronological age,” says Ari Baratz, a fertility specialist at the Create Fertility Centre in Toronto. As women age, the quality of their eggs diminishes, and so do the chances of getting pregnant without assistance, he says. Typically, the peak of good-quality eggs is around the age of 25, with quality declining after the age of 35.

What matters more: quality or quantity? Both quality and quantity matter. It’s possible that a woman could have difficulty conceiving if she has a large quantity of poor-quality eggs or a limited number of high-quality eggs. But having a good supply of eggs can be helpful, says Baratz, because having a large quantity usually implies that some eggs will be viable in women under 35. In any given egg population, not all the eggs will be healthy, so it’s good to have a decent number to work with. (Women over 40 may experience egg-quality issues, even if tests show that they have lots of eggs.)

What is ovarian reserve, and how do you test for it? Ovarian reserve is the technical term for the number of eggs a woman has. A woman’s ovarian reserve is assessed via ultrasound and various hormone tests. One of these hormones tests is for Anti-Mullerian Hormone (AMH), a hormone that helps indicate if a woman has a lot of eggs or not. The higher the amount of AMH found in a woman, the more eggs she has. “If the AMH is quite low, that doesn’t necessarily mean that the remaining eggs are poor quality,” says Casper. “It doesn’t predict pregnancy. But it does mean that people may run out of eggs early or may not respond well to fertility medications.”

Can you still get pregnant if you have poor egg quality? As Casper says, it isn’t an all-or-nothing situation. “Usually the percentage of normal eggs decreases over time, but it doesn’t go to zero necessarily until people probably get into the age range of 44 or 45,” he explains.


While there really is no single treatment to improve egg quality, you still have options. “One could move to donor eggs, or eggs from another female, as another treatment for very poor egg quality,” says Baratz, “but that would be after multiple times of treating a woman with her own eggs if all else failed.”

What can affect the quality of an egg? Smoking, drugs, prolonged exposure to environmental contaminants or pollutants and intense radiation or chemotherapy can lead to a decrease in healthy and normal eggs, as well as a reduction in the number of eggs.

Are there ways to improve the quality of an egg? Some studies have shown that coenzyme Q10 and vitamin D can help improve the quality of eggs. Coenzyme Q10 increases energy production by mitochondria (the battery of the egg), which increases the likelihood of a good chromosomal makeup for the eggs and boosts the chances of pregnancy, explains Casper. Also, research has linked a vitamin D deficiency with lower pregnancy rates.

If multiple attempts to treat or improve your own eggs don’t lead to positive results, Baratz believes that the next course of action would be to look into donor eggs.


This article was originally published on May 10, 2016

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