The American congress of obstetrics and gynecologists(ACOG) has issued a recent
practice advisory for influenza vaccination during pregnancy.
A recent case -control study published in September issue of journal Vaccines
linked spontaneous abortion and receipt of influenza vaccine in first trimester
of pregnancy. In this case control study women had nearly twice the odds of
experiencing a miscarriage if they were vaccinated in the preceding 28 days
period. (OR 2.0; 95% CI 1.1–3.6)
The odds of spontaneous miscarriage were further increased 7 times if the
women also received the pH1N1-containing vaccine in the previous influenza
season. (OR 7.7; 95% CI 2.2–27.3)
Once the 28 days window is passed, not increased chances of spontaneous pregnancy
loss was observed.
The same study also observed no adverse effects or pregnancy loss when
vaccination was given either later in the first trimester or in the second or
third trimester.
Hence, ACOG reviewed the evidence by evaluating all the scientific
information available and concluded that this study had some limitations and does
not establishes causality. It also calls for additional studies and clinical trials
before the concern is fully addressed.
ACOG still affirms it stand of vaccinating every pregnant woman with a
flu shot, irrespective of the trimester she is in.
For many years, ACOG and the CDC have recommended that every pregnant
woman receive a flu shot during any trimester.
