The American College of Obstetricians and Gynecologists (ACOG) continues to recommend that all pregnant women receive the influenza vaccine regardless of the trimester of pregnancy.

ACOG president Haywood L. Brown, MD, released a statement on the organizations position in light of a recent study (Donahue, et al. Vaccine) which associated spontaneous abortion to influenza vaccination during early pregnancy. In the study, the increased risk of pregnancy loss occurred within the first 28 days post-vaccination.

“Scientifically, it is unclear why this would occur,” stated Dr. Brown. “In the same study, when vaccination was given either later in the first trimester or in the second or third trimester, there was no association seen with pregnancy loss or any other adverse pregnancy outcomes.” 

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The association was found only among women who received a pH1N1-containing vaccine during the previous flu season and the authors stressed that their findings did not establish a causal relationship.

ACOG monitors vaccine safety to provide accurate recommendations to Ob-Gyns. In evaluating the study the organization believes there to be “insufficient information to support changing the current recommendation.” Both Dr. Brown and the authors of the study stated the need for further studies to address the concerns raised.

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