Study adds evidence that COVID-19 vaccination during pregnancy 'safe and beneficial'

Receiving a COVID-19 vaccine while pregnant did not increase the risk for peripartum outcomes and may lower the infant’s risk for NICU admission and intrauterine fetal death, according to a systematic review and meta-analysis.

Previous research has shown that COVID-19 vaccines are safe and provide benefits at any time during pregnancy for both mothers and newborns. Boosters, too, are well-tolerated during pregnancy and lactation. Still, Atsuyuki Watanabe, MD, of the division of hospital medicine at the University of Tsukuba Hospital in Japan, and colleagues wrote that COVID-19 vaccination rates remain low in pregnant people.

“Increasing vaccination rates in pregnant individuals are of paramount importance because they are at high risk for maternal morbidity and adverse perinatal outcomes,” they wrote. “However, many pregnant individuals hesitate to receive COVID-19 vaccination despite global vaccination campaigns.”

To further confirm the safety and efficacy of COVID-19 vaccines in pregnant people, Watanabe and colleagues conducted a systematic review and meta-analysis of nine studies that included 255,346 pregnant people who did not receive COVID-19 vaccination and 81,349 who did. Among the vaccinated participants, 98.2% received a messenger RNA vaccine.

The researchers found that, regardless of the timing of the first dose, COVID-19 vaccination was not connected to an increased risk for adverse outcomes in mothers or infants. In fact, mothers who were vaccinated during pregnancy faced a lower risk for being infected by the SARS-CoV-2 virus (OR = 0.46; 95% CI, 0.22-0.93). In addition, COVID-19 vaccination was not associated with an increased risk for postpartum hemorrhage (OR = 0.95; 95% CI, 0.83-1.07) or a cesarean delivery (OR = 1.05; 95% CI, 0.93-1.2).

When it came to the infants, COVID-19 vaccination during pregnancy was associated with a lower risk for intrauterine fetal death (OR = 0.73; 95% CI, 0.57-0.94) and NICU admission (OR = 0.88; 95% CI, 0.8-0.97).

“This positive association between COVID-19 vaccination during pregnancy and neonatal outcomes is plausible because SARS-CoV-2 infection in pregnant individuals may be associated with higher risks of NICU admission, [intrauterine fetal death] and perinatal mortality,” Watanabe and colleagues wrote.

In terms of timing, when mothers received COVID-19 vaccination during the second or third trimester, they had significantly lower risks for preterm birth (OR = 0.8; 95% CI, 0.69-0.92) and small for gestational age (OR = 0.94; 95%, CI 0.88-1) compared with unvaccinated mothers. The researchers found no significant difference in the risk for preterm birth between pregnant individuals who received the first vaccination during the first trimester vs. those who were not vaccinated. However, they noted that the number of individuals who were vaccinated during the first trimester was low, so this result “should be interpreted with caution.”

“Our findings are reassuring and encouraging for pregnant individuals to consider COVID-19 vaccination,” the researchers wrote. “Although vaccinated and unvaccinated populations were not precisely matched, our findings should be widely disseminated to address the disparity and vaccine hesitancy.”

Watanabe and colleagues also wrote that “maternal protection against SARS-CoV-2 is paramount” because, in previous studies, most pregnant people who required intensive care for COVID-19 were unvaccinated, and COVID-19 severity “appeared to be related to worse maternal and neonatal outcomes.”

“Moreover, it should also be noted that even asymptomatic SARS-CoV-2 infection was associated with higher risks of maternal outcomes, including preeclampsia and preterm labor,” the researchers wrote. “Given the promising efficacy of COVID-19 vaccination in preventing maternal SARS-CoV-2 infection and the critical association between COVID-19 and neonatal/maternal outcomes, our findings further underlined the importance of maternal protection against SARS-CoV-2 infection.”

Further, they wrote that the meta-analysis “will serve a critical role when counseling pregnant patients regarding the COVID-19 vaccination’s teratogenicity.

“Our findings suggest that COVID-19 vaccination during pregnancy is safe and beneficial to mothers and newborns.