Seasonal influenza A (H1N1) infection in early pregnancy and second trimester fetal demise

DOI: 10.3201/eid1701.091895
Suggested citation for this article: Lieberman RW, Bagdasarian N, Thomas D, Van De Ven C. Seasonal influenza A (H1N1) infection in early pregnancy and second trimester fetal demise. Emerg Infect Dis. 2011 Jan; [Epub ahead of print]

Seasonal Influenza A (H1N1) Infection in Early Pregnancy and Second Trimester Fetal Demise
Richard W. Lieberman, Natasha Bagdasarian, Dafydd Thomas, and Cosmas Van De Ven
Author affiliation: University of Michigan Health System, Ann Arbor, Michigan, USA

A second trimester fetal demise followed influenza-like illness in early pregnancy. Influenza A virus (H1N1) was identified in maternal and fetal tissue, confirming transplacental passage. These findings suggested a causal relationship between early exposure and fetal demise. Management of future influenza outbreaks should include evaluation of products of conception associated with fetal loss.

Increased maternal illness and death appeared in early reports of influenza A pandemic (H1N1) 2009. Three pregnancy-related complications associated with pandemic (H1N1) 2009 were reported in May 2009: 1 postpartum maternal death, 1 preterm birth, and 1 early second trimester (weeks 14–20) loss (1). In April 2010, a summary of pandemic (H1N1) 2009 among 788 pregnant women demonstrated a disproportionately high risk for death; the rate of spontaneous miscarriage was 1.4%, but details were not provided (2). Correlating influenza exposure to pregnancy loss is not straightforward because first trimester miscarriage is common, second trimester loss before 24 weeks is not well studied (3), and viral identification in products of conception has rarely been attempted. We report a second trimester fetal demise that occurred after exposure to seasonal influenza A virus (H1N1) early in pregnancy.

full-text:
http://www.cdc.gov/eid/content/17/1/pdfs/09-1895.pdf