Abstract
Background/Aims It is known that seasonal influenza infection disproportionately impacts pregnancy. Based on preliminary information, the pandemic H1N1 virus that first surfaced in spring 2009 appears to cause disproportionate morbidity and mortality among pregnant women - possibly to an even greater degree than that seen from seasonal flu. While it is estimated that over 10% of the pandemic influenza-related deaths in the United States have been in pregnant women-there is little data on the total impact of H1N1 infection upon pregnant women and their developing infants. This study will present a population-based assessment of the impact of H1N1 flu upon pregnancy, maternal, and birth outcomes.
Methods This is an open cohort study covering the seasonal (mid 2008–2009) and H1N1 (mid 2009–2010) influenza seasons, with follow-up for pregnancy and infant outcomes up to one month after delivery. All pregnant women in KPNC, KPSC, KPCO, KPMA and KPGA during this period (mid 2008–2010) will be categorized according to their infection status as defined via lab test and/ or ICD-9 code for influenza-like-illness. Descriptive and regression analyses will be conducted to examine neonatal and pregnancy outcomes.
Results Due to time constraints in relation to availability of the most recent data within Kaiser Permanente, the final data extraction will not be completed until November 2010. Statistical analyses will be conducted on the following outcomes:: pregnancy (pre-eclampsia, eclampsia, premature labor, premature delivery, pregnancy-induced hypertension; maternal (hospitalization for respiratory-related conditions, other hospitalizations, death); infant (intra-uterine growth retardation; low birth weight, major congenital anomalies); vaccine use and effect (extent to which pregnant women received H1N1 and seasonal flu vaccine; impact of vaccination upon the risk for adverse pregnancy, maternal and infant outcomes); antiviral use and effect (extent to which pregnant women received antiviral medication for H1N1 or seasonal flu, and the impact of these therapeutics upon the risk for adverse pregnancy, maternal and infant outcomes).
Conclusions This study will be both analytic and descriptive, showcase the abilities of CESR and inform the scientific and public health communities with a range of unique information related to H1N1 infection during pregnancy within the combined KP populations.Note: Final analyses and results will be presented at the HMORN Conference.
