One of the largest reports on COVID-19 vaccination in pregnancy bolsters evidence that it is safe although the authors say more comprehensive research is needed.

The preliminary results are based on reports from over 35,000 U.S. women who received either the Moderna or Pfizer shots while pregnant. Their rates of miscarriage, premature births and other complications were comparable to those observed in published reports on pregnant women before the pandemic.

The new evidence from researchers at the federal Centers for Disease Control and Prevention was published Wednesday in the New England Jou...