Nov. 7, 2025 — Moms-to-be know it’s important to avoid illness during pregnancy. Two new studies offer fresh insights on protecting your baby’s development, especially as experts predict a late-winter rise in COVID.
Here’s what to know if you’re pregnant or planning to be this winter.
First-trimester COVID vaccination is again shown to be safe: An analysis of more than half a million births in France showed that there was no increased risk of 75 major birth defects among mothers who got an mRNA-based COVID-19 vaccine during the first trimester. The findings were published Oct. 15 in the journal JAMA Network Open.
- Why first trimester protection matters: Some of the most sensitive development happens during the first trimester — every major organ and body system is forming, including the brain, plus the umbilical cord reaches full capability to move oxygen and blood to the embryo by eight weeks. University of Minnesota maternal fetal medicine specialist Devika Maulik, MD, said patients often ask her if it’s OK to get the COVID vaccine during the first trimester — an understandable concern, she noted, given the widespread vaccine misinformation online. “What this study is showing is that you don't have to wait,” she said, adding that previous large studies have reached the same conclusion.
- The bottom line: COVID poses serious risks to pregnancy, including higher rates of stillbirth and preterm birth, so having vaccine protection throughout all trimesters is important. And previous studies show there is no increased risk of miscarriage following mRNA vaccination.
COVID during pregnancy may increase your baby’s risk of a neurodevelopmental diagnosis: A new study shows that babies in Massachusetts whose moms had COVID during pregnancy in 2020 or 2021 had a 29% increase in the odds of being diagnosed with a developmental disorder by age 3. These included autism spectrum disorder, motor disorders (affecting balance, involuntary movements like tics, or conditions such as cerebral palsy that impact muscle tone and coordination), and speech delays. As in other studies, COVID infection during pregnancy was also linked to higher rates of preterm birth and lower birth weight, the researchers reported Oct. 30 in the journal Obstetrics and Gynecology. They examined health data for 18,124 babies born from March 2020 through May 2021, among whom 861 had mothers who had COVID during pregnancy. Most of the moms were infected during the third trimester.
- How common were developmental disorders? Among moms who had COVID during pregnancy, 16.3% of babies were diagnosed with at least one of more than a dozen disorders, compared to 9.7% of babies born to moms who didn’t get COVID during pregnancy.
- How common was an autism diagnosis? Autism diagnosis occurred among 2.7% of babies born to moms with COVID, compared to 1.1% of babies born to non-COVID moms. In contrast, speech and language disorders affected 9.5% of those born to moms with COVID and 4.7% of those born to non-COVID moms.
- The bottom line: Maulik reminds her patients that autism and neurodevelopmental studies consistently point to a mix of genetics and environmental factors, not a single cause. So this latest study “is not saying that COVID causes autism if you're exposed in the third trimester,” but it does suggest that COVID during pregnancy could affect your child’s neurodevelopment, she said.
So when during pregnancy should you get the COVID shot? The new studies highlighted different trimesters. It’s safe to get the vaccine in the first trimester, and the risk of neurodevelopmental disorders was highest when moms got COVID during the third trimester.
- Doctors say: The American College of Obstetricians and Gynecologists recommends getting the COVID vaccine at any point during pregnancy — the earlier, the better. Maulik agrees, noting that early vaccination helps protect the entire pregnancy. Getting it sooner won’t reduce the benefit of passing protective antibodies to your baby after birth, she added.
- The bottom line: Maulik said COVID “seems to impact the architecture of the placenta,” which is why she advises patients to avoid anything that can cause widespread inflammation, including infections. “COVID triggers a pretty massive amount of inflammation in the body that sometimes the body does not completely recover from,” she explained.
“I tell my patients, try to take care of yourself the best you can — and part of that is preventing viral infections,” she said. “If there’s a vaccine available, it not only benefits you during pregnancy but also your baby,” by reducing inflammation and passing on protective antibodies that can help lessen inflammation if the baby gets sick after birth.
