There are many reasons your period could be delayed. Everything from stress to serious illness can cause a late or skipped period.

You might have heard that taking antibiotics is one of those reasons. However, antibiotics aren’t one of the causes of a late period. So, if your period is late during or right after a round of antibiotics, they’re not to blame.

It’s not uncommon to experience a later than expected period after a course of antibiotics.

While it seems logical to assume the antibiotics are responsible for this change to the menstrual cycle, there’s actually no scientific evidence to back this up. In fact, scientific studies have shown that antibiotics don’t cause a delay or change to your period.

That doesn’t mean you might not have a delayed period after taking antibiotics. It just means the antibiotics aren’t the culprit. The truth is that many things can delay to your period. Often, these things are happening during the same window of time you’re on antibiotics.

For example, a delayed period can be caused by stress. If you don’t feel well and need antibiotics, you’re likely under stress. This can also put your body under physical stress, which may get worse if you need to miss work or cancel plans.

Even if you don’t feel stress, being sick enough to need antibiotics can be enough to throw your period off for a few days. So, the delay to your period is real, it’s just not being caused by the antibiotics.

Taking antibiotics doesn’t generally have any impact on your period. Only one antibiotic, rifampin, has been shown in studies to have any effect on your period. Rifampin is used as a treatment for tuberculosis. Other more common antibiotics won’t impact your period.

However, being sick and under stress may affect your period. You might see changes to your normal menstrual cycle including:

  • early periods
  • heavy bleeding
  • light bleeding
  • shorter periods

These changes aren’t caused by the antibiotics but can be caused by feeling unwell enough to need antibiotics.

In fact, the changes could be caused by other medication you’re using to feel better. Over-the-counter pain relievers like aspirin or ibuprofen can cause changes in your menstrual bleeding.

The only antibiotic that has been proven to make birth control less effective is rifampin.

Studies have shown that rifampin can alter the hormonal levels in your birth control which can make it less effective. Other antibiotics haven’t been shown to have any effect on your hormones, so they’re unlikely to have any effect on birth control.

However, some doctors believe that more research is needed on this topic. There may be still a risk. To make sure you’re protected, using a backup method of birth control while you’re taking antibiotics is a good idea.

There are a few medications that can cause changes, including delays, to your period. This includes:

  • aspirin and other blood thinners
  • nonsteroidal anti-inflammatory drugs (NSAIDs)
  • hormone therapy
  • thyroid medications
  • chemotherapy

Talk with a healthcare provider if you’re taking any of these medications and see a change in your period. In some cases, the change might be an expected side effect. It could also be a sign you need a different medication or different dose, so it’s a good idea to let a healthcare provider know.

There are a variety of reasons your period might be late. Fortunately, many of them aren’t a cause for serious concern.

You might have a late period one month, but then be back to your normal cycle next. However, a late period can be a sign of something more serious happening in your body, so it shouldn’t be ignored. Reasons you period might be late include:

  • Pregnancy. A late or missed period can signal pregnancy, but it’s far from the only cause. An at-home pregnancy test is a good place to start if your period is late and you think you might be pregnant.
  • Birth control. Birth control pills can change your periods. You might have late or missed periods, especially if you’ve recently changed your birth control.
  • Stress. Stress is one of the most common reasons your period might be late. Stress can lead to changes in the part of your brain that regulates your period. It can also lead to changes in weight, another common cause of late periods.
  • Body weight or weight loss. Weighing less or more than the recommended weight range for your height can cause your periods to be late or even stop altogether.
  • High levels of exercise. Training for a marathon or other intense sporting event can lead to late periods.
  • Polycystic ovary syndrome (PCOS) and other hormonal imbalances. PCOS can raise the levels of some hormones in your body, including androgen and insulin. This can lead to late or even missed periods. Other hormonal imbalances, including thyroid conditions, can also cause late periods.
  • Chronic conditions. Some chronic conditions, such as diabetes or Celiac disease, can cause you to have late or missed periods.
  • Menopause or early menopause. As you approach menopause, your periods may become less regular. If you’re younger than 40, missed periods could be a sign of a condition called early perimenopause.

While it’s rare, a late or missed period can also be a sign of ovarian cancer.

If you’ve been under extra stress lately, you might be able to get your period back on track by working on lowering your stress level. However, if you’ve had multiple late and unpredictable periods, it’s a sign to see a healthcare professional.

When to see a doctor if your periods are late
  • if your periods have stopped and you’re under 45
  • if you’ve missed three periods in a row
  • if you’re experiencing bleeding between your periods
  • if you’re experience bleeding after sex
  • if you’re experiencing sudden changes to your normal menstrual cycle
  • if you have reason to think you might be pregnant

The remedy for late periods depends on the reason behind it. Some steps you can take to stay more regular include:

  • reducing your stress levels
  • moderating exercise levels
  • maintaining your weight

While there are things people have tried to induce a period, such as having an orgasm, soaking in a warm bath, or taking vitamin C, these methods are considered ineffective and not scientifically proven.

The best remedy for delayed periods is to talk with a healthcare professional. They can help you figure out what’s causing your late periods and develop a treatment plan to help address the problem.

Antibiotics won’t delay your period, but that doesn’t mean your period won’t be late when you’re taking an antibiotic. Often, the stress of being sick is enough to cause a delay in your period.

If your period has been late, missed, or otherwise not normal lately, it’s a good idea to talk with a healthcare professional. They can help address any issue that might be causing your late period.