RSV during pregnancy carries real risks for both the mother and the baby. Pregnant women with RSV are nearly twice as likely to experience severe complications at delivery compared to those without the infection, and the virus is linked to higher rates of preterm birth. Most healthy pregnant women recover without serious problems, but pregnancy creates specific vulnerabilities that make RSV more concerning than it would be otherwise.
Why Pregnancy Makes RSV Riskier
Your body undergoes significant changes during pregnancy that make respiratory infections harder to fight off. As the uterus grows, it pushes the diaphragm upward and reduces lung capacity, leaving less room for your lungs to expand fully. At the same time, your immune system shifts to tolerate the genetically distinct fetus growing inside you. The part of your immune system responsible for attacking viruses is dialed down, while the part that builds long-term immune memory is enhanced. This trade-off is necessary for a healthy pregnancy, but it means viral infections like RSV can take hold more easily and linger longer.
These changes don’t make every RSV case dangerous. Many pregnant women experience it as a bad cold: congestion, cough, mild fever, fatigue. But for some, the combination of reduced lung capacity and suppressed antiviral defenses allows the infection to progress into the lower respiratory tract, where it becomes a more serious problem.
Complications for the Mother
A large study published in AJOG Global Reports found that pregnant women hospitalized with RSV at the time of delivery had a severe complication rate of about 50 per 1,000, compared to 17 per 1,000 in women without RSV. After adjusting for other health factors, RSV infection was associated with an 82% increased risk of severe maternal complications.
The most concerning complications were respiratory in nature. Acute respiratory distress syndrome, a condition where the lungs fill with fluid and struggle to deliver oxygen to the blood, occurred at roughly seven times the rate seen in uninfected women. Sepsis, a dangerous bodywide response to infection, was about five times more common. Women with RSV were also far more likely to have prolonged hospital stays of seven days or more (88 per 1,000 vs. 16 per 1,000).
These numbers reflect women who were sick enough to still have active RSV at delivery, so they represent the more severe end of the spectrum. A mild RSV infection earlier in pregnancy that resolves on its own is a different situation. Still, the data makes clear that RSV is not trivial during pregnancy, particularly in the third trimester when lung capacity is already at its lowest.
Risks to the Baby
RSV infection during pregnancy is associated with an increased risk of preterm delivery. Babies born early face their own set of challenges, including underdeveloped lungs and longer stays in the neonatal intensive care unit. The research suggests that the respiratory stress RSV places on the mother’s body may trigger early labor, though the exact mechanism is still being studied.
RSV does not appear to cross the placenta and directly infect the fetus the way some viruses can. The danger to the baby is indirect: it comes from the mother’s illness triggering preterm birth, or from the baby being exposed to RSV shortly after delivery if the mother is still contagious. Newborns who catch RSV in their first weeks of life are especially vulnerable because their airways are tiny and their immune systems are immature.
Treatment During Pregnancy
There is no antiviral medication for RSV. Treatment is supportive, meaning it focuses on managing symptoms while your body clears the virus. For mild to moderate cases, that means rest, plenty of fluids, and over-the-counter fever or pain relief. Most infections resolve within one to two weeks.
If symptoms worsen, particularly if you develop difficulty breathing, persistent high fever, or signs of dehydration, hospital care may be needed. In severe cases, supplemental oxygen or other respiratory support can help while your body fights the infection. The key is not to dismiss worsening respiratory symptoms as a normal part of being pregnant. Shortness of breath is common in late pregnancy, but sudden difficulty breathing or a feeling that you can’t get enough air warrants prompt medical attention.
RSV Vaccination During Pregnancy
A maternal RSV vaccine (Pfizer’s Abrysvo) is now available and recommended by the CDC. The vaccine is given as a single dose between weeks 32 and 36 of pregnancy, during the months of September through January in most of the continental United States. This timing aligns with RSV season and ensures the baby is protected during the months when the virus circulates most heavily.
The vaccine works by prompting your body to produce antibodies against RSV, which then cross the placenta and provide passive immunity to your baby. It takes about two weeks after vaccination for protective antibodies to develop and transfer. This is why the vaccine is not recommended after 36 weeks and 6 days: there simply isn’t enough time for antibodies to build up, cross the placenta, and reach protective levels before delivery.
The protection passed to your baby lasts approximately six months after birth, covering the window when infants are most vulnerable to severe RSV illness. Only Abrysvo is approved for use in pregnancy. Two other RSV vaccines on the market (GSK’s Arexvy and Moderna’s mResvia) are not approved for pregnant women.
Protecting Yourself During Pregnancy
RSV spreads through respiratory droplets and contaminated surfaces, much like a cold. The same precautions that reduce your risk of other respiratory infections apply here: frequent handwashing, avoiding close contact with people who are visibly sick, and keeping your hands away from your face. RSV can survive on hard surfaces like doorknobs and countertops for several hours, so wiping down shared surfaces during RSV season (typically fall through early spring) is a practical step.
If you have older children in daycare or school, your exposure risk goes up significantly, since RSV circulates widely among young kids. You can’t isolate yourself entirely, but being aware of the risk and taking basic hygiene precautions can reduce the chance of infection during the most vulnerable weeks of your pregnancy.