Does an Abnormal Period Mean Pregnancy?

The Menstrual Cycle
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You know your period. You know when to expect it. You know how to calculate the number of pads or tampons you will need. You probably even know what you can get away with wearing in terms of clothes based on your flow. So you would know if your period were unusual in any way.

A menstrual cycle, or period that is unusual or different in some way than your typical, normal period could mean a lot of different things.

This may mean that your period lasts longer or is shorter or that it comes earlier or later than anticipated. It may be a difference in the amount of flow. You would know this form a decreased number of tampons or pads used or a flow that was not as heavy as anticipated or that was heavier than you thought it should be. It could even end early. You may also find that it stops and starts, even if it overall, lasted the same number of days. Basically anything that isn't what you would expect is abnormal and should be watched.

What causes an abnormal period?

There are a number of things that cause your period to be abnormal. These can include things like:

  • stress
  • increased or decreased exercise
  • change in sleep patterns
  • medications
  • illness
  • pregnancy

Any variances in your period may indicate that you are pregnant. Typically this is what you may think of first when you think of your period being off or missing.

Though it certainly is a possibility, it may not be the most likely scenario for you based on your use of birth control and sex life. An example of this might be a woman who is taking oral contraceptives, the pill, and has an unusual period. She takes her birth control pills regularly and has not missed any days, nor had a medication change that would alter her birth control status.

If her period is lighter or shorter, it is more likely simply a result of less build up in her endometrium (uterine lining), than pregnancy. Certainly pregnancy could be an option, but it doesn't make it the most likely option.

What if you are pregnant and had a period?

How do women confuse their periods with pregnancy? One thing we have learned as women from a very small age is that pregnancy means you won't have a period. So any disruption in our period means pregnancy in our minds. This happens in a couple of ways.

Sometimes the bleeding you have isn't your period. This could be that you've thought of bleeding as a period, when it was really implantation bleeding. This is bleeding that occurs around the time the fertilized egg is burrowing into your endometrium. This may look like spotting and confuse someone into thinking they had a really light period, until they miss their second period.

You may also be having bleeding because you are pregnant and something is going on. This might be a hormonal issue, or impending miscarriage that requires you to get care from a doctor or midwife. 

What if your period is abnormal?

The best thing to do is to take a pregnancy test if you think your period was weird.

If it's negative, wait for your next period. If it is also weird, consider seeing your doctor or midwife for an exam to help get to the bottom of the weirdness.


Obstetrics: Normal and Problem Pregnancies. Gabbe, S, Niebyl, J, Simpson, JL. Sixth Edition.

Ovulation Calendar. March of Dimes. Last Accessed Februrary 9, 2016.

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