Pregnant women who are unvaccinated against the coronavirus are not only more likely to be hospitalized if they contract covid-19, but are at more risk of seeing their newborns die less than a month after birth, according to a peer-reviewed study in Scotland that was published Thursday.
The study was released in Nature Medicine, a monthly journal. The authors looked at more than 144,000 pregnancy records going back to March 2020, when the first coronavirus case was detected in Scotland.
But the authors focused on data between December 2020 and October 2021 because that was when vaccine shots and tests were more widely available. During that period, the unvaccinated made up 77% of all pregnant women who were infected and more than 90% who required hospitalization and critical care.
All of the infant deaths examined in the study occurred in mothers who had not been vaccinated at the time of their covid-19 diagnoses, the authors said. The results add urgency to vaccination efforts to protect parents and babies during the remainder of the pandemic they said.
"Our findings emphasize the need for continued efforts to increase vaccination uptake in pregnant women. ... Vaccine hesitancy in pregnancy thus requires addressing," the authors wrote.
Pregnant women initially received inconsistent advice about whether and when to get vaccinated, in part because they were not included in initial vaccine trials. In April, health officials in the United Kingdom and the United States began to actively encourage vaccination during pregnancy.
The risk of stillbirth or neonatal death -- defined as the death of a baby less than a month old -- appeared to be highest among women who delivered within four weeks of the onset of infection, the study states. The risks were more than four times higher than those for babies born among the general population.
The study found that vaccine coverage was lower among pregnant women than for women in the general Scottish population, as has also been documented in the United States. For instance, less than one-third of women who gave birth in October had had two vaccine doses, when more than three-quarters of women in the general population had gotten two doses.
The Scottish study echoes what the U.S. Centers for Disease Control and Prevention published earlier this month and comes as misinformation about vaccination during pregnancy has been spreading widely.
The CDC conducted a retrospective study on more than 40,000 pregnant women and concluded that vaccination during pregnancy was not associated with increased risk for preterm births -- defined as before completing 37 weeks of pregnancy -- or with giving birth to "small-for-gestational-age" babies.