The dreaded stomach bug seems to be passed between kids — and even babies — like Lego blocks. Adults can catch this virus too — especially those who are pregnant and therefore have a weakened immune system.

The stomach virus or stomach “flu” is also called gastroenteritis. Different kinds of viruses can cause this short-lived illness, whether you’re pregnant or not.

If you have the bug, try not to worry. Stomach viruses can cause lots of icky symptoms really quickly, but they’re usually pretty mild and go away on their own. It’s most likely that you and baby will be fine, even if you have a full-blown bout of the stomach flu.

However, sometimes very serious cases of the stomach virus during pregnancy can cause complications. Here’s what to watch for and when to see your doctor if you think you have a stomach bug.

It’s important to be aware of any symptom during pregnancy, including those of stomach viruses. This is because some symptoms might be the same as signs that you’re going into early labor.

If you have a stomach virus you might have symptoms such as:

  • fever
  • chills
  • nausea
  • vomiting
  • stomach cramping or pain
  • diarrhea
  • watery bowel movements
  • fatigue
  • headache
  • muscle aches
  • general pain or soreness

Common kinds of stomach viruses that you can catch during pregnancy (or other times) include:

Many stomach viruses are very contagious but end quickly. Symptoms can show up anywhere from 12 hours to 2 days after catching a virus. You’re contagious when you start showing symptoms.

You can catch a stomach virus by:

  • being in close contact with someone
  • eating contaminated food
  • eating raw or poorly cooked food
  • drinking contaminated water
  • using the same bathroom or changing a diaper when kids/babies in the home are sick
  • touching a contaminated surface or object
  • not washing your hands and touching your face or mouth

Although your body’s guard is down during pregnancy, it still has plenty of safeguards against bugs. Your baby is protected against stomach viruses and most other germs that manage to get in.

In fact, even if you’re violently ill with a stomach virus, the germs rarely get across the barrier (womb) around your baby. Even so, your illness can impact your baby’s well-being.

A stomach virus can leave you dehydrated and put your immune system into overdrive. These side effects can sometimes lead to serious pregnancy and birth complications.

The risks for your blossoming little one depend on where you are in your pregnancy.

The first trimester

You may not even be aware that you’re pregnant, but the first 12 weeks are very important. This is when your baby’s heart, brain, and other important parts all form, even though they’re still the size of a gummy bear.

Getting a stomach virus this early in the game can raise the risk of spine (neural tube) problems.

The second trimester

In the second trimester your baby is still developing and also rapidly growing. A serious stomach virus can sometimes cause development problems. If you’re not able to eat or drink enough, your symptoms may temporarily slow down your baby’s growth.

If you’re very ill with a stomach bug and losing lots of water, the amniotic fluid (your baby’s swimming pool) might also drain a little bit.

The third trimester

A stomach virus and other bugs like the flu virus can cause early or preterm labor in the third trimester. This means that your stomach cramps might lead to labor cramps a bit too early. This could happen if you’re so dehydrated that your baby isn’t getting enough water.

Dehydration can also lower amniotic fluid levels during this trimester. And in serious cases, you may not be able to make enough milk to feed your baby right after they’re born.

Most stomach viruses clear up in about 48 hours. If you have symptoms longer than this or if you can’t keep anything down, including water, let your doctor know.

Your doctor will first make sure you’re not dehydrated. This is can be harmful for you and for your baby. Next, you’ll probably need medical tests, like a physical checkup and blood tests to rule out other causes like:

An upset stomach from a bacterial infection can last longer than a stomach virus. It can also be more harmful during pregnancy for you and your baby.

Tell your doctor if you have stomach bug symptoms for longer than about 2 days. If you have a bacterial infection, like listeriosis, you’ll need antibiotic treatment.

Stomach viruses usually go away by themselves. You won’t need treatment, but home remedies can help ease symptoms.

  • Stay home. In addition to avoiding passing it to someone else, you’ll appreciate being near a bucket or a bathroom!
  • Get plenty of rest.
  • Drink plenty of fluids to replenish what you’re losing.
  • If you have a bit of an appetite, eat some carb-rich — but bland — foods (bread, pasta, potatoes, rice).
  • After your symptoms are gone, replenish your gut bacteria with probiotic-rich foods, like yogurt.

If you need pain relief for a headache and stomach cramps, ask your doctor about the best choice for you. Acetaminophen is typically safe during pregnancy. You can take up to two 500 milligram tablets four times a day.

Avoid over-the-counter treatments like antidiarrheal medications and anti-nausea drugs. They may not be recommended during pregnancy.

The truth about stomach viruses (whether you’re pregnant or not) is that they can cause water loss from — ahem — both ends. Not replacing this water right away can quickly lead to dehydration.

Your body needs even more water than normal when you’re pregnant. Keep yourself and your bun in the oven hydrated as you get over the stomach bug by:

  • drinking plenty of clear fluids like water, herbal tea, broth, and juice
  • drinking fizzy drinks like ginger ale
  • drinking sport drinks with added vitamins and minerals (but watch the sugar)
  • sucking on ice cubes or frozen juice bars
  • eating juicy fruit like an orange or watermelon
  • adding oral rehydration salts to drinks
  • avoiding caffeine (and always avoiding alcohol during pregnancy)

If you’re seriously dehydrated you might need to go to the hospital for treatment. A saline solution will be injected into your body with an IV to quickly hydrate you. Dehydration can trigger other complications in your body and put you at risk of other infections like a urinary tract infection — ouch.

If you have the stomach flu, check for signs that you might be dehydrated:

  • dark yellow urine
  • not urinating much
  • feeling thirsy
  • dizziness
  • fainting
  • irritability
  • fast heart rate
  • fast breathing
  • feeling tired or sleepy
  • confusion

Stomach bugs are common, and just about everyone catches one eventually. But you’re more likely to get a stomach virus if you’re pregnant. You might feel really unwell, but your body knows how to protect your growing baby.

Stomach viruses rarely affect your baby directly. However, how sick you are can make a difference. See your doctor if you have any new symptoms during your pregnancy.