Eggs and fertility
The other day a patient brought me a wonderful gift. She lives in a rural area of Los Angeles where she raises a few chickens and cultivates a lovely garden. The gift included 6, beautiful, fresh chicken eggs. Each was smooth and perfectly shaped with subtle hues of brown, green and blue that one never sees in supermarket eggs. As each egg had it own unique shape, color and size, my patient could lovingly identify the hen from which it came. It truly was a fantastic gift, and in addition to making a hearty breakfast, it got me thinking about the wonders of eggs and how important they are to life as we know it.
Egg Size
Human eggs are astounding for a number of reasons. First of all, they are the largest cells in the human body. The diameter of an egg, or ovum, is about one tenth of a millimeter (100 microns). This is a little smaller than an average grain of sand and is right around the lower limit of what is visible to the naked eye. When an egg is ovulated, it is surrounded by a flock of supportive cells called cumulus cells which protect and nourish the egg on its way to becoming an embryo. The diameter of the egg with its cumulus complex is close to .25mm and can definitely be seen with the naked eye in with the right lighting.
Egg supply
Human eggs are especially precious. We are born with all the eggs we will ever have for our entire lives, roughly 2,000,000 at the time of birth. That number diminishes as we age until the supply is exhausted at menopause. Importantly, there is a strong correlation between the number of eggs remaining in the ovary, and the chance that an egg will eventually become a baby. That is to say that as the number of eggs decreases, so does our ability to have a baby. This is the main reason why there is an age related decline in human fertility.
Egg Quality
Eggs in the supermarket are graded as AA, A, or B based on the thickness of the yolk, appearance of the white, and characteristics of the shell. Grading human eggs however, is much more complex. While many patients inquire about the grade, or quality of their eggs, the truth is that until an egg is fertilized, it is difficult to gauge its quality. Once fertilization is completed however, there are standardized methods to asses an embryos quality, or implantation potential.
Egg Testing
For women interested in knowing about their egg supply, some simple tests can give a good assessment. The antral follicle count is performed through ultrasound and gives and idea of the number of eggs available for IVF stimulation in a given month. FSH (follicle stimulating hormone) is a hormone produced in the brain which stimulates the ovary. If the FSH is elevated on the 3rd day of a menstrual cycle, it can mean that there are a diminished number of eggs remaining in the ovary. Lastly anti-mullerian hormone (AMH) is a hormone made by all the microscopic eggs in the ovary. If the muber of those eggs is low, so too will be the AMH.
If you have questions about eggs, fertility testing or anything else related to reproduction, feel free to contact us, we will be happy to speak with you.
