The human egg cell explained for egg donors

The egg cell, o ovum (plural ova), is the female reproductive cell, or gamete. During the egg donation process, egg donors donate their eggs cells for these to be fertilised by sperm from the male recipient; as a result, embryos usually develop. One (or possibly two) of these fresh embryos will then be placed into the recipient (the woman receiving the eggs), giving her a good chance of becoming pregnant.

What is the structure of an egg cell?

Above you will see a diagram that labels the main parts of the human egg cell, together with an illustration of a real human egg.

How big is a human egg?

The human egg, or ovum, is one of the largest cells in the human body. That said, it is still very small and measures approximately 0.12 mm in diameter. You would need 9 eggs to reach a millimetre in length, and if you laid 100 of them side by side they would sit on a line just 12 mm (1.2cm) long.

How are eggs produced?

Eggs are produced in the ovaries, which are normally situated towards the back of a woman’s abdomen below the kidneys. The eggs develop from tiny cells inside the ovaries, going through various stages of development – known as oogenesis – until they are released once a month during ovulation. Usually each ovary takes turns releasing eggs every month; however, if one ovary is absent or dysfunctional then the other ovary continues to provide eggs to be released.

Female reproductive system, ovaries

How many eggs are there in an ovary?

How does an egg develop?

At the beginning of each menstrual cycle, a group of 10-20 primary follicles begin to develop under the influence of Follicle Stimulating Hormone (FSH). By around Day 9 of the cycle, only one healthy follicle normally remains, with the rest having degenerated. On approximately Day 14 of the cycle, a surge of Luteinising Hormone (LH) occurs, which causes the mature follicle to ovulate approximately 24 – 36 hours later.

Ovulation process follicle ovum corpus luteum corpus albicans

What’s different in an egg donation process?

During egg donation, a donor is stimulated with a synthetic version of the naturally produced hormone Follicle Stimulating, in order to encourage the growth of the whole group of 10-20 follicles. This encourages all of the eggs to develop to the same stage of maturity as the one egg that would normally be released. Rather than let nature take it’s course, ovulation is triggered by medication and the eggs are surgically removed 36 hours later and placed in a dish in an incubator ready for fertilisation.

If you’re interested in learning more about egg donation and becoming an egg donor, register your interest here.

What is egg quality?

Egg quality means how capable an egg is of being fertilised and going through the developmental stages to form a viable embryo. This is largely determined by two factors: the number of chromosomes present within the egg, and the energy supply of the egg. As both of these factors tend to reduce over time, age is one of the biggest factors affecting egg quality in a woman, with the quality gradually declining as she gets older. This is the main reason that egg donors need to be below 35 years – the age when the egg quality begins to reduce. Other factors that affect egg quality are lifestyle issues such as smoking, drinking, drugs (medical or otherwise) and general health.

Donate eggs in the UK

When trying to conceive, a lot of women and couples are heartbroken to find they can’t without the help of an egg donor. Altruistic egg donation is a wonderful, generous and selfless act. It allows a chance to make a real and meaningful difference in the life of another; to give hope to those who have none and offer a precious, life-changing gift that will help make another family complete.

If you think you could help someone with the altruistic act of egg donation in the UK, register your interest.