Though symptoms of premenstrual syndrome (PMS) and pregnancy are often similar, there are several key differences and certain symptoms that are unique to each.


Premenstrual syndrome (PMS) is a group of symptoms linked to the menstrual cycle. Typically, PMS symptoms happen one to two weeks before your period. They usually stop after your period starts.

The symptoms of PMS can be very similar to those of early pregnancy. Read on to learn how to tell the difference. But remember, these differences are subtle and vary from woman to woman.

1. Breast pain

PMS: During PMS, breast swelling and tenderness can occur during the second half of your menstrual cycle. Tenderness ranges from mild to severe, and is usually the most severe right before your period. Women in their childbearing years tend to have more severe symptoms.

Breast tissue may feel bumpy and dense, especially in the outer areas. You may have a feeling of breast fullness with tenderness and a heavy, dull pain. The pain often improves during your period or right after, as your progesterone levels decrease.

Pregnancy: Your breasts during early pregnancy may feel sore, sensitive, or tender to the touch. They may also feel fuller and heavier. This tenderness and swelling will usually happen one to two weeks after you conceive, and it can last for a while as your progesterone levels rise due to your pregnancy.

2. Bleeding

PMS: You generally won’t have bleeding or spotting if it’s PMS. When you have your period, the flow is noticeably heavier and can last up to a week.

Pregnancy: For some, one of the first signs of pregnancy is light vaginal bleeding or spotting that’s usually pink or dark brown. This typically happens 10 to 14 days after conception and is usually not enough to fill pads or tampons. The spotting typically lasts for just a day or two, so it’s shorter than a normal period.

3. Mood changes

PMS: You may be irritable and feel a bit grouchy during PMS. You may also have crying spells and feel anxious. These symptoms typically go away after your period starts.

Getting some exercise and plenty of sleep may help take the edge off of your PMS moodiness. However, if you feel sad, overwhelmed, hopeless, or lack energy for two weeks or more, you could be depressed. Be sure to talk to your doctor.

Pregnancy: If you’re pregnant, you can have mood changes that last until you give birth. You’re more likely to be emotional during pregnancy. You may be ecstatic and excited, looking forward to the new member of your family. You may also have moments of sadness and cry more easily.

As with PMS, these latter symptoms can also indicate depression. If you’re concerned about your symptoms and think you might be depressed, be sure to talk to your doctor. Depression during pregnancy is common, and it can — and should — be treated.

4. Fatigue

PMS: Tiredness or fatigue is common during PMS, as is trouble sleeping. These symptoms should go away when your period starts. Getting some exercise can help improve your sleep and lessen your fatigue.

Pregnancy: While you’re pregnant, increased levels of the hormone progesterone can make you tired. Fatigue can be more pronounced during your first trimester, but it can last throughout your pregnancy as well. To help your body cope, be sure to eat well and get lots of sleep.

5. Nausea

PMS: You shouldn’t expect nausea or vomiting if your period is late but some digestive discomfort such as nausea can accompany symptoms of PMS.

Pregnancy: Morning sickness is one of the most classic and clear signs you’re pregnant. Bouts of nausea often begin a month after you get pregnant. Vomiting may or may not accompany the nausea. Despite the name, morning sickness can occur at any time of the day. However, not all women experience morning sickness.

6. Food cravings and aversions

PMS: When you have PMS, you’ll likely notice that your eating habits change. You may crave chocolate, carbohydrates, sugars, sweets, or salty foods. Or you may have a ravenous appetite. These cravings don’t happen to the same extent when you’re pregnant.

Pregnancy: You may have highly specific cravings, and you may be totally uninterested in other foods. You may also have an aversion to certain smells and tastes, even ones you once liked. These effects can last throughout pregnancy.

You could also have pica, in which you compulsively eat items that have no nutritional value, such as ice, dirt, dried paint flakes, or pieces of metal. If you have cravings for nonfood items, talk to your doctor right away.

7. Cramping

PMS: If you have PMS, you may experience dysmenorrhea, which are cramps that happen 24 to 48 hours before your period. The pain will probably decrease during your period and eventually go away by the end of your flow.

Menstrual cramps will often decrease after your first pregnancy or as you age. Some women will experience more cramping as they start to go into menopause.

Pregnancy: Early in pregnancy, you may experience mild or light cramping. These cramps will probably feel like the light cramps you get during your period, but they’ll be in your lower stomach or lower back.

If you have a history of pregnancy loss, don’t ignore these symptoms. Rest. If they don’t subside, talk to your doctor. You can have the cramps for weeks up to months when you’re pregnant. If you know you’re pregnant and these cramps are accompanied by any bleeding or watery discharge, see a doctor immediately.


It’s important to know the cause of your symptoms. If you’re pregnant, the sooner you find out, the sooner you can get the right care. The best way to tell the difference between symptoms of PMS and early pregnancy is to take a pregnancy test.

It can also be helpful to track your symptoms so you notice when there’s a change in your typical pattern. If you have questions or concerns about any of your symptoms, be sure to see your doctor.

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