1Demographic characteristics of cases and controls were compared using t-tests for continuous variables and chi-squared tests for categorical variables.
2Values are median and inter-quartile range and exclude missing values
3There were 9 live births with birth weight (g) < 500. The accepted range for birth weights of live births are 500-6000g.
4Difference in education status is due to a reduced rate of maternal form completion in fetal death cases as compared to controls.
5This difference is due to 1) father’s education was available for all years during the period 1978-2016 from birth certificates; but father’s education was only available for the years 1978-2003 from fetal death certificates. 2) fathers are less likely reported in fetal death certificates
Figure S1 . STROBE diagram showing inclusion and exclusion criteria for relatives of parents of stillbirth cases and controls.