Major study confirms COVID-19 vaccination does not affect fertility
Extensive population data from Sweden supports the safety of COVID-19 vaccines for women of childbearing age.
- 10 February 2026
- 4 min read
- by Linda Geddes
At a glance
- During the COVID-19 pandemic, some people raised questions about the safety of COVID-19 vaccines during pregnancy, prompting researchers to look at large-scale health data to provide clear, evidence-based answers.
- A new study, published in the journal Communications Medicine, examined health records for nearly 60,000 women in Sweden. It found that childbirth and miscarriage rates were the same regardless of women’s vaccination status.
- The findings add to a growing number of studies from around the world showing that COVID-19 vaccination does not affect the chances of becoming pregnant or having a baby.
A large Swedish population study has found no evidence that COVID-19 vaccination affects a woman’s chances of having a child.
Researchers from Linköping University in Sweden analysed health registry data from nearly 60,000 women and found that childbirth and miscarriage rates were the same regardless of vaccination status.
The findings, published in Communications Medicine, add to growing international evidence supporting the safety of COVID-19 vaccines for people of childbearing age.
Why did these researchers study COVID-19 vaccination and fertility?
During the pandemic, scientists became aware of online rumours about COVID-19 vaccines and fertility that were spreading faster than clear medical evidence.
Early claims seeded concerns that mRNA-based COVID-19 vaccines might affect the placenta or make it harder to become pregnant, although follow-up research found no biological basis for this.
At the same time, falling birth rates in several countries led some to wonder if the timing was connected to vaccination campaigns, although in this case too, studies of pregnancy and newborn health have already provided reassuring results.
By studying tens of thousands of women, the researchers hoped to provide further evidence for the safety of COVID-19 vaccination in pregnancy, and for those who are thinking about starting a family.
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Dennis Nordvall at Linköping University and colleagues analysed medical records for nearly 60,000 women aged 18 to 45 living in Jönköping County, a region that closely reflects Sweden’s population as a whole. About three-quarters of these women received at least one COVID-19 vaccine dose during the study period.
The team linked vaccination records with data on childbirths, miscarriages and deaths, allowing them to compare pregnancy outcomes between vaccinated and unvaccinated women over time. Importantly, they accounted for age, since the likelihood of having a baby naturally varies across a woman’s reproductive years.
They also estimated when each pregnancy likely began and examined whether vaccination occurred before or after that point, helping to ensure the timing didn’t distort the results.
What did the study find about vaccination and pregnancy outcomes?
The researchers observed that the number of births in Jönköping County fell by about 8% from 2021 to 2022, followed by smaller declines over the next two years.
However, they found no meaningful difference in pregnancy outcomes between women who were vaccinated against COVID-19 and those who were not.
The findings add to a growing number of studies from around the world showing that COVID-19 vaccination does not affect the chances of becoming pregnant or having a baby, and may even be associated with fewer birth complications.
Childbirth rates were the same in both groups once factors such as age were taken into account. This is in line with several previous studies that have not found any association between COVID-19 vaccination and fertility.
Miscarriage rates were also similar, with no statistical evidence that vaccination increased pregnancy loss.
“Our conclusion is that it’s highly unlikely that the mRNA vaccine against COVID-19 was behind the decrease in childbirth during the pandemic,” said Prof Toomas Timpka at Linköping University, the study’s senior author.
The findings add to a growing number of studies from around the world showing that COVID-19 vaccination does not affect the chances of becoming pregnant or having a baby, and may even be associated with fewer birth complications.
Recent research has also suggested that babies born to women who were vaccinated against COVID-19 during pregnancy are protected against symptomatic infection for at least six months.
If not vaccination, what explains the drop in birth rates?
The researchers say the drop in births during the pandemic is more convincingly explained by social and demographic factors than by vaccination. Many people postponed big life decisions, including starting or growing a family, amid economic uncertainty, health worries and the upheaval to everyday life.
Longer-term population trends may also play a role: today’s prospective parents were born in the 1990s, when birth rates in Sweden were lower, so there are simply fewer people now at typical childbearing ages.
Taken together, these broader forces provide a more likely explanation for falling birth numbers than COVID-19 vaccination.
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