While it would be great if your period worked like regular clockwork, occasional period irregularities are actually pretty normal. "The average cycle is 28 days—that's 28 days between the first day of one period and the first day of your next period—but anywhere in between 24 and 31 days is considered normal," says Veronica Lerner, MD, assistant professor of obstetrics and gynecology at NYU Langone Medical Center.
If you’re noticing irregularities with your period, you might want to take a look at the potential factors below. Any of these could affect menstruation to varying degrees.
- Excessive exercise. If you exercise a lot, you may notice that your periods come less frequently and are less heavy. This happens in part because of the combination of rigorous activity, low body fat, and stress on your body. While exercise is great for you in general, try not to overdo it! If your period is delayed more than three months, you should check in with your doctor.
- Being overweight. Excess fat cells can caused elevated levels of estrogen, which can affect how and when—and if—your ovaries release an egg. Of course, that affects your period, too. Over time, too much weight can increase your risk of endometrial cancer. If you’re having weight problems, try talking to your doctor or a nutritionist.
- Being underweight. Not weighing enough can cause period irregularities, too! This time the issue is that you’re not producing enough estrogen, as opposed to producing too much. If you’re just adjusting to some healthy weight loss, things should balance out in a few months. If irregularities last longer than that, though, it’s time for some professional help.
- Any medication that can affect hormones, such as thyroid medication, steroids, or antipsychotics, can influence your period. Be sure to get the details on any potential side effects when taking prescriptions so you know what to expect.
- Pesticides can act like hormones and also cause period irregularities. In fact, one study found that women exposed to pesticides were 60-100% more likely to have long cycles, missed periods, and spotting. One solution may be to go organic to limit your exposure to chemicals in your food.
There are a variety of reasons for period irregularities. In general, being off a month or two isn’t such a big deal. But if you’re really concerned, or think any of the above might be an issue for you, you should definitely consult your doctor.