How Can You Tell if You're Pregnant if You Have Irregular Periods?

Medically Reviewed on 4/11/2022

What is pregnancy and irregular periods?

You can tell if you're pregnant even if you have irregular periods with signs of pregnancy other than a missed period, such as implantation bleeding, nausea, swollen or tender breasts, fatigue, frequent urination, mood swings, headaches, backaches, and changes in cravings or aversions.
You can tell if you're pregnant even if you have irregular periods with signs of pregnancy other than a missed period, such as implantation bleeding, nausea, swollen or tender breasts, fatigue, frequent urination, mood swings, headaches, backaches, and changes in cravings or aversions.

Irregular periods can make it difficult to know whether you’re pregnant. It can make it harder to predict ovulation (when a mature egg is released from the ovary) or determine the best date to take a pregnancy test. Depending on the cause, women with irregular periods may also have greater difficulty getting pregnant.

Most women have menstrual cycles that are about 28 days long, give or take a few days on either end. Their cycles may change from month to month but will usually stay within that range.

An irregular menstrual cycle may be less than 24 days or greater than 38 days. Bleeding that lasts longer than eight days is also abnormal.

If you are concerned about irregular periods and pregnancy, there are signs of pregnancy other than a missed period and additional ways to determine when you are most likely to get accurate results with a pregnancy test.

Signs of pregnancy with irregular periods

If you are pregnant, you may experience any or all of the following symptoms of early pregnancy:

Implantation bleeding

Some women bleed at the time of implantation, which occurs about one or two weeks after fertilization. It can be easy to mistake the signs of implantation, which include cramps and bleeding, for a light period. Some things that can help you tell the difference are:

  • Unlike some periods, implantation bleeding never includes clots of coagulated, or semisolid, blood and tissue.
  • Implantation bleeding is very light in flow.
  • While period blood is reddish, implantation bleeding is pink or brown.
  • Implantation bleeding should only last one to three days.


Due to hormonal changes, nausea is one of the most common symptoms of early pregnancy, often starting as early as two weeks after conception. It may or may not be accompanied by vomiting. Low blood sugar levels in the morning often react with the hormones, leading to more frequent nausea in the morning.

Swollen or tender breasts

Some women first notice the effects of pregnancy hormones on their breasts, which can become swollen or tender.


During early pregnancy, your body is changing to accommodate the fetus, which can make you feel tired. Rising levels of progesterone (a hormone that regulates the menstrual cycle) can also contribute to fatigue.

Other symptoms

The following symptoms are less common in the first few weeks of pregnancy but may still occur during the first trimester:

Causes of pregnancy with irregular periods

Many women have irregular periods at some point between adolescence and menopause (when a woman’s period stops). Periods are often irregular during adolescence and during perimenopause (when your body makes the natural transition to menopause).

Other causes of irregular periods include:

When to see the doctor for pregnancy with irregular periods

You might see the doctor for irregular periods in any of the following cases:

  • Your period suddenly becomes irregular after being regular
  • You haven’t had a period for 90 days or more
  • You have a period more often than every 21 days or less often than every 35 days
  • Your period lasts for more than seven days
  • Your period is unusually heavy
  • Your period is incredibly painful
  • You bleed in between your periods

Your doctor will help determine the cause of your irregular period and suggest a course of action.


The first sign of pregnancy is most often: See Answer

Diagnosis for pregnancy with irregular periods

There are many causes of irregular periods, including pregnancy. While home pregnancy tests claim to be most accurate after a missed period, it can be difficult to know when you have missed a period if you’re irregular.

If you think you may be pregnant, try waiting either 28 days since you last had sex or 36 days from your last period. Take the test again a few days later if it is negative but you still think you may be pregnant.

In order to diagnose your irregular periods, your doctor may perform any of the following examinations or tests:

Your doctor will also take a detailed family and personal history to help them evaluate the results.

Treatments for pregnancy with irregular periods

The treatments for irregular periods vary based on the diagnosis and may involve treatment for an underlying disorder. The following types of irregular periods require different treatments:

The treatment for absent, infrequent, or irregular periods may include:

The treatment for heavy or prolonged periods may include:

The treatment for painful periods may include:

  • Nonsteroidal anti-inflammatory medications
  • Contraceptives
  • The application of a heating pad

Talk to your doctor about what treatment for irregular periods might be right for you.

What are the chances of getting pregnant on your period?

>Whether or not you’re trying to conceive, you might have some questions surrounding pregnancy. One common question that teens and women ask is whether they can become pregnant while on their period.

The average menstrual cycle — the changes in the uterus and ovaries that make pregnancy possible — typically lasts 28-30 days.

Your cycle begins the day you start bleeding. About halfway through your cycle, usually around days 12-14, ovulation occurs. This is when an egg is released from your ovaries into your fallopian tubes, where they can be fertilized by a man’s sperm.

It’s at this time, during ovulation, when a woman is most fertile and most likely to get pregnant if she is having sex. If you have a typical 28-day menstrual cycle and you ovulate around day 14, you are most likely to get pregnant in the days right before and after the egg is released. However, this is not the only time you can get pregnant.

Signs and symptoms of ovulation

It’s possible that you can get pregnant outside of the fertility window, or the days of your cycle when you are most likely to get pregnant. The best way to know when this period will occur is by tracking your menstrual cycle.

Tracking your cycle

To calculate your cycle, track it for three to four months to determine the average length. Count the days from the start of one period to the start of the next. Again, the average is around 28 days, but this varies. If your average cycle is between 21 and 35 days, you can split this number in half to determine when your fertility window will most likely occur.

Vaginal discharge

Another way to know if you are ovulating is to monitor your vaginal discharge. During your most fertile days, your vaginal discharge becomes stretchy and thick. Experts compare it to an uncooked egg white.

It’s worth noting that this method only works for women who are not using hormonal birth control. Women who take birth control pills do not ovulate, so they do not have a change in vaginal discharge.

Causes of pregnancy while on your period

Knowing when you’re ovulating can help you get or avoid getting pregnant. However, there are some factors that may throw off your calculations regarding ovulation.

Vaginal bleeding

Some women experience vaginal bleeding during ovulation, which can be mistaken for menstruation. The chances of getting pregnant during your actual period are much lower because ovulation is a couple of weeks away, but it’s not impossible. A woman may mistake spotting from ovulation as her period, which could cause pregnancy if a form of birth control isn’t used during sex.

Early ovulation

It’s possible that you may ovulate early. Factors like stress, weight gain or loss, and hormonal changes can affect your cycle and when you ovulate, even if you have a fairly normal cycle. If you ovulate early and do not use protection, your chances of getting pregnant increase.

Sperm can live in your body up to seven days after you have sex. If you ovulate early, even when you think it’s the safest, it’s still possible that you can get pregnant. So, even though chances are the lowest of getting pregnant during your period, it’s not impossible.

Diagnosis/tests for pregnancy

If you think you are pregnant, you can take an at-home pregnancy test about two weeks after the date you believe conception took place. Home tests are quite accurate and are 97%-99% reliable.

If you have a positive at-home test, you should make an appointment with your doctor. Your health care provider will test either your urine or blood for pregnancy. Your doctor will also give you a physical exam to help determine whether you are pregnant.

If you have a negative at-home test but you still believe there’s a chance you might be pregnant, you should also make an appointment with your doctor to find out for sure.

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Medically Reviewed on 4/11/2022
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