(NewsNation) — A new study found the COVID-19 vaccine may have prevented thousands of premature births.

The authors found that COVID-19 infection during pregnancy increased the risk of preterm birth, which can have lifelong consequences for infants. A fetus exposed to COVID-19 in the womb can also lead to health problems.

The study, published in the Proceedings of the National Academy of Sciences, found the increase of preterm births that happened during the COVID-19 pandemic dropped in 2022, likely as the result of vaccinations. Researchers also found that in places with early adoption of the vaccine, the level of preterm births dropped even earlier.

Researchers acknowledged some limitations, including the fact that infection during pregnancy varied because different populations had different levels of risk, based on factors including socioeconomic status. The fact that COVID-19 may be asymptomatic and testing requirements and documentation changed over time.

The COVID vaccine became available to all people over 16 in spring of 2021, but the rate of vaccination varied across different regions. Researchers noted by March of 2023, 70% of pregnant people had been vaccinated against COVID-19.

The authors used data from California, a large and diverse state, to determine if the vaccine impacted premature birth. They found by fall of 2022, a spike in premature births likely caused by COVID had disappeared.

Researchers concluded that by preventing premature births, the vaccine prevented long-term health complications for children as well as representing financial savings since preterm births can cost more than $80,000 per infant.

While researchers noted the findings show vaccination is critical for public health, they also cautioned the risk of infection for pregnant people and impact on premature birth may change as new variants of COVID-19 could be able to evade immunity granted by vaccines or prior infection.