COVID-19 may cause more preterm births, perinatal deaths in unvaccinated pregnant women
Women who have COVID-19 later in their pregnancy are more likely to have complications than women who get the disease earlier in their pregnancy or not have it at all, according to a study published in Nature Medicine.
Preterm births, stillbirths and newborn deaths were more common among women with the virus 28 days or earlier before their delivery date, the researchers said. Most complications occurred in unvaccinated women.
“Our data add to the evidence that vaccination in pregnancy does not increase the risk of complications in pregnancy, but COVID-19 does,” author Sarah Stock, MD, PhD, a reader in maternal and fetal health and an honorary consultant and subspecialist in maternal and fetal medicine at the University of Edinburgh Usher Institute, said in a press release.
“COVID-19 vaccination in pregnancy is crucial to protect women and babies from preventable, life-threatening complications of COVID-19,” said Stock, who is also a consultant obstetrician.
The researchers analyzed data from the COVID-19 in Pregnancy in Scotland database, including 87,694 women who were pregnant in Scotland from the time when COVID-19 vaccinations first were offered in December 2020 through October 2021.
While 77.4% of the general female population aged 18 to 44 years were fully vaccinated in October 2021, only 32.3% of women who gave birth in October 2021 were fully vaccinated.
Since Scotland began offering COVID-19 vaccines, there have been 4,950 cases of COVID-19 during pregnancy, with 77.4% (95% CI, 76.2-78.6) of these cases occurring in unvaccinated women, 11.5% (95% CI, 10.6-12.4) in partially vaccinated women and 11.1% (95% CI, 10.3-12) in fully vaccinated women.
The extended perinatal death rate among babies born within 28 days of their mother developing COVID-19 was 22.6 per 1,000 births (95% CI, 12.9-38.5). All deaths occurred among babies born to mothers who were unvaccinated against COVID-19 at the time of infection.
Also, 16.6% (95% CI, 13.7-19.8) of babies born within 28 days of their mother developing COVID-19 were delivered more than 3 weeks before their due date. The preterm birth rate among babies born to women with no confirmed SARS-CoV-2 infection during pregnancy was 7.9% (95% CI, 7.7-8.1).
The background perinatal mortality rate in Scotland during the study period was 5.6 deaths per 1,000 births (95% CI, 5.1-6.2), and the preterm birth rate was 8% (95% CI, 7.8-8.1). The researchers said it was not possible to say whether the virus contributed to these deaths or preterm births because they did not have access to detailed clinical records for individual women.
However, the perinatal mortality and preterm birth rates among women within 28 days of receiving a vaccine were similar to the background rates — 4.3 per 1,000 (95% CI, 2.9-6.4) and 8.2% (95% CI, 7-9.6), respectively.
The researchers also noted that 98% (95% CI, 92.5-99.7) of women with COVID-19 during pregnancy who were admitted to critical care were unvaccinated.
“Vaccine uptake has been much lower in pregnant women than in nonpregnant women of a similar age in Scotland,” author Aziz Sheikh, MSc, MD, director of the Usher Institute, said in the press release.
“As cases of omicron continue to rise, I strongly encourage all pregnant women to take up the offer of a vaccination or booster, as these will help protect them and their unborn child,” Sheikh said.