How Can You Tell the Difference Between Stomach Flu and Morning Sickness?

Updated March 18, 2019
Feeling sick during pregnancy

When you feel sick to your stomach, you may be unsure if you have the stomach flu or a case of morning sickness (nausea and vomiting during pregnancy). If you've been wondering, "am I sick or pregnant?" look for the symptoms that can help you tell the difference between them.

Common Symptoms of Morning Sickness and Flu

Morning sickness and stomach flu (viral gastroenteritis) have similar symptoms. The American College of Obstetrics and Gynecology (ACOG) points out that typical symptoms of morning sickness include stomach queasiness, nausea, and vomiting. These symptoms are normal, and according to ACOG, usually do not harm the fetus. But they can affect your ability to function normally throughout the day.

Since some of the symptoms of early pregnancy are similar to symptoms of being ill (such as a flu bug), it can be difficult to tell the difference. Morning sickness is not always confined to the morning. Instead, like a stomach bug, you can have symptoms throughout the day.

In both morning sickness and the flu, nausea, vomiting, or diarrhea, can range from mild to severe and lead to:

  • Dehydration
  • Loss of electrolytes
  • Weakness
  • Lightheadedness
  • Dizziness
  • Fatigue

ACOG suggests that you discuss symptoms with your healthcare provider if they are causing you concern or interfering with your life. In some cases, a condition called hyperemesis gravidarum may be to blame. Hyperemesis gravidarum is a term used by medical professionals for a severe form of morning sickness that occurs in about 3% of pregnancies.

Symptoms of Morning Sickness vs. Stomach Bug

Does early pregnancy feel like a stomach bug? It can, especially if you are experiencing other symptoms. Because the symptoms are similar, it might not be easy for you to tell the difference.

One way to tell to determine if you have morning sickness or a stomach bug is the duration of symptoms. According to the Centers for Disease Control and Prevention (CDC), symptoms of the stomach flu will improve within a few days while morning sickness usually persists until the second trimester of pregnancy. If you have the stomach flu and happen to be pregnant, you will continue to have morning sickness after diarrhea and systemic symptoms of the stomach flu subside.

You can also compare symptoms other than nausea and vomiting. There are some symptoms that are unique to morning sickness and some that indicate the flu.

Woman holding her stomach

Morning Sickness Symptoms

Additional early pregnancy symptoms other than nausea and vomiting of morning sickness include:

  • Breast tenderness and swelling
  • Cramping
  • Spotting or light bleeding
  • Sensitivity to smells
  • Headache
  • Backache
  • Fatigue
  • Darker nipples/areola
  • Prominent veins in breasts
  • Bloating
  • Mood swings
  • Missed period
  • Frequent urination
  • Food cravings
  • Food aversions

If you are experiencing these symptoms or any combination of these symptoms in addition to nausea and vomiting, there may be a chance you're pregnant.

Stomach Flu Symptoms

Additional symptoms of the stomach flu other than nausea and vomiting include:

  • Diarrhea
  • Stomach or intestinal cramping
  • Low-grade fever
  • Headache
  • Joint stiffness
  • Muscle aches
  • Fatigue

Symptoms from the stomach flu can be mild to severe and will develop within 24 to 72 hours after being exposed to the virus. Symptoms typically last a couple days but could persist for up to 10 days.

Of course, you could be pregnant and have the stomach flu at the same time. If you suspect that you might be pregnant, do a home pregnancy test or see your doctor for one to confirm. Don't take any herbal or other over-the-counter medicines to treat your symptoms until you are certain you are not pregnant.

Other Causes of Nausea and Vomiting

There are a number of possible causes for nausea and vomiting other than morning sickness and stomach flu which include:

How to Manage Morning Sickness or Stomach Bug

There is no medicine that can cure the stomach flu, which is caused by a virus, or morning sickness, whose cause is uncertain. Over-the-counter (OTC) anti-diarrhea and prescription anti-nausea medicines can only alleviate the symptoms until each condition passes. Also, it is important to note that how you respond to medicine cannot help you tell the difference between stomach flu and morning sickness.

At-Home Treatments

Certain at-home treatments may be able to alleviate the symptoms of morning sickness. ACOG suggests that changing your meal timing and changing the types of food that you eat might help you to manage morning sickness symptoms. They also suggest that taking certain vitamins can help to reduce symptoms. For instance, some studies suggest that taking a vitamin B6 supplement may be helpful in reducing nausea and vomiting.

The following at-home remedies will help you manage both stomach flu and morning sickness:

  • Drink enough fluids, including electrolyte solutions such as Gatorade, to replace what you lose from vomiting or diarrhea.

  • Ginger tea or ginger chews are recommended for morning sickness and may also help you relieve the nausea of stomach flu.
  • Eat small meals of bland, non-spicy foods such as foods on the BRAT diet.

Medical Intervention

Consult your doctor if you have symptoms of morning sickness or stomach flu and any of the following:

  • Moderate to severe symptoms
  • Can't eat or drink enough
  • Feel weak and listless
  • Feel lightheaded or dizzy
  • Loss of weight
  • You are only passing small amounts of urine and it is dark
  • A fever of a 101 degrees Fahrenheit or greater
  • Symptoms prevent you from doing your usual activities

Severe or prolonged vomiting or diarrhea that leads to weight loss, dehydration, and loss of electrolytes may need to be treated by your doctor, especially if you are pregnant.


Nausea and vomiting can be attributed to various conditions and diseases. If you find yourself experiencing these symptoms, prioritize your needs and reach out for care when you need it. You and your doctor may need to do a little investigative work in order to come up with a conclusive diagnosis so you can be treated accordingly or you can begin your prenatal care for your pregnancy.

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How Can You Tell the Difference Between Stomach Flu and Morning Sickness?