If you’re worried about a missed period, you may suspect that pregnancy is the cause—but it isn’t always.
Your hormones are constantly responding to the world around you. If your menstrual cycle changes from the norm, your body may be trying to tell you something about your health. This means a missed or delayed period, even if it’s not pregnancy related, should not be ignored.
It’s important to educate yourself on the possible reasons for an absent period, so you can discern what is a cause for concern and what’s not. This will empower you to move beyond self-diagnosis to informed action.
So, you’ve missed your period? Here are nine possible causes and what you can do about it.
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1. You’re pregnant.
No birth control is perfect, so your missed period may point to pregnancy. As it turns out, many of the symptoms you experience before and during your period are similar to the symptoms of early pregnancy (such as breast soreness, nausea, fatigue, and bloating).
2. You didn’t ovulate.
Every so often, for different reasons your body may not release an egg that month. This is called anovulation, and it’s probably already happened to you (even if you didn't realize it). Anovulation is caused by an imbalance of hormones brought on by either a hormonal imbalance like PCOS or possible changes in diet, stress, or routine. Anovulation is fairly common occurring among 4% to 23% of regularly menstruating women.
While skipping ovulation and a period every once in a while can happen, you should visit your doctor if you skip more than three in a row. If you’re on hormonal birth control, you may be ovulating inconsistently or not at all.
3. It’s your hormonal birth control.
All the most common forms of hormonal birth control contain one or a combination of the following hormones. The first is progestin, present in all forms of hormonal contraception, and which is used to inhibit ovulation. This hormone may cause your period to become irregular, lighter, or stop altogether over time.
The second hormone is synthetic estrogen, which may be used in combination with progestin, and whose main function is to help create a predictable and monthly “withdrawal bleed.” This withdrawal bleed occurs instead of your period. One or both of these hormones may be at the source of your missed period.
4. Starting or stopping contraception
What’s more, starting hormonal contraception introduces new hormones into your body, and coming off it will suddenly remove them. These times of hormonal imbalance or withdrawal will often cause unpredictable bleeding for a few months. If you’re stopping hormonal contraception, give your body time to re-regulate and expect a few irregular cycles.
These are the most common types of hormonal contraceptives:
- The birth control pill, including the combined oral contraceptive (COC) pill and the progestin-only “mini-pill”
- The hormonal IUD (commonly known as Mirena)
- The hormonal contraceptive implant (commonly known as Nexplanon)
- Injectable hormonal contraception (commonly known as Depo-Provera)
- The birth control patch
- The vaginal ring
If you’re currently on hormonal birth control and worried it might be the cause of your missed period, check out our in-depth article on how birth control can affect your period.
5. You’re stressed, traveling, or not sleeping well.
Stress
If you’ve recently experienced a major life event, an increase in workload, or a strained relationship, stress might be at the root of your missed period. Stress, especially chronic stress, alters your hormones and can induce a physical manifestation of your fight-or-flight response. When this happens, your body delays or inhibits some of your physiological processes (like your menstrual cycle) for your survival. Once a significant stressor is removed, your period should return to normal.
Travel & Sleep
Travel or sleepless nights may also be the reason for your missed period. In fact, any significant changes to your schedule can throw off your menstrual cycle, which can lead to a delayed or missed period. With a little time and adjustment to a new routine, your body should return to normal, and that goes for your period too.
6. You changed your diet or exercise habits.
Diet
Significant changes in diet can mean changes in your hormonal balance, which can throw off your menstrual cycle. If you recently made a substantial change to the food you eat (such as cutting out an entire category of food or introducing a new one), your body may need time to adapt. Be sure to talk to your doctor about major dietary changes (such as Whole 30, Keto, Vegan, Paleo, Atkins, or intermittent fasting) to see if they are the right fit for your body and overall health.
It's also important to note that failure to take in enough calories over a long period of time can cause malnutrition. This will eventually result in irregular or skipped periods, or even the cessation of your period altogether. If you struggle with disordered eating or have been diagnosed with an eating disorder, this may be at the root of your missed period.
Exercise
Most of the time, beginning a new exercise routine won’t have an effect on your menstrual cycle. But if you’ve recently become a Crossfit fanatic, your missed period may be caused by this sudden change in your workout habits.
Pay attention if your period has suddenly become irregular or stopped completely. Your missed period may indicate that you’re not taking in enough nutrition to make up for the energy lost while exercising, causing your body to redirect any remaining energy away from “non-essential” biological processes (like ovulation) to essential ones.
Consider upping your daily caloric intake (with healthy foods) while maintaining your consistent exercise routine. Talk to your doctor about exercise habits that won’t throw your hormones out of whack and lead to other negatives like a slower metabolism, a breakdown of muscle, and loss of bone density. Keep in mind that a good balance of diet and exercise is different for every woman.
Unexplained weight changes
Large fluctuations in weight are usually caused by a recent shift in exercise or diet, which may lead to changes in your menstrual cycle. But if you have lost or gained any significant amount of weight with an unexplained cause, call your doctor. Other health factors may be at play.
7. You have a thyroid problem.
The thyroid gland is responsible for regulating many processes in your body, like your metabolism and your menstrual cycle. Both hyperthyroidism (producing too much thyroid hormone) and hypothyroidism (not producing enough thyroid hormone), can cause a variety of changes in your menstrual cycle, including lighter, heavier, irregular, or skipped periods.
If you suspect you may be suffering from a thyroid disease, look for changes in your menstrual cycle in addition to changes in the following:
- Sleep
- Weight
- Energy levels
- Heart rate
If these symptoms are occurring, it would be a good idea to contact your doctor.
8. You have PCOS.
Your missed period may point to Polycystic Ovary Syndrome (PCOS). PCOS is caused by a reproductive hormone imbalance, in which the ovaries produce an abnormal amount of androgens (male hormones). This imbalance may lead to anovulatory cycles or irregular spotting.
While irregular periods are one of the most common symptoms attributed to PCOS, they are just a symptom—not the cause of the problem. Oftentimes, there are other coinciding symptoms you should be aware of:
- Excess hair or hair loss due to high presence of testosterone
- Irregular periods, no periods, or changes in your menstrual cycle
- Cysts or bumps on the ovaries
Up to 20% of women worldwide have PCOS. If you think you might have it, schedule an appointment with your doctor to explore ways you can manage your symptoms.
9. You’re breastfeeding.
If you’re exclusively breastfeeding, you may not get your period for several months (or even a year) after childbirth. This is because breast milk production is stimulated by prolactin, a hormone that suppresses ovulation and delays the return of your period until prolactin levels subside.
Although many women don’t have a period for months while breastfeeding, every woman is different. Some factors that could affect when your period returns include:
- You breastfeed, but not exclusively.
- You use a bottle for some feedings.
- You start to wean your baby.
Keep in mind that even if your period hasn’t come back while breastfeeding, you could still become pregnant before the return of your first menstrual bleed. This is because the first time you ovulate after pregnancy will occur before your first period does or does not show up. If that happens, a home pregnancy test may be a good next step.
Otherwise, if your period doesn’t return for three months after you stop breastfeeding, it may be time to schedule a visit with your doctor.
Listen to your body.
Your missed period could be occurring for any number of reasons. From pregnancy, to diet and exercise, to medical conditions like PCOS, so it’s important to familiarize yourself with the possible causes.
Your menstrual cycle can be a powerful indicator of your health. Learn to listen to your body, and don’t hesitate to reach out to your doctor. If you are pregnant and need to process that news in a confidential, safe environment, book a free Clarity Coaching Session.