9 Things No One Ever Told You About Your Ovaries


The human body is a strange and wonderful thing — but a lot of us aren’t super well versed in some of the more interesting things it can do. If you happen to have ovaries, for example? Well, let’s just say that there are a lot of weird facts about your ovaries that I’d be willing to bet no one ever told you — and that you probably didn’t even know to ask. That’s certainly been the case for me; luckily, though, one of my favorite things to do is research stuff I don’t know enough about. Come — let me share with you the fruits of my labor. It’ll at least give you a starting point for anything else you might want to know about your ovaries.

You probably have a general idea of what ovaries are for: They house eggs, giving them a safe place to hang out while they mature. When you ovulate, they launch a mature egg into your fallopian tubes for the purposes of fertilization. If the egg isn’t fertilized, then it passes through the uterus, while the uterus itself sheds the thick, nutritious lining it had previously built up in the event of egg fertilization.

But there’s a lot more to your ovaries than just that; from how they do what they do to what other factors can affect them, there’s a ton of info to learn about them. Here are nine facts about ‘em I’d bet no one ever told you:


They’re Not Always The Same Size

In fact, they change size — or, more accurately, volume — several times throughout your lifetime. According to a recently-developed model that was published in the journal PLoS One in 2013, 69 percent of the variation in ovarian volume is due to age: When you’re a very small child, their volume is usually around 0.7mL; the peak volume is 7.7 mL, which hits at around the age of 20; and after that, the volume declines again, usually measuring around 2.8mL by the time you hit menopause.

However, your ovaries changing size might also be an indication of a larger health issue. For example, ovarian volume may be used to diagnose ovarian cancer or endocrine issues and disorders like polycystic ovary syndrome (PCOS). Never underestimate the worth and importance of getting regular exams.


They Can Be Affected By Stress

If you’re stressed, your ovaries might be stressed, too — and that can have an effect on how they operate. As infertility specialist and vice chair of women’s health at Wake Forest Medical Center Sarah Berga, MD recently put it to WebMD, “We know now that stress hormones such as cortisol disrupt signaling between the brain and the ovaries, which can trip up ovulation.” If you're stressed, your ovaries might stop releasing eggs for a while. Just, y'know... FYI.


Your Ovaries Produce A Whole Bunch Of Different Hormones

They’re not just responsible for making estrogen; they make tons of different hormones, including progesterone, testosterone, relaxin, inhibin, and not one, but three types of estrogen — estradiol, estrone, and estriol. Each of these hormones plays a different role; some help your body develop during puberty, while others ensure fertility and/or prepare your body for giving birth if you get pregnant.


That Whole Thing About People With Ovaries Being Born With All The Eggs They’ll Ever Have Might Be A Myth

For many, many years, prevailing knowledge has stated that people with ovaries are born with all the eggs they’ll ever have — usually around two million to start, with the number of eggs actually stored decreasing to around 400,000 by puberty. Somewhere in the neighborhood of 400 to 500 of these eggs will fully mature and be released during ovulation.

However, in 2012, research into stem cells discovered that it might be possible for ovaries to generate more immature egg cells. The study focused on mice, and it hasn’t been replicated with humans yet — but still. If it pans out, one of the most commonly believed “facts” about ovaries might turn out to be a myth after all.


We Have No Idea Why Ovaries Release Some Eggs But Not Others

Each month, right after your period starts, your ovaries start growing follicles that are capable of becoming mature eggs ripe for releasing. Only one egg ultimately becomes what egg freezing service Extend Fertility delightfully calls the Queen Egg, however — the one that actually gets released from the ovary during ovulation. But as CBS News noted in 2011, we still don’t know why the Queen Egg (or Royal Egg, if you prefer) actually becomes the Queen Egg. It’s one of the most enduring mysteries about human reproduction.


Your Right Ovary Is More Likely To Release Eggs Than Your Left One Is

Assuming you have two ovaries, of course (not everyone does). We don’t know exactly why that is, either, but we think it has something to do with the differences between the left and right side of the reproductive system. Regardless, though, multiple studies have shown that right-sided ovulation occurs more frequently than left-sided ovulation. There also isn’t really a pattern when it comes to which ovary releases an egg each month — research has shown that the previous month’s ovulation side has no bearing on the next month’s.


Sometimes You Can Literally Feel Your Ovary Releasing An Egg

It’s called mittelschmerz, or “middle pain” in German. Not everyone experiences it, but when it happens, it’s usually about 14 days before you actually start bleeding. That’s when the ovarian follicle in one of your ovaries ruptures and releases a mature egg. If you feel either a dull, cramp-like pain or a sudden, sharp pain on one side of your lower abdomen at about that time, it’s probably mittelschmerz.


Ovarian Cysts Are More Common Than You Think

According to the National Institutes of Health (NIH), an ovarian cyst is usually defined as any ovarian follicle that’s grown larger than roughly two centimeters. They can be either quite small or quite large — but they’re not always a problem. In fact, they’re actually quite common: Per a 2018 study published in JAMA Internal Medicine, in a group of 72,000 people with ovaries who underwent a pelvic ultrasound between 1997 and 2008, about 23% of the participants under the age of 50 and 13% of those over 50 had a simple or functional ovarian cyst. What’s more, only one of those participants who was determined to have a simple ovarian cyst developed ovarian cancer. According to the Mayo Clinic, the majority of simple ovarian cysts disappear on their own without treatment. You might not even know you have one; it's a common experience not to notice.

Some cysts, however, can be indicative of bigger issues, like PCOS or cancer; the important thing to pay attention to is whether you’ve got any other symptoms. Pressure, bloating, swelling, pain, or in severe cases, sudden pain in your abdomen with fever, vomiting, dizziness, or fast breathing are all things to look out for. Especially if you experience any of those more severe symptoms, get yourself checked out ASAP.


Taking Oral Birth Control Can Reduce Your Risk Of Ovarian Cancer

According to a systematic review and meta-analysis of the literature pertaining to the relationship between oral contraceptive pills and ovarian cancer published in the journal Obstetrics and Gynecology in 2013, people who take the pill for 10 or more years see a whopping 50% reduction in the incidence of ovarian cancer. What’s more, assistant clinical professor of gynecologic oncology Dr. June Y. Hou, MD at the Columbia University Medical Center told Health in 2018 that “that effect can last for 15 years after discontinued use.”

All of this is, of course, only scratching the surface of what there is to know about your ovaries; if you have any other questions, your OB-GYN will likely be happy to help out. Knowledge is power, after all — especially when it comes to your reproductive health.