We always hear about how interesting men’s sperm are – how quick, agile and strong they are, able to traverse the long journey to the egg, but how much do we know about the other genetic half of a child – the female egg?
In writing this article, I came across some really interesting information about human eggs that I think we should all know! Read on to learn some of the most fascinating facts about human eggs, and the intricate processes of ovulation and conception.
1. Women May Be Making New Eggs Throughout Their Lives
For a long time, biology books have stated that a woman is born with a finite number of eggs – that the production of a woman’s eggs happens entirely in-utero, and ceases before birth. It is usually reported that a woman has 7 million immature eggs when she is in her mother’s womb, and that this number drops to 700,000 by the time she reaches puberty.
But in 2012, a research team from Massachusetts General Hospital, Harvard Medical School and Saitama Medical University, Saitama, Japan, turned this theory on its head. Scientists have discovered a new type of stem-cell in the human ovary that may point to the possibility of new eggs continually being formed throughout a woman’s reproductive years. Since men are constantly making new sperm (about 1,500 every second!), it shouldn’t be such a stretch to consider that women may be producing new eggs throughout their lives as well. Further research will be able to confirm this new theory, and continue expanding our view of women’s fertility.
2. A Human Egg is Remarkably Big
You might be surprised to find out that the human egg is one of the biggest cells in a woman’s body. It is about the size of a grain of sand and can actually be seen with the naked eye. To put this into perspective, an egg is about 4 times bigger than a skin cell, 26 times bigger than a red blood cell, and 16 times bigger than a sperm!
3. An Egg Takes a Long Time to Mature
Most eggs are present within the ovary in an immature state from the time of a woman’s menarche. Some eggs will lie dormant for years or even decades before they begin to mature, while others will degenerate and never develop. For eggs to complete their journey to ovulation, they receive a signal to begin their final maturation process about 150 days before they would be released from the ovary. At the beginning of any given cycle, there are generally about 12 eggs that have started to grow, and as ovulation nears, preference is given to one of those eggs, as it receives the final push to maturity and is then released from the ovary.
4. The Egg Has a Short Life After Ovulation
Once the egg has matured and is released from the ovary during ovulation, it goes into the fallopian tube where it lives for 12 to 24 hours. Conception is possible if sperm is already present in the fallopian tubes when the egg is released, or if a woman has sex while the egg is alive, causing sperm to swim up through the uterus and into the fallopian tube. Sperm can reach the egg in as little as 30 minutes. If conception is successful, the newly fertilized egg will travel down the fallopian tube and implant into the uterus 6 to 10 days later. If the egg is not fertilized, it will simply dissolve and pass out with the menstrual flow.
Though the egg has a lifespan of less than a day, sperm can stay alive inside a woman’s uterus and fallopian tubes anywhere from 1 to 5 days. This means that sex up to 5 days prior to ovulation can actually result in pregnancy–but it is exceedingly rare for a sperm to survive more than 48 hours! However, the 2 days before and the day of ovulation are the most fertile days of each cycle. The lifespan of the sperm is dependent on the sperm’s health, but also on the woman’s cervical fluid, which can nourish the sperm during its wait.
5. The Egg is Quite Picky
When discussing fertilization, the egg is often portrayed as a passive player in the drama of conception, waiting patiently for the first sperm to arrive and burst in. But research from the late 1980s out of Johns Hopkins, the University of Wisconsin and the Roche Institute of Molecular Biology has shown that the egg has a much bigger role than previously thought, and that she is in fact quite picky! Although we usually think of the sperm doing all the hard work of fertilization, penetrating the docile egg, it is now believed that the egg actually chooses who she lets in or not.
The egg appears to give preference to sperm with intact DNA, producing a compound that softens the outer layer of the egg to allow specific sperm to enter. These studies also suggest that the egg may even actively bind sperm to its surface, thereby not giving the sperm any choice in the matter, trapping the sperm it has chosen. Once a sperm has made its way in, the outer layer of the egg hardens, which prevents entry to any other suitors.
6. Multiple Ovulation is More Common Than You Think
Multiple ovulation is the release of two or more mature eggs during a cycle. This is said to occur in up to 10% of all cycles, which means that the average woman releases two (or more) eggs at least once a year! When 2 eggs are released and both are fertilized, this produces fraternal twins or non-identical twins if they both implant. Identical twins are produced when a single embryo divides into two.
It is important to note that whenever double ovulation occurs, it happens as part of a single ovulatory event – the eggs will be released within a 24 hour period. That delay became known from the remarkable event whereby one mother gave birth to twins each one from a different father. Once ovulation occurs, there is a big hormonal shift that takes place, progesterone production is revved up, and the release of any future eggs is halted. Therefore, it is not possible for a woman to ovulate on Monday and then ovulate again on Saturday.
About the Author:
Kathryn Cardinal is an herbalist and Fertility Awareness teacher. She is passionate about working with women to help them reconnect to their sacred womb wisdom and achieve radiant health naturally. Kathryn’s work focuses on holistic hormonal health, natural contraception, and conscious conception. More information can be found on her website, www.springmoonfertility.com
- White, Y., A.R. et al., (2012) Oocyte formation by mitotically active germ cells purified from ovaries of reproductive-age women. Nature Medicine 18, pp. 413-421. doi:10.1038/nm.2669. Retrieved from: https://www.nature.com/articles/nm.2669
- Freedman, D.H. (1992) New Theory on How The Aggressive Egg Attracts Sperm. Discover Magazine. Retrieved from: http://discovermagazine.com/1992/jun/theaggressiveegg55
- Weschler, T. (2006) Taking Charge of your Fertility, 10th anniversary edition. Collins. New York, NY.
- Singer, K. (2004) The Garden of Fertility. Avery. New York, NY.
- Cell Size and Scale. Retrieved from: http://learn.genetics.utah.edu/content/cells/scale/
Kathryn Cardinal is a Certified Herbalist and Certified Women’s herbal educator taught by Aviva Romm MD. Since 2009 she has been teaching classes, workshops, and working 1 on 1 with women to help them balance their hormones, overcome health challenges, and get pregnant naturally. Kathryn has overcome unexplained infertility and several miscarriages through her natural practices, and is now has 2 children of her own.
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I am 27 and in good health. But I have never had regular periods which i guess begs to question how healthy I really am. But my husband and I have been trying for 2 years but I haven’t had a period since Dec. of 2016. I have had labs ran and they say everything is withing normal range. I have researched alot and I possibly could have PCOS two of my sisters have it. But I’m not sure. I don’t have pain/cramps or breakouts. I’m 5’1 140 (I have alot of muscles from sports) and live a pretty healthy lifestyle. Do you have any advice?
Dear Abigail,
I’m glad you reached out for support. My first thought is, are you ovulating? I venture a guess not, but wanted to ask if you know. My second thought is, could you be too healthy? That seems super silly to even read, I know! But what we know is that women to are super or chronic exercisers, with low BMIs, who eat little healthy fat, often have irregular and sometimes absent menstrual cycles. Could this be the case for you?
May I know what labs were run? What were your cycles like when you had them?
It would help me to get to know more about you in order to offer advice. If you’d rather share in a direct email, contact me here…
This is such an interesting article. I am trying to get pregnant but not getting my menstrual cycle. I do have one child and at that time I wasn’t getting it either but managed to fall pregnant.
Dear Lisa,
Some women to ovulate (sometimes not regularly though) even though they do not have a period.
Do you know why you aren’t menstruating? Have you had testing to determine the cause? May I know how old you are?
Hi,
I have two questions.
1 If my period starts today. Does that mean my eggs was dissolved 24 hours ago. Or the egg dissolve in 24 hours but my period won’t start in 2-4 days later?
2. In a cycle, one out of 12 eggs will mature then the rest (11) died so Batch 1 is done. Then a new cycle begins, Batch2 with 1 out of 12 eggs will mature and 11 will died. When 11 eggs died, do they dissolve in the ovaries?
Thanks
Hello QQ!
One of the ovaries will ovulate one egg mid-cycle. Typically ovulation happens about two weeks after the first day of a period (which is cycle day 1). If the egg isn’t fertilized by a sperm, the egg will dissolve 24 hours after ovulation somewhere in the fallopian tube most likely. Any eggs that weren’t fully mature to ovulate (I can’t know if that is for sure 11 others) will dissolve in the ovary or perhaps remain for the next cycle is my understanding. So, the egg that was ovulated mid-cycle if you do not conceive has been dissolved for several days before your period starts.
Very informative article. Also useful for women who want a baby. Thanks for sharing !!!
Just to clarify, once the egg has reached the end of it’s lifespan is there any possibility of become pregnant AFTER that if you have intercourse, even though the egg has dissolved?
Dear Rivella,
If the egg has dissolved, it is gone. So, there isn’t a change of conceiving that cycle. The next chance would be the next time you ovulate, perhaps the next cycle.
Great article! Will be sharing 🙂
That is so interesting. Thank you. I wish my eggs will just let the sperm in now and stop being too picky…I want to fall pregnant.
Hi Kathyrn! Thanks for this informative piece you have put together. I have been ttc for 7 months. I noticed I don’t get EWCM during ovulation, but I ovulate because I use the test strip and also get the pain in my right pelvic area. I have taken Evening Primrose Oil and Robittussin for a month, but I didn’t have any change. My cervical fluid is much, white and slippery, stretches a little and break. I just started another cycle. I need advice on what to do to get EWCM as ttc is becoming frustrating. HELP!
Dear Loveth,
We are thankful our guest author’s article has been helpul!
What you have described actually sounds like fertile cervical fluid (mucus). This mucus is what is felt externally and can be seen in undies. While it too feels “wet”, it is more pliable or stretchy and egg-white like (although it can be cloudier or more creamy than actual egg whites… each woman’s fertile cervical fluid will vary some). If interested, click to following link to learn more about how to naturally Increase Cervical Mucous to Get Pregnant.