Premenstrual syndrome (PMS) causes several symptoms that resemble early pregnancy, such as cramping and tenderness. However, it is possible to differentiate between PMS and pregnancy symptoms.

Symptoms of both premenstrual syndrome (PMS) and pregnancy can vary from person to person, but they often include tenderness in the breasts, cramping, and changes in mood.

This article compares the symptoms of PMS with those of early pregnancy. It also explores the differences between the two.

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The following symptoms can occur with both PMS and pregnancy.

Changes in mood

Changes in mood are common in both early pregnancy and the days leading up to a period. These can include crying spells and feeling irritable, anxious, or sad.

These symptoms of PMS typically occur before menstruation begins. However, if mood changes persist and a person misses their period, this may suggest pregnancy.

About 1 in 5 people worldwide experience a mental health condition during pregnancy.


Research suggests that constipation affects up to 38% of people during pregnancy, but it can also affect a person just before their periods.

Constipation is more likely to occur in the first two trimesters. A person with PMS-related bowel problems may experience relief after their periods begin.

Learn more about constipation in pregnancy.

Breast pain and tenderness

Breast changes are a common symptom of both PMS and early pregnancy. The changes can include:

  • pain
  • tenderness
  • swelling
  • heaviness
  • sensitivity
  • bumpy breast tissue

The severity of these symptoms varies among individuals.

However, in people with PMS, breast-related symptoms are usually most significant just before a menstrual period, and they typically get better during the period or just after it ends.

In early pregnancy, the breasts may feel particularly tender to the touch, and they often get heavier. The area around the nipple may sting or feel sore. Some women also develop more noticeable blue veins near the surface of the breasts.

Breast symptoms during pregnancy begin 1–2 weeks after conception and may persist until childbirth.


The hormone progesterone contributes to tiredness and fatigue before a period. Fatigue may go away once the period begins.

For a person with heavy periods, excessive tiredness can last throughout the period. It may also be a sign of iron-deficiency anemia.

Fatigue is also a common symptom of early pregnancy. It often persists throughout the first trimester, and some people feel tired for the full pregnancy. Resting whenever possible can help a person manage fatigue or tiredness.

Learn more about period fatigue.

Bleeding or spotting

Light spotting or bleeding can occur in early pregnancy. This is called implantation bleeding, and it typically occurs 1–2 weeks after fertilization.

Not everybody will experience implantation bleeding. Others may not notice it. It is much lighter than menstruation.

PMS does not typically cause spotting, although a period can be very light on the first day. Usually, menstrual bleeding lasts for 4–5 days, and it causes more significant blood loss than the spotting of implantation.


Cramping is common in both PMS and early pregnancy. Early pregnancy cramps can be similar to menstrual cramps, but they may persist for longer.

These cramps may persist during pregnancy, as the embryo implants and the uterus stretches.

Learn about cramps without periods.

Headaches and back pain

Hormonal changes can cause both headaches and back pain in early pregnancy and before the menstrual period.

Changes in appetite

Increased appetite and food cravings are common symptoms of pregnancy, but they can also occur with PMS.

Many people with PMS experience increased appetite and cravings for sweet or fatty foods, or carbohydrate-rich meals. Changes in the hormones estrogen and progesterone likely influence cravings just before a period.

Research indicates that 50–90% of pregnant people in the United States have cravings for specific foods.

Many crave specific foods and have aversions to others, finding their sight or smell deeply unpleasant. Food aversions are much less common in people with PMS.

Some pregnant people crave non-food items, such as ice or dirt. The medical term for this phenomenon is pica. Anyone with pica should contact a doctor.

Some symptoms are more likely to indicate early pregnancy than PMS. However, a person can only be sure by taking a home pregnancy test or visiting a doctor.

A missed period

Missing a period is one of the most obvious signs of pregnancy. If a period is late and pregnancy is a possibility, take a pregnancy test. Some pregnancy tests can detect pregnancy earlier than others.

However, there can be many other reasons for a missed or late period, such as:

  • stress
  • low body weight
  • polycystic ovary syndrome (PCOS)
  • going on or off birth control, or switching methods
  • having a medical condition such as thyroid disease or diabetes
  • menopause

Learn more about what can cause a missed period and negative pregnancy test.


While mild digestive discomfort can occur just before a menstrual period, nausea and vomiting are not typical PMS symptoms.

They are, however, common symptoms of early pregnancy. Nausea affects up to 80% of pregnant people. Nausea and vomiting usually start before the 9th week of pregnancy.

Typically, these symptoms subside by the second trimester, but some people experience nausea throughout pregnancy.

Nipple changes

Although breast changes can occur during both PMS and pregnancy, changes to the nipples rarely happen before a period.

If the areola, the colored area around the nipple, gets darker or larger, this can suggest pregnancy.

Learn more about breast changes during pregnancy.

Anybody who suspects that they are pregnant can take a home pregnancy test. If the result is positive, make an appointment with a doctor to confirm the pregnancy and plan the next steps.

If the test is negative, but a person misses three periods in a row, it is also a good idea to contact a doctor.

The doctor can help determine the reason for a late or missed period and recommend treatment options. They can also address concerns about any unusual symptoms.

Here are some frequently asked questions about pregnancy and PMS.

How can you tell if you are pregnant before your period?

Some symptoms, such as nausea, are more likely to occur with pregnancy than PMS. However, taking a pregnancy test is the only way to accurately determine if a person is pregnant.

How early do pregnancy signs start?

A missed period is usually the first sign of pregnancy. Symptoms of morning sickness, such as nausea and vomiting, typically begin after around 4–6 weeks. However, symptoms can be different for each person.

Many symptoms can occur with both pregnancy and PMS. These include mood changes, constipation, breast pain and tenderness, fatigue, bleeding, cramping, headaches, and appetite changes.

However, some symptoms are more likely to indicate pregnancy. These include nausea, nipple changes, and missing a period.

A home pregnancy test can help determine if a person is pregnant. They should contact their doctor if they are pregnant or if they have concerns about missed periods.