7 Common Pregnancy Infections and How to Prevent Them

Pregnancy infection prevention matters because an infection can affect your baby even when you feel fine. Some infections cause mild symptoms, or none at all, in the pregnant person, yet they can lead to pregnancy complications or illness in a newborn. That’s why prenatal screening and regular visits are so important, as explained in this healthy pregnancy checklist.

This guide covers seven common pregnancy infections: HIV, syphilis, hepatitis B, hepatitis C, chlamydia, gonorrhea, and group B strep. Prevention may include testing, safer sex, recommended vaccines before or after pregnancy, careful handwashing, food safety, and keeping every prenatal appointment. If you’re worried about symptoms or possible exposure, contact your prenatal provider instead of trying to diagnose the infection at home. Next, let’s look at each infection and the steps that can help protect you and your baby.

Watch a pregnancy guide to group B strep prevention

7 Common Pregnancy Infections and How to Prevent Them

These infections don’t all spread in the same way. Some pass through sexual contact or blood, while group B strep can live naturally in the body without causing illness. Because symptoms may be mild or absent, prenatal testing often catches risks that symptom tracking would miss. The CDC recommends routine screening for several infections during pregnancy, as outlined in its pregnancy infection screening guidance.

HIV: Early testing and treatment can protect both parent and baby

HIV can pass to a baby during pregnancy, birth, or breastfeeding. Without care, it can affect the baby’s health, but timely treatment greatly lowers the chance of transmission and supports the pregnant person’s health.

Every pregnant patient should receive an HIV test at the first prenatal visit. A provider may recommend repeat testing during the third trimester when exposure risk is higher. If the patient’s status is unknown during labor, rapid testing can help the birth team act quickly.

Condoms, partner testing, PrEP when appropriate, and avoiding shared needles can reduce exposure. A positive result is a medical finding, not a judgment. The prenatal care team can provide treatment, answer questions, and create a birth plan that protects both patients.

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Syphilis: Prenatal screening and partner treatment are key

Syphilis is a bacterial infection that can cross the placenta. Without treatment, it may cause miscarriage, stillbirth, premature birth, or congenital syphilis in the baby. Sores or rashes can be easy to miss, and some people have no noticeable symptoms.

Testing should happen at the first prenatal visit. Depending on personal risk, local infection rates, or clinical guidance, a provider may repeat testing later in pregnancy and at delivery. Treatment works best when it starts early.

Sexual partners need testing and treatment too. Otherwise, reinfection can occur after treatment. Contact a provider promptly after a new exposure, a possible sore, an unexplained rash, or another concern. The CDC’s pregnancy STI treatment guidance can help explain why follow-up matters.

Hepatitis B and hepatitis C: Blood screening helps plan newborn care

Hepatitis B and hepatitis C both affect the liver, but they are different viruses. They can spread through infected blood, shared needles, or other exposure routes. Hepatitis B can also spread through sex and during birth, while hepatitis C transmission during birth is less common but possible.

Every pregnancy should include hepatitis B surface antigen testing, called an HBsAg test, even after vaccination or a previous negative result. Finding hepatitis B before delivery allows the newborn to receive timely preventive care. CDC also recommends hepatitis C testing during each pregnancy so exposed infants can receive follow-up testing.

Protect yourself by avoiding shared needles, razors, toothbrushes, and other items that may carry blood. Use sterile equipment for injections, tattoos, and piercings. Asking new sexual partners about testing can also reduce risk. Hepatitis C has no vaccine, but hepatitis B vaccination may be recommended if you’re not protected.

Chlamydia and gonorrhea: Testing matters because symptoms may be absent

Chlamydia and gonorrhea can occur without noticeable symptoms. If untreated, either infection may cause pregnancy or newborn complications. Possible symptoms include unusual discharge, burning with urination, pelvic pain, or bleeding after sex, but symptoms are not a reliable screening method.

Pregnant patients younger than 25 should receive testing at the first prenatal visit. Patients 25 and older should also be tested when risk is higher, such as with a new partner, multiple partners, or a partner who has an STI. Repeat chlamydia testing in the third trimester may be needed when risk continues.

Condoms, mutual testing, and avoiding sex with untreated partners help prevent transmission. Take all prescribed treatment, and make sure partners complete treatment before having sex again.

Group B strep: A late-pregnancy swab guides birth care

Group B strep is a common bacterium that may live in the vagina or rectum without causing illness. It isn’t usually considered a sexually transmitted infection, and it isn’t caused by poor hygiene.

Screening commonly occurs around 35 to 37 weeks with a vaginal and rectal swab. A positive result usually means the birth team will give antibiotics during labor to lower the newborn’s risk of serious infection. Treatment focuses on labor rather than eliminating bacteria weeks earlier.

Tell your provider if you’ve previously tested positive or had a baby with group B strep disease. That history can change the plan for your next birth. You can also review these prenatal infection risks and prevention alongside your provider’s recommendations.

Everyday Pregnancy Infection Prevention Beyond STI Testing

STI screening is only one part of staying healthy during pregnancy. Daily habits also lower the risk of rubella, cytomegalovirus (CMV), foodborne illness, and urinary tract infections (UTIs). These are related prevention topics, not four additional infections in the main list.

Check vaccine protection before pregnancy, and plan postpartum vaccines

Rubella can cause serious fetal harm, especially during early pregnancy. Infection may lead to miscarriage, stillbirth, or congenital rubella syndrome, which can affect a baby’s hearing, eyesight, heart, and development.

The MMR vaccine protects against measles, mumps, and rubella. Because it is a live vaccine, providers don’t give it during pregnancy. When possible, check your vaccination records or rubella immunity before trying to conceive. If you receive an MMR shot, wait one month, or 28 days, before trying to become pregnant, following CDC pregnancy vaccine guidance.

If testing shows that you’re not immune during pregnancy, don’t panic. Your prenatal provider can plan vaccination after delivery, often before you leave the hospital. MMR can also be given while breastfeeding. Ask about hepatitis B vaccination and other recommended pregnancy vaccines too, since your needs depend on your health history, work, travel, and pregnancy.

If you accidentally receive MMR shortly before learning you’re pregnant, contact your provider, but this alone isn’t a reason to end the pregnancy.

Reduce CMV exposure through handwashing and safer childcare habits

Cytomegalovirus often spreads through saliva and urine from babies and young children. Many adults have no symptoms, yet CMV can affect a developing baby. Parents of toddlers, daycare workers, teachers, and healthcare workers may have more frequent exposure.

You don’t need to fear ordinary contact with children. Instead, focus on moments when body fluids may be present:

• Wash your hands with soap and water after diaper changes, feeding, wiping a child’s nose, or touching saliva or urine.
• Don’t share food, drinks, cups, utensils, toothbrushes, or pacifiers with young children.
• Avoid kissing young children on the mouth. A kiss on the forehead or cheek is a safer choice.
• Follow workplace safety rules when caring for children or patients, including hand hygiene and protective equipment when required.
• Use condoms if your partner may have CMV and you have concerns about sexual exposure.

If you work with young children, these habits can become part of your normal routine. Ask your prenatal provider about testing after a concerning exposure, especially if you develop symptoms or feel unsure about what happened.

Use food safety and urinary health habits every day

Pregnancy food safety starts with small kitchen choices. Wash your hands before preparing or eating food, rinse produce under running water, and keep raw meat, seafood, and eggs away from ready-to-eat foods. Cook meat and eggs thoroughly, refrigerate leftovers promptly, and follow guidance on higher-risk foods, including unpasteurized products and certain deli foods. Use these pregnancy food safety guidelines when planning meals.

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UTIs are also common during pregnancy and can worsen when untreated. Hygiene alone can’t prevent every UTI, so don’t ignore symptoms. Drink fluids, take regular bathroom breaks, and wipe from front to back. Staying hydrated while pregnant may support urinary health, but testing remains important.

Tell your provider about burning during urination, sudden urgency, fever, back pain, or blood in your urine. A urine test can identify an infection, and your provider can prescribe treatment that’s safe during pregnancy.

How Prenatal Visits Catch Infections Before They Become Urgent

Routine prenatal care gives your provider regular chances to find infections before symptoms appear or complications develop. A visit may include a conversation, blood or urine testing, and a review of your health history. These steps can feel ordinary, but they help your care team act while treatment and prevention options are still available.

For a broader look at what to expect at prenatal visits, remember that infection screening is only one part of your care. Your provider also checks your overall health, pregnancy progress, and any changes that need attention.

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What happens during the first prenatal screening

At the first prenatal visit, providers generally recommend testing for HIV, syphilis, hepatitis B, and hepatitis C. The CDC recommends early testing because a positive result can lead to treatment, newborn protection, or a delivery plan that lowers the chance of transmission. You can review the CDC pregnancy infection screening guidance if you want to understand the standard recommendations.

Chlamydia and gonorrhea screening depends on age and risk. Providers generally test pregnant patients younger than 25, along with older patients who have factors such as a new partner, multiple partners, a partner with an STI, or a recent infection. If risk continues, your provider may repeat testing later in pregnancy.

Your answers help shape these decisions. Share complete information about new partners, past infections, substance use, household exposures, travel, and missed appointments. Honest answers aren’t a confession or a judgment. They help your provider choose the right tests instead of relying on assumptions.

Why later pregnancy visits still matter

Some infections need repeat screening because exposure can happen after the first test. Depending on your risk, local rules, symptoms, or earlier results, your provider may repeat testing for syphilis, HIV, chlamydia, or gonorrhea during the third trimester.

Group B strep screening usually happens at 36 or 37 weeks with a swab. The result helps your birth team decide whether to give antibiotics during labor to reduce the newborn’s risk of serious illness. The CDC recommends this screening during every pregnancy, even when a cesarean birth is planned.

Timing can change with your age, medical history, local requirements, symptoms, or a new exposure. If you missed an appointment or a recommended testing window, don’t give up. Contact your provider, because testing can often happen later. Share what happened, ask what remains due, and make a new plan.

When to Call Your Prenatal Provider About a Possible Infection

Contact your prenatal provider when something feels unusual, even if the symptom seems mild. Infections can cause complications before they become obvious, and some cause no symptoms at all. Scheduled screening remains important because feeling well doesn’t rule out HIV, syphilis, hepatitis, chlamydia, gonorrhea, or other infections.

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Symptoms that deserve a prompt call

Call your prenatal provider soon if you develop:

• A fever of 100.4°F (38°C) or higher, chills, or a new rash.
• Painful sores, blisters, or ulcers around your mouth or genitals.
• Unusual vaginal discharge, a strong odor, itching, or irritation.
• Burning or pain during urination, pelvic pain, or back pain.
• Bleeding after sex or unexplained vaginal bleeding.
• A known STI exposure, possible HIV exposure, or sex with a partner who has an untreated infection.
• Contact with someone who has a contagious illness, especially if you develop symptoms afterward.

Your provider may recommend an exam, urine test, blood test, swab, or repeat screening. Share when the exposure happened and any symptoms you noticed. For more guidance, review these serious symptoms to report during pregnancy.

When to seek urgent medical care

Seek urgent care immediately for trouble breathing, confusion, severe abdominal or back pain, heavy bleeding, or fluid leaking from the vagina. Call right away if your baby moves less than usual, following your provider’s instructions for checking movement. The CDC’s urgent maternal warning signs can help you recognize symptoms that need immediate attention.

Don’t use leftover antibiotics or stop prescribed treatment early. Also, don’t assume an over-the-counter medicine, cream, or herbal product is safe during pregnancy. Ask your prenatal provider or pharmacist before taking anything, and follow the full treatment plan even when you start feeling better.

Conclusion

Preventing infections during pregnancy starts with steady prenatal care. Keep your appointments, complete recommended tests, practice safer sex, and make sure partners receive testing and treatment when needed. Wash your hands, handle food carefully, review your vaccine protection, and report symptoms or possible exposures early. These steps help your care team find concerns while there is still time to plan safe treatment and newborn care.

Infection screening is routine healthcare, not a sign that you’ve done anything wrong. Write down questions before your next visit, including concerns about symptoms, exposure, vaccines, or test results. A pregnancy week-by-week guide can also help you keep track of appointments and changes worth discussing.

Trust your instincts when something feels off. Early medical guidance gives families more options and helps protect both the pregnant person and baby.

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