Many women report flu-like symptoms like headaches, muscle aches, nausea and vomiting as early pregnancy signs, though some typical flu symptoms like cough and fever are not related to pregnancy and may indicate illness instead. Here's how to tell the difference.
Early Signs of Pregnancy
Early signs of pregnancy will differ from woman to woman and even from pregnancy to pregnancy. While the most common sign of pregnancy is a missed menstrual period, women may also experience:
- Swollen, tender, enlarged or tingling breasts
- Darkening of the areolas
- Fatigue or lightheadedness
- Hunger, food cravings or aversions
- Nausea or vomiting
- Frequent urination
- Bloating, heartburn or constipation
- Mood swings
- Slight bleeding or spotting, which may be implantation bleeding
Timeline for Pregnancy Symptoms
Often, the first and most obvious sign of pregnancy is a missed period, though some women report breast changes, moodiness or fatigue before this first period is missed. If you have signs that could be caused by either the flu or pregnancy and suspect you are pregnant, using a home pregnancy test is a fairly reliable first step.
As the pregnancy progresses, you may have other symptoms that could be related to pregnancy or illness. For some women, morning sickness and heartburn gets worse and other symptoms may develop, including:
- Nasal congestion or headaches
- Back, hip or pelvic pain or leg cramps
- A general feeling of malaise or not feeling well
- Puffiness in the hands, face or ankles
- Nosebleed or bleeding gums
Pregnant women may experience even more discomfort in the second and third trimesters as their body adjusts to a growing baby. It's important to let your doctor know about all of the symptoms you are having, so any concerning ones can be assessed.
Some of the early pregnancy symptoms can mimic influenza, a contagious respiratory illness also known as the flu. According to the Centers for Disease Control and Prevention (CDC), signs and symptoms of the flu include:
- Muscle or body aches
- Tiredness or fatigue
- Runny or stuffy nose
- Sore throat
- Loss of appetite
- Vomiting and diarrhea (although this is a less common flu symptom in adults)
Flu symptoms, like signs of pregnancy, can be different from person to person and can vary in severity. While some symptoms — such as fatigue or nausea — may be related to either condition, pregnancy is not known to bring on fever, chills or cough.
Fever, Pregnancy and the Flu
During the menstrual cycle, the basal body temperature — the temperature of the body at rest — will increase. These subtle temperature changes can be tracked to help predict when ovulation is occurring, which can help provide the best timing for conception.
It's important to note, though, that neither ovulation nor conception will typically raise body temperature to fever levels. If you might be pregnant and your symptoms include a temperature of 100.4 degrees Fahrenheit or higher, contact your doctor because it's more likely the fever is being caused by an infection or illness than pregnancy.
How to Tell If You’re Pregnant or Sick
Many women anecdotally report flu-like symptoms as signs of early pregnancy, including
- Nasal congestion
Symptoms of a sore throat, fever and cough (with or without white, green or yellow mucus) are more likely due to a cold or flu than pregnancy. But if you're pregnant, these symptoms may be explained by a flu or cold that has coincided with your pregnancy.
Home Pregnancy Test
At-home pregnancy tests look for the presence of human chorionic gonadotropin, or hCG, in a woman's urine. This hormone is produced by the placenta and can usually be detected in a laboratory blood test several days before a missed period. Levels of hCG can vary woman to woman, especially in early pregnancy.
Home pregnancy tests vary in their sensitivity to detect hCG because they're measuring this substance in the urine. Some home tests might detect the hCG on the first day of a missed period, but these home tests are most accurate when the urine is checked one to two weeks after the menstrual cycle is missed.
When to See a Doctor
If you menstruate on a regular schedule and your period is a week late, it's a good idea to check to see if you're pregnant. Since medical check-ups and screening tests help keep you and your baby healthy throughout the pregnancy, be sure to set up a prenatal visit if your home test is positive for pregnancy.
Throughout your pregnancy, see your doctor if you have any of the following symptoms:
- Blurred vision or worsening eyesight
- Pain, burning or discomfort with urination
- Severe or persistent headaches
- Fever or chills
- Sudden or severe swelling in the hands, face or fingers
- Bleeding or leaking fluid from the vagina
- Cramping, pain or discomfort in the lower abdomen
- Vomiting or nausea and not able to eat or drink well
- Baby is moving less than usual after week 28
- Depressed, sad or have thoughts of harming yourself or your baby
What to Do If You’re Pregnant and Have the Flu
If you're pregnant and you have symptoms of the flu, call your doctor right away. The CDC recommends that anyone at high risk for flu complications, including pregnant women, receive prompt treatment — which may include antiviral medications.
So contact your doctor to report any flu symptoms and seek urgent medical care if you have difficulty breathing, shortness of breath, chest or abdominal pain or pressure, sudden dizziness, confusion or a high fever.
What Do YOU Think?
Have you ever been pregnant or had the flu? Or possibly both? How did you tell the difference? Was there a period of time when you were unsure? Share your thoughts, stories and questions in the comments below!
- Merck Manual: Detecting and Dating a Pregnancy
- Centers for Disease Control and Prevention: Flu Symptoms & Complications
- Merck Manual: Introduction to Symptoms During Pregnancy
- U.S. Department of Health and Human Services: What Are Some Common Signs of Pregnancy?
- Journal of the American Board of Family Medicine: Fertility Awareness-Based Methods: Another Option for Family Planning
- Merck Manual: Physiology of Pregnancy
- U.S. Food and Drug Administration: Home Use Tests: Pregnancy
- U.S. Department of Health and Human Services: Office on Women's Health: Pregnancy Complications
- Center for Disease Control and Prevention: Pregnant Women & Influenza (Flu)
- Merck Manual: Fever in Adults
- CBS News: The Best Pregnancy Test