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Ovulation is a normal part of the menstrual cycle and typically happens every month before a person’s period. But what does it actually mean? What are the symptoms, what’s really happening, and—most importantly—how does knowing more about it help you manage your cycle, family planning needs, fertility goals, and overall health? Let’s take a look.
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What is ovulation?
Ovulation is a normal phase of the female reproductive cycle. All parts of the reproductive system – ovaries, fallopian tubes, and uterus – play a role. Ovulation is the phase when the ovaries release an egg, which then travels along the fallopian tube and arrives in the uterus, ready to be fertilized by a sperm. If the egg isn’t fertilized within 1–2 days, it will disintegrate and later be released in the menstrual period.
Let’s dive into some more detail.
Ovulation and the reproductive cycle
The reproductive or menstrual cycle, which generally lasts about 28 days, is divided into four main phases: menstruation, the follicular phase, ovulation, and the luteal phase. These phases overlap and interact with one another.
Menstruation, when you have your period, occurs when your uterus sheds its lining. It can last up to a week, but there’s a wide range of normal. This is followed by the follicular phase. This phase actually overlaps with menstruation, beginning on the first day of your period and ending around two weeks later when ovulation occurs. During the follicular phase, your ovary pushes several eggs toward its outer edge in little sacs called follicles. One of these eggs will mature and be sent out of the ovary, which triggers ovulation (Holesh, 2021).
During ovulation, the mature egg travels along the fallopian tube towards the uterus, where it waits to be fertilized by a sperm. If it meets a sperm within 36 hours, the egg will be fertilized, and pregnancy will occur (Knudtson, 2019).
Meanwhile, the ovary is staying busy. Starting at ovulation and continuing for 14 days, the luteal phase occurs. This is when the ruptured spot on the ovary where the follicle released the egg is transforming into a corpus luteum, a hormone-releasing structure that plays a crucial role in enabling the body to become pregnant (Oliver, 2020).
If a sperm doesn’t fertilize the egg, the whole cycle will reset when the luteal phase ends. The corpus luteum will break down, the egg will disintegrate, and all are released during menstruation, after which the cycle starts again.
How your hormones make ovulation happen
The entire reproductive cycle occurs thanks to an elaborate dance of hormones. There are four key players: follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone, and estrogen.
Your brain begins to secrete follicle-stimulating hormone during your period. As the name suggests, FSH stimulates your ovaries to start creating those little pouches (follicles) that will start moving eggs along and help them begin maturing. One of these follicles generally becomes strongest and rises to the top, and once that happens, it starts to create estrogen. The uterus is highly sensitive to estrogen, so once the follicle starts boosting these levels, the uterus responds by plumping up its lining to make it more welcoming for a fertilized egg to implant (Holesh, 2021).
When estrogen levels get high enough, the brain is triggered to cause a dramatic spike in luteinizing hormone (LH). Sudden high levels of LH are what triggers ovulation, and that dominant follicle in the ovary can send its egg out into the world to be fertilized (Reed, 2018).
Remember the corpus luteum? That ruptured follicle that released the egg is now starting to pump out progesterone, which peaks about halfway through the luteal phase, and more estrogen. If the egg is fertilized, progesterone helps it to survive and implant itself in the uterus so that pregnancy can continue. If the egg doesn’t meet a sperm, the corpus luteum begins to break down, and progesterone and estrogen levels begin to dip. Once they get low enough, menstruation is triggered, and your period begins (Oliver, 2021).
Ovulation signs and symptoms
So what does this all mean for you and your body? Thanks to the hormonal jamboree your body is experiencing, ovulation can come with some clear physical signs, as well as some uncomfortable symptoms:
- Increased discharge—You may notice your vaginal discharge (also known as cervical mucus) become clear, slippery, and stretchy when you ovulate. It’s one of your body’s ways of rolling out the red carpet for any sperm that might be introduced, helping make their journey to the egg easier (Ecochard, 2015).
- Temperature changes—Another sign of ovulation is a change in body temperature. Right before ovulation, your body temperature will reach its lowest point of the month, and right after ovulation, your body temperature will spike to its highest point of the month (Ecochard, 2015).
- Changes in sex drive—Some people report increases in their sex drive around the time of ovulation (Faust, 2019).
- Spotting—Up to 13% of women experience light bleeding during ovulation. This is generally normal and only lasts for a few days. It can also be a side effect of hormonal contraception (Dasharathy, 2012).
- Cramping—We don’t fully understand why, but many women experience some pain with ovulation. Called “mittelschmerz” (the German word for “middle pain” since it is felt in the middle of the cycle), this cramping tends to be mild, one-sided, or in the lower abdomen, and resolves after a day or so (Won, 2010).
- Breast tenderness—Thanks to hormone fluctuations, you also may find your breasts feel swollen and tender during ovulation (Faust, 2019).
What to know about a sudden change in menstrual cycle length
When does ovulation occur? How long does it last?
It varies from person to person, but ovulation occurs roughly two weeks from the start of menstruation. This is at the end of the follicular phase (when the ovary is getting ready to release that month’s egg) (Holesh, 2021).
Ovulation is the shortest phase of your cycle—it only lasts for around 36 hours. This means that the egg is available to be fertilized only for this period of time (Knudtson, 2019).
Ovulation, pregnancy, and contraception
Understanding ovulation can be a valuable tool, both for people trying to get pregnant and those trying to prevent it.
You may think that since ovulation only lasts for 36 hours, you can only get pregnant during that exact timeframe. But this isn’t quite the case. It’s true that the egg is only available to be fertilized by a sperm for 36 hours, but sperm can actually survive in the reproductive tract for up to five days. In other words, if you have sex five days before you ovulate, those sperm could still be able to impregnate you (Su, 2017).
This means that people seeking to become pregnant have roughly a one-week window in which sex could result in pregnancy. Conversely, it means that people seeking to avoid pregnancy must ensure they are using effective contraception for that week. For both groups, the important and tricky part lies in identifying when ovulation is going to happen—before it starts.
How to track ovulation
Tracking ovulation empowers you to either avoid becoming pregnant or to increase your chances of becoming pregnant. It’s not an exact science—though technology is improving—but with a little practice, tuning in to your body’s signals and estimating ovulation can be a simple process.
Basal body temperature
Ovulation is bookended by two big changes in your body temperature (called basal body temperature, or BBT): it dips right before ovulation and peaks right after ovulation.
In terms of planning or avoiding pregnancy, BBT tracking is a way of identifying when you ovulated (after the fact). Because it only shows you after you’ve ovulated, it is not a reliable contraceptive method on its own. BBT involves taking your temperature every morning before doing anything—including before getting out of bed, having sex, or getting up to use the bathroom—and keeping track of those morning temperatures (Su, 2017).
Once you have a month of temperatures, you can simply look at the numbers or map it out on a simple graph to pinpoint what day your temperature spike (and therefore ovulation) happened. There are a number of tools and apps that can be used as well. If you keep it up diligently, after a few months, you may be able to reliably tell what day of your cycle you will likely ovulate. This is an especially helpful tool for women with regular monthly periods; it may be less reliable for those with irregular periods (Su, 2017).
Another physical change you can easily track in your body is your cervical mucus (vaginal discharge). This may seem like an unappealing prospect at first, but it is quick and simple to get the hang of and can be a very reliable indicator of ovulation. During ovulation, the discharge that comes from your cervix and out through your vagina becomes slippery, clear, and stretchy—similar to the consistency of raw egg whites. You can check your cervical mucus before going to the bathroom by gently wiping with clean toilet tissue and observing what the consistency is.
Tracking your BBT and cervical mucus together is a fertility awareness method of family planning known as the “symptothermal method.” Using this method, you can estimate when your “fertile days” are and use contraception accordingly (if you are trying to avoid getting pregnant). When done correctly, it’s a highly effective method; one study that assessed its effectiveness as a contraceptive method found that the failure rate (or rate of unintended pregnancy) was only 1.8% (Su, 2017).
Cervical mucus: different types and what they mean
Apps and ovulation calculators
There are a variety of mobile apps and tools available to help you track your cycle and enable you to either seek or avoid pregnancy. Some of these can be as effective as traditional methods of tracking ovulation. One study that evaluated nearly 100,000 women found that the self-reported data from those who used apps to track ovulation were consistent with traditional methods of tracking ovulation (Faust, 2019).
However, if you decide to use an app-based tool to help you track your ovulation, try to find one that uses your own body’s information and signals. For example, some apps help track and evaluate your BBT information (Su, 2017). Others use generic and averaged statistics which may or may not apply to your body and unique cycle and could result in inaccurate predictions of fertile days (Johnson, 2018). Using an evidence-based tool will increase its effectiveness and accuracy more than apps that roughly estimate when ovulation will occur.
Ovulation predictor kits
Over-the-counter ovulation test kits are widely available tools for predicting ovulation. They generally work by assessing levels of LH in the urine. Because an increase in LH comes a few days before the egg is released, it can help a person know that ovulation is likely to occur soon (Su, 2017). However, because they only predict ovulation a few days in advance, they are more likely to be useful for people seeking to get pregnant than those tracking ovulation for contraception. (Remember, sperm can survive for five days waiting for ovulation).
Issues with ovulation
Ovulation requires harmony between many factors within your body; it’s a function of your hormones, brain activity, nutrition, stress levels, and even your physical fitness (Sharma, 2013). Sometimes one or more of these factors will be out of balance, and ovulation can either be prevented or impacted in some way.
Signs of an abnormal menstrual cycle—and potentially an issue with ovulation—include irregular bleeding (unrelated to hormonal birth control) and irregular or skipped periods (Rasquin, 2021). Talk with your care provider if you are experiencing these symptoms, and you can more accurately understand your personal situation as it relates to ovulation and seek medical care if needed.
A range of medical and lifestyle factors can affect a person’s ovulation.
Because the correct ebb and flow of hormones play such a key role in ovulation, a medical condition that imbalances these hormones can interrupt or prevent ovulation. One such condition is hypothalamic dysfunction (when the hypothalamus gland, one of several hormone-releasing systems involved in ovulation, is not working correctly) (Mikhael, 2019). Another condition is polycystic ovarian syndrome (PCOS), a common hormonal disorder that often prevents women from ovulating. Fortunately, such conditions have a range of treatment options available (Tanbo, 2018).
Stress is a normal part of daily life, but excessive stress can negatively impact your health, including ovulation and fertility. Stress hormones can prompt a fight-or-flight response from your body, and it’s possible that this may signal to your body that the time is not right for pregnancy (Sharma, 2013).
This is a complicated and tender issue for many couples striving to become pregnant, and there is much we still don’t know about the relationship between stress and fertility. However, there are many tools and resources are available to help support you both physically and mentally if you find that excessive stress is affecting your daily life or your fertility goals.
Exercise, weight, and fertility: what’s the connection?
Carrying too little weight (especially as a result of eating disorders) can have a host of negative impacts on your body, including preventing ovulation from occurring. Similarly, elite athletes can also disrupt their hormonal balance and reproductive cycles with the high energy demands and reduction in body fat that come from excessive exercise (Sharma, 2013).
Hormonal birth control
Many types of hormonal birth control function by intentionally suppressing ovulation. There is no medical issue with this—indeed, many types of hormonal birth control are associated with reduced risk of reproductive cancers and pelvic inflammatory disease. But if you are interested in tracking your ovulation and are taking a form of hormonal birth control, double-check that your method isn’t preventing it from occurring (e.g., birth control pills and hormonal IUDs) (Sharma, 2013). If you are interested in tracking ovulation but still want to use a highly effective and long-term contraceptive method, a non-hormonal method like a copper IUD may be an appropriate option.
Learning about ovulation and better understanding your own body’s unique cycle can empower you to participate more effectively in your family planning goals and know your body better. Whether you’re trying to get pregnant, trying to avoid pregnancy, or just want to understand what’s going on in your uterus every month, learning to pick up on your body’s signals of ovulation can be a great place to start.
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Dr. Steve Silvestro is a board-certified pediatrician and Manager, Medical Content & Education at Ro.