If you are planning pregnancy, review your vaccination record before you start trying. MMR and varicella are live vaccines and are not given during pregnancy; CDC advises avoiding pregnancy for about one month after these vaccines. Other vaccines, including seasonal influenza, may be given before or during pregnancy when indicated. COVID-19 guidance now uses individual decision-making, with greater benefit for people at higher risk, including pregnancy.
Your vaccine plan depends on timing
Why vaccines are a preconception issue
Some infections are especially dangerous during pregnancy, but some of the vaccines that prevent them cannot be given once you are pregnant. That makes the months before conception the easiest time to close gaps.
Rubella is the classic example. Infection during pregnancy can cause congenital rubella syndrome. The MMR vaccine prevents rubella, but because MMR is a live attenuated vaccine, CDC recommends giving it before pregnancy rather than during pregnancy.
MMR: check immunity before you need it
If you are not immune to rubella or are not up to date on MMR, CDC recommends vaccination before pregnancy and avoiding pregnancy for at least four weeks afterward.
Most adults were vaccinated in childhood, but records disappear and immigration, school history, age, and prior vaccine schedules can complicate the picture. Your clinician can help determine whether documentation or immunity testing is appropriate.
Varicella: the other live vaccine to think about early
Varicella vaccine is also contraindicated during pregnancy. CDC advises nonpregnant people who receive it to avoid pregnancy for one month after each injection.
If you are already pregnant and discover you are not immune, the usual plan is to avoid exposure and vaccinate after pregnancy rather than receive the live vaccine during pregnancy.
Flu, Tdap, RSV, and COVID are different conversations
| Vaccine | Pregnancy timing in current CDC guidance |
|---|---|
| Influenza shot | Recommended seasonally; can be given before or during pregnancy. |
| Tdap | Recommended during each pregnancy, preferably during weeks 27–36. |
| RSV (Abrysvo) | Used during a specific late-pregnancy window and season when indicated. |
| COVID-19 | 2025–2026 recommendations use individual decision-making; pregnancy increases risk for severe COVID-19. |
The exact schedule can change over time, which is why “I read a vaccine list three years ago” is not enough. Use the current CDC schedule and your clinician’s advice.
What if you got a live vaccine and then found out you were pregnant?
Do not panic. CDC explicitly notes that inadvertent varicella vaccination during or shortly before pregnancy is not itself considered a reason to terminate a pregnancy.
Contact your prenatal clinician and provide the vaccine name and date so they can give exposure-specific guidance.
- Find your vaccination record if possible.
- Ask whether you have documented MMR and varicella immunity.
- Review seasonal and risk-based vaccines.
- If a live vaccine is needed, ask exactly how long to wait before trying.
- Do not delay a needed pregnancy vaccine because an old internet list said “no vaccines while pregnant.”
Frequently asked questions
How long should I wait after MMR before trying to conceive?
CDC advises avoiding pregnancy for at least four weeks after MMR vaccination.
Can I get a flu shot while TTC?
Yes. Inactivated influenza vaccine can be given before or during pregnancy when seasonally recommended.
Is every vaccine unsafe in pregnancy?
No. Some are specifically recommended during pregnancy, while live vaccines such as MMR and varicella are contraindicated.
Sources & guidance
- CDC: Vaccines before, during and after pregnancy
- CDC: Vaccinating pregnant women
- CDC: COVID-19 vaccination in pregnancy (2025–2026)