Title: Maternal and perinatal outcomes of pandemic influenza in pregnancy
Funder: Department of Health and Social Care

Abstract: Design: National cohort study using the UK Obstetric Surveillance System (UKOSS). Setting: All consultant-led hospital maternity units. Target population: Pregnant women. Health technologies being assessed: Pandemic influenza. Measurement of costs and outcomes: The following outcomes will be compared between women with influenza and comparison women, and explored in different subgroups according to management variations: maternal death, maternal level 3 critical care unit admission, other major maternal complication, preterm birth, congenital anomaly, perinatal death. Sample size: The primary objective of this study is to determine the incidence of pandemic influenza infection in pregnancy. The study size will therefore be dependent on the infection rate among pregnant women, together with the UK maternity rate (currently approximately 800,000 maternities per year). If the patterns are similar to the previous pandemic, we anticipate identifying 3-500 affected pregnancies during a 6 month initial study period. Information on up to 1500 comparison women is available from existing UKOSS data. A study of this size will have 80% power at the 5% level to detect a doubling of the risk of any adverse outcome (severe maternal morbidity or mortality, preterm delivery, congenital malformation or perinatal death) in women with influenza compared with comparison women. Project timetable: PRE-ACTIVATION PHASE (provisional start date 1 June 2012) January 2012 Apply for necessary approvals, develop web-based reporting systems, finalise and format data collection form and clinician information. ACTIVATION PHASE Week 1: Study information mailed/emailed to clinicians Week 3: Data collection commenced Months 2-6: Ongoing reporting of new cases, data analysis, production of management guidance and dissemination. Months 7-10: Collection of remaining pregnancy outcome data Month 12: Final pregnancy outcome analysis, production of guidance and dissemination

Lay abstract: This study will collect anonymous information about all pregnant women admitted to hospital during a pandemic with confirmed influenza. The study will document the number of pregnant women admitted to hospital with confirmed influenza and will describe what happens to these women and their babies. By comparing the information with women who have not had influenza, and between groups of women who are given different treatments, the study will generate information to inform guidance for doctors, midwives and policy makers. By analysing the information each month during a pandemic, the research team, working together with the groups making guidance, aim to inform changes to guidance as the pandemic develops to improve outcomes for women and their babies. The main ethical issue arising from this study is that we plan to collect information about women without their explicit consent. We will therefore collect anonymous information only; no names, addresses, postcodes, hospital or NHS numbers will be collected so that the researchers will not be able to identify any women from their information. The information will be collected after the woman has been diagnosed with influenza; the management of individual women will not in any way be changes by inclusion of their data in the study. This planned process is as recommended by the National Information Governance Board. The research team has the necessary expertise to carry out this comprehensive national study, including public health, birth defects, statistics, guideline development and obstetrics. The National Perinatal Epidemiology Unit (NPEU) has a national and international reputation for conducting studies which change policy, influence practice and improve the care of women and their babies, and reports regularly to the Department of Health. The UKOSS was set up at the unit and has been led successfully by the lead applicant since 2005. She also led a similar successful study during the 2009 pandemic. One of the co-applicants is the Royal College of Obstetricians and Gynaecologists lead for pandemic influenza planning and will provide a direct link to produce ongoing updated guidance through the RCOG pandemic influenza planning group.

Research activity codes: 4.4 POPULATION SCREENING
Health categories: INFECTION