Occupational factors and miscarriages in the US fire service: a cross-sectional analysis of women firefighters

Table 2 Age-at-pregnancy standardized prevalence ratios comparing miscarriage among most recent pregnancy of firefighters to US non-firefighters

	Observed events	Expected events	aSPR (95% CI)
Firefighters compared to women from a US cohort of nurses^a
All firefighters (N = 1041)	138	59.2	2.33 (1.96–2.75)
Employment status
Career (n = 892)	100	51.4	1.94 (1.58–2.37)
Volunteer (n = 149)	38	7.8	4.90 (3.47–6.72)
Wildland firefighter status
Structural (n = 685)	115	41.6	2.76 (2.28–3.32)
Wildland/WUI (n = 354)	23	17.4	1.32 (0.84–1.98)
Firefighters compared to California women belonging to a prepaid health plan^b
All firefighters (N = 1041)	138	127.0	1.09 (0.91–1.28)
Employment status
Career (n = 892)	100	108.8	0.92 (0.75–1.12)
Volunteer (n = 149)	38	18.2	2.09 (1.48–2.87)
Wildland firefighter status
Structural (n = 685)	115	83.6	1.38 (1.14–1.65)
Wildland/WUI (n = 354)	23	43.2	0.53 (0.34–0.80)

US United States, aSPR age-at-pregnancy-standardized prevalence ratio, CI confidence interval, WUI wildland urban interface
^a Lawson et al., 2014 (DOI: https://doi.org/10.1016/j.ajog.2011.12.030). Study included 7482 women from the Nurses’ Health Study II who self-reported details about their most recent pregnancy (resulting in miscarriage or livebirth) while working as a nurse between 1993 and 2000
^b Slama et al., 2005 (DOI: https://doi.org/10.1093/aje/kwi097). Study included 5121 pregnancies (resulting miscarriage, stillbirth, or livebirth) belonging to California, US members of the Kaiser Permanente Medical Care Program, with a prenatal appointment between February 1990 and September 1991. Data were abstracted from medical records

ISSN: 1476-069X