COVID-19 does affect pregnancy, and the risks are meaningful. Pregnant people with COVID-19 are roughly 40% more likely to develop serious complications or die compared to uninfected pregnant people, based on a large study published in JAMA. The virus raises the stakes for both mother and baby, increasing the chances of conditions like preeclampsia, stillbirth, and preterm delivery. The good news: vaccination is safe during pregnancy, and antiviral treatments are available.
Why Pregnancy Increases COVID-19 Severity
Pregnancy reshapes your immune system and puts extra demand on your heart and lungs. These normal changes make it harder for your body to fight off respiratory infections, and COVID-19 is no exception. Compared to uninfected pregnant patients, those diagnosed with COVID-19 are significantly more likely to need mechanical ventilation, develop blood clots, or experience heart muscle disease. Postpartum hemorrhage and other infections also occur at higher rates.
The timing of infection matters. Third-trimester infections carry the highest risk. In one study, average hospital stays for third-trimester infections were about 10 days, compared to 4 days for first-trimester infections and 6 days for second-trimester infections. Maternal deaths were concentrated almost entirely in the third trimester, with 24.2% of third-trimester patients dying in that cohort versus no deaths among first-trimester patients. Fetal outcomes follow a similar pattern: babies did best when mothers were infected in the first trimester (92.9% had good outcomes) and worst in the third trimester (66.7%).
Preeclampsia Risk Doubles
Preeclampsia is a dangerous blood pressure condition that can develop during pregnancy, and COVID-19 roughly doubles the odds of getting it. In a study of over 1,500 unvaccinated women, those with a COVID-19 infection had an adjusted odds ratio of 2.1 for developing preeclampsia compared to uninfected women. This association held up even after researchers controlled for factors like age, number of pregnancies, and prenatal care visits. The link was specific to preeclampsia without pre-existing high blood pressure.
Preeclampsia can restrict blood flow to the placenta, raise the risk of seizures, and force early delivery. Since COVID-19 already triggers widespread inflammation and blood clotting problems, it likely amplifies the vascular stress that leads to preeclampsia in the first place.
Stillbirth and Placental Damage
The stillbirth risk is one of the most sobering findings. A CDC analysis of over 1.2 million deliveries between March 2020 and September 2021 found that COVID-19 nearly doubled the risk of stillbirth overall. The stillbirth rate was 1.26% among deliveries with COVID-19 versus 0.64% among those without. During the Delta variant period, that gap widened dramatically: 2.70% of COVID-affected deliveries resulted in stillbirth, compared to 0.63% of unaffected deliveries.
The mechanism appears to center on the placenta. COVID-19 can cause placentitis, an inflammation of the placenta that leads to blood clots and fibrin deposits within the tissue. This damage restricts oxygen and nutrient delivery to the fetus, driving intrauterine growth restriction. Research in animal models has confirmed that placental inflammation, rather than direct fetal infection, is the key driver of these complications.
Can the Virus Pass to the Baby?
Vertical transmission, where the virus passes from mother to fetus during pregnancy or delivery, is possible but uncommon. A systematic review of multiple studies found that over 70% of neonatal infections were likely picked up from environmental exposure after birth rather than in the womb. About 20% of cases were attributed to potential vertical transmission, most often during the third trimester.
Delivery method doesn’t eliminate the risk. Several reports noted that most infected newborns were delivered by cesarean section, suggesting that viral transfer can happen before labor begins, possibly through the placenta or amniotic fluid. Researchers are still working to pin down the exact routes, but the overall rate remains low relative to the number of infected pregnancies.
Neurodevelopmental Effects on Children
A growing body of evidence suggests that in utero COVID-19 exposure may have lasting effects on child development. A large retrospective study tracking over 18,000 births found that children born to mothers infected with SARS-CoV-2 during pregnancy were 29% more likely to receive a neurodevelopmental diagnosis by age 3, after adjusting for factors like maternal age, socioeconomic status, preterm birth, and vaccination status.
Among exposed children, 16.3% received a neurodevelopmental diagnosis by 36 months, compared to 9.7% of unexposed children. The most common diagnoses were speech and language disorders, developmental motor disorders, and autism spectrum disorder. Autism diagnoses specifically occurred in 2.7% of exposed children versus 1.1% of unexposed children. The effects were strongest when infection occurred in the third trimester (36% increased risk) and in male offspring (43% increased risk for third-trimester exposure). Female offspring showed a more modest, statistically insignificant increase.
These findings don’t mean that COVID-19 infection during pregnancy will cause developmental problems in your child. Most exposed children developed normally. But the association is strong enough to warrant attention and follow-up with your child’s pediatrician if you notice speech delays or developmental concerns.
Vaccination Is Safe During Pregnancy
A meta-analysis pooling data from 21 studies and nearly 150,000 women found that COVID-19 vaccination does not increase the risk of miscarriage. The miscarriage rate among vaccinated women was 9%, consistent with the known background rate before the pandemic. Compared to unvaccinated women, vaccinated women had virtually identical rates of ongoing pregnancy and live birth.
Both ACOG and the CDC recommend that pregnant people receive COVID-19 vaccines. Vaccination during pregnancy also provides a secondary benefit: antibodies pass to the baby through the placenta during pregnancy and through breast milk after delivery. Studies confirm that vaccinated breastfeeding mothers have measurable antibodies in their breast milk, which may offer some protection to newborns who are too young to be vaccinated themselves.
Treatment Options If You Get Infected
If you test positive for COVID-19 during pregnancy, antiviral treatment is available and recommended. ACOG and the CDC advise against withholding treatment simply because someone is pregnant. The preferred outpatient antiviral can be started as soon as you test positive or are highly suspected positive based on symptoms and known exposure, and it involves a five-day course of tablets taken twice daily.
Treatment is particularly important if you have underlying heart or lung disease, are immunosuppressed, or are unvaccinated. Despite clear guidelines, antiviral medications have been underutilized in pregnant patients compared to non-pregnant patients. If you test positive and your provider doesn’t mention treatment, it’s worth asking about it directly.
Breastfeeding After COVID-19
Breastfeeding is encouraged even if you’ve had COVID-19. The virus has not been shown to transmit reliably through breast milk, and the antibodies present in milk after infection or vaccination may actually help protect your baby. If you’re actively sick, standard precautions like hand washing and wearing a mask while feeding can reduce the chance of spreading the virus through respiratory droplets.