RSV during pregnancy

By trimester

Weeks 1–13

1st trimester

The fetal picture is reassuring: RSV is not expected to increase the chance of birth defects. What deserves attention is fever, which is worth reporting on its own in early pregnancy regardless of the cause.

Weeks 14–27

2nd trimester

A middle-of-pregnancy RSV infection is usually just an unpleasant cold that outstays its welcome. Symptoms that shift downward into the chest, or that worsen after day five or six, are the ones to flag.

Weeks 28–birth

3rd trimester

Breathing room is already limited by the third trimester, so chest symptoms feel worse and need a lower threshold for a call. This is also the window when the maternal RSV vaccine conversation happens, at 32 to 36 weeks.

What does the evidence show for RSV?

• RSV is a common respiratory virus that usually causes mild, cold-like symptoms, with babies, older adults, and people with weakened immune systems facing the higher chance of severe illness including pneumonia. 1
• It is not known whether pregnant women have a higher chance of developing severe RSV symptoms, and pre-existing lung conditions are the factor most often named as raising personal risk. 1
• RSV in pregnancy is not well studied, but it is not expected to increase the chance of birth defects, and preterm delivery or low birth weight were not common among the cases reviewed. 1
• In a surveillance cohort of pregnant women with confirmed RSV, cough and congestion each appeared in 7 of 8 cases and sore throat in 6 of 8, while fever showed up in only 3 of 8, and every woman with lower respiratory symptoms was at least 6 days from symptom onset. 2
• Breastfeeding is encouraged even while you have RSV, since breast milk from someone with the infection might carry protective antibodies that lower the chance the baby gets sick. 1

When should I call my provider about RSV?

Cough and congestion that shift into shortness of breath, wheezing, or chest tightness deserve prompt attention: in a study of pregnant women with confirmed RSV, those lower-respiratory symptoms only showed up six days or more after illness onset, not right away. Fever with RSV was also concentrated in the group with more severe symptoms, often paired with chest pain, loss of appetite, and reduced activity. Consult your healthcare provider the same day for new breathing trouble, a fever, or uterine contractions, and for symptoms that are getting worse rather than better after the first week. Trust your read on your own body. If something feels off beyond the list above, please consult your healthcare provider rather than waiting it out.