If you're a menstruating person, then you already know that far too much of life is spent waiting for late a period to show up. It can be one of the most infuriating things, especially if you've already been battling annoying PMS symptoms for a while, like bloating, fatigue, and bizarre food cravings. When your period finally does arrive, though, most of us don't even bother to poke around and find out what the reason for our period being late was. I know I don't — I'm just so happy to finally see red that I celebrate briefly, grab my menstrual cup, and happily move on.
But it might be worth our time to dig a little deeper and understand what's responsible for a late period. In some cases, it might point to a health issue that has been previously overlooked. Other times, it could be something harmless, but knowing about it can help us prepare better so we don't have to play the anxious waiting game again in the future. Bustle spoke with Anna Druet, a Research Scientist at Clue, the free app that allows you to track your menstrual cycle, who says there isn't ever one single answer to why our periods are late. "Every cycle is unique, and some are more sensitive to changes in things such as sleeping patterns and eating habits," she says. That's why it always helps to keep track of when your period normally comes and ends, so when something seems off, you can take note of it and see if it's worth looking at with your doctor.
But what's "late," exactly? A run-of-the-mill menstrual cycle generally falls between 21 and 35 days, but it's different for every woman. However, you should have consistency in whatever number of days your cycle is — that's what makes a "normal" period. If your period is five or more days late, something is probably going on, even if it's nothing too serious. Finally, if you're keeping track of your cycle and see that three or more months in a row have been irregular, call up your provider and see if you can schedule an appointment to uncover what's going on.
Here are eight reasons your period might be late that you probably haven't considered.
1. You Recently Took An International Flight
This is a sneaky one that most of us never consider. A few months ago, I took an international flight — and my next period was 10 days late. I had no idea that my cycle had anything to do with traveling, so that week and a half was the most worrisome time of my life. Druet assures me this isn't uncommon, though. When we travel across time zones, "the loss or gain of hours... affects your circadian rhythm, which in turn influences the hormones that regulate your menstrual cycle," she says.
Because our circadian rhythm is intimately connected with our menstrual cycles, it could take a period or two before your hormones are back in balance with the time zone you've settled into. So don't be surprised if your period decides to be extra stubborn when you and your bestie take that trip to Europe you've been planning for a while. "Also, be aware that your fertile window may be different," Druet advises.
2. You're Extremely Stressed Out
Stress takes a toll on the body, particularly when we experience it in large quantities. According to Dr. Lauren Streicher, associate clinical professor OBGYN at Northwestern University, stress can throw off the healthy connection between our pituitary glands and our ovaries. Dr. Streicher told Buzzfeed that an off-kilter ovulation cycle affects your menstrual cycle as well, likely making your period come a bit later than usual. (Keep in mind, though, that if you're on a hormonal form of birth control, this won't be the case, since the contraception you're taking will guide your menstruation, not your ovulation.)
If you're going through a particularly stressful time, like a breakup or starting a new job, your period may decide to hold off on you for a little while. If this keeps happening for a while, though, you might be chronically stressed out, which means you should consider making some lifestyle changes or at the very least, go see a doctor. Letting this kind of heavy stress take over may result in amenorrhea, which is the loss of your period entirely.
3. You've Gained Or Lost A Significant Amount Of Weight
Extreme changes in your weight and BMI can easily affect when your period is arriving. We're not just talking the few pounds you put on during your vacation; if your BMI falls below 18 or 19, for example, your period might be arriving later than normal, and you may even start missing periods altogether. Similarly, a sudden weight gain could result in irregular periods as well, as your ovulation will probably be affected by the sudden bodily changes. Speak to your doctor if you've recently gone through some physical transformations that you think are affecting your menstrual cycle.
4. You're Sick, Or You Were Not Long Ago
Things like the flu or a stomach virus may not hurt you in the long run, but they could have an impact on your next menstrual cycle. Your body simply doesn't function the same way when you're feeling sick. If you're experiencing noticeable changes in your digestion and respiratory health, chances are your reproductive system has taken a hit, too. It's nothing to worry about, really, and you should be back to normal when you start feeling 100 percent again. (Like stress, this only applies to you if you're not taking hormonal birth control.)
5. You've Recently Experienced Significant Changes In Your Life
Druet tells Bustle that changes in sleep patterns or work hours can affect your menstrual cycle, just like international travel can. Moving to a new location may have an impact as well, especially if you've relocated from the West to the East Coast. This "will have a greater impact on your cycle as it is harder for your body to adjust to losing time," Druet says.
No matter how minor you think the changes in your life may be, remember that your menstrual cycle doesn't exist exclusively on its own. It's affected by the rest of your body and the myriad of your lifestyle choices, since they all have an effect on the balance your hormones.
6. You've Been Exercising Excessively
Before you cancel your gym membership, know that the definition of excessive exercise doesn't simply mean you've run a few extra miles on the treadmill and exhausted yourself. This term generally applies to serious athletes and people who are training for marathons. If you've recently beefed up your exercise regimen, your body may react to the sudden changes, potentially resulting in late periods or no periods at all. This happens because the stress you put yourself through with such rigorous exercise causes your body to do anything it can to prevent pregnancy. Ovulation gets thrown off, you have less estrogen in your system, your uterine lining doesn't thicken, and subsequently, your period may be a bit tardy.
Nichole Tyson, M.D., OBGYN and Director of Pediatric/Adolescent Gynecology at Kaiser Permanente in Northern California, told Seventeen that the amount of exercise each of us can handle until our menstrual cycle responds varies in every person. It all depends on our unique body type and personal health.
7. You Just Changed Or Stopped Using Birth Control
If an imbalance in your hormones causes a late period, you can bet a change in birth control methods can cause a delayed period. When you start a new regimen of contraception, your hormones need time to adjust and introduce your body to a cycle. It's just as probable that you see odd delays in your period when you choose to quit your birth control as well; your body is recalibrating to its own rhythm, so give it some time to fall back into the swing of things.
8. You Have An Illness Or Disorder That Hasn't Been Diagnosed Yet
Having late or irregular periods can be a sign that something more serious may be going on. One potential cause is an overactive thyroid, which causes delays in menstruation, a strangely light flow, or skipped periods altogether. Non-period related symptoms that point to a thyroid issue include diarrhea, muscle weakness, sudden weight loss, and a racing heart. Another reason could be polycystic ovary syndrome (PCOS), a hormone imbalance that sends abnormal levels of estrogen, testosterone, and progesterone through the body and causes lack of ovulation. Other symptoms are infertility and the growth of hair in odd places, so if you've encountered any of these, speak to your doctor. PCOS may sound highly unpleasant, but there are plenty of ways to treat it safely.
It sounds strange, but chronic disorders like celiac disease could even be causing your late or irregular period. Alyssa Dweck, M.D., assistant clinical OBGYN professor at Mt. Sinai School of Medicine, told Women's Health that this disease, which causes a severe gluten intolerance, can wreak havoc on your entire system and consequently mess with your menstrual cycle.
The Bottom Line
If any of the above sounds familiar, it's best to schedule a visit with your doctor and see if you should get tested for any hidden illnesses you have yet to uncover. Our bodies are not such simple things to understand, so it could be a collection of things happening internally that are causing your late period. Keep in mind no matter what, though, that three consecutive months of irregular periods probably points to something more than just jetlag. Don't hesitate to speak with your provider — because, as annoying as our periods can be sometimes, they're a pretty good indicator of what's going on with the rest of our health.
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