Midwifery managers of the maternity sites distributed questionnaires to all midwives working in their line of management.
Denominator populations for Australia and New Zealand were estimated using the number of births in participating maternity sites between January 1 2010-December 31 2011.
This cross-sectional study was conducted at 19 maternity sites across the seven health regions of country Western Australia.
A potential limitation of the study was the incremental participation of maternity sites in AMOSS over the course of the study which may have impacted recruitment of cases.
Following approval from the Executive Director of Nursing and Midwifery Services WACHS, we contacted midwifery managers of 19 maternity sites in the seven health regions of country Western Australia (WA) (Kimberley, Pilbara, Midwest, Goldfields, Wheatbelt, South West and Great Southern).
The Executive Director of Midwifery and Nursing Services sent an email to Regional Nurse Directors, Coordinators and Directors of Nursing, and midwifery managers employed in WACHS maternity sites requesting them to encourage all midwives to complete the questionnaire.
Rates were calculated using denominators estimated from data provided by participating maternity sites on women giving birth (defined as the birth of one or more live or stillborn infants of at least 400 g birthweight, or at least 20 weeks' gestation) in Australia and New Zealand.
We hypothesized that yearly differences in death rates result from changes in the timing of infection as P. destructans becomes established and that the environment serves as a source of infection for bats (bats that leave summer maternity sites are not infected; 7 ).
Over the corresponding period in Australia and New Zealand there were 613,731 women giving birth in participating maternity sites, giving an incidence of 1 in 18,598, or 5.4 per 100,000 women giving birth (95 % CI 3.5 7.2 per 100,000) and a maternal mortality of 0.8 per 100,000 women giving birth (95 % CI 0.1-1.5 0.1-1.5,000).
The two sites are - large tertiary maternity hospitals in Sydney (site 1) and Brisbane (site 2).
