How Egg Quality Is Related to Chromosomal Abnormalities

egg quality related to chromosomal abnormalities

Whether a woman is pregnant through natural means or in-vitro fertilization, one of the key determinants of birth rate is the health of the developing fetus. This, in turn, is affected by embryo quality, which is dictated by genetics. Chromosomal abnormalities can be incompatible with life, resulting in miscarriage and other complications; and can be affected by the quality of the egg even before it is fertilized.

Not withstanding other causes of infertility, such as reproductive tract abnormalities or male factor infertility, attempts at fertilization using in-vitro fertilization or by normal sexual intercourse have similar end results,
and a woman with poor egg quality would have any of the following:
1. No fertilization.
2. Fertilization, but no implantation due to poor embryo quality.
3. Implantation, but chromosomal abnormalities result in miscarriage.

Female age is one of the most important factors in estimating the probability for pregnancy, and a woman’s egg quantity, or ovarian reserve is the supply of follicles she has at birth. As a woman gets older, her ovarian reserve diminishes overall, with some variation in the degree of this decrease on a year-to-year basis.Ovarian reserve begins to decrease when a woman is in her early 30s, and her fertility potential declines more rapidly as she approaches 40 years of age.

For women undergoing IVF, the number of eggs obtained is strongly correlated with the chance for success. More eggs overall indicate more healthy eggs, even though they may represent a low proportion of the total egg supply.

Currently there exists no test that screen for egg quality. However, the age of the female is the best and most important indicator for this. Female age is correlated with the chances of chromosomal abnormalities in the eggs themselves, since these abnormalities increase significantly as women get older. Ovarian reserve testing, which includes antral follicle counts via ultrasound, day 3 FSH testing, and Anti-Mullerian Hormone levels can render the quantity of eggs, allowing the fertility therapy specialist to estimate the chance of success.

It is important for women to understand that their menstrual cycles have very little to do with the health of the eggs themselves, whether they get their periods every month, or have irregular menses, or even if they have painful symptoms while on their periods. Poor egg quality does not cause dysmenorrhea or have an effect on menstrual cycle, and does not manifest with clinical symptoms. Thus it is important for women dealing with infertility to undergo ovarian reserve testing.