Table 3.

Results of relative risk regression models^a showing the relationship between maternal TCDD exposure and spontaneous abortion, SWHS, Seveso, Italy, 1976–2016.

		Spontaneous abortion
Exposure	Post-explosion pregnancies	n / Total d	Adj.RR (95% CI)b, c
1976 Serum TCDD	All First	174/ 1,122 79/ 573	0.85 (0.69, 1.05) 0.86 (0.63, 1.17)
Estimated TCDD at Pregnancy	All First	174/ 1,122 79/ 573	0.90 (0.72, 1.12) 0.79 (0.56, 1.13)
Estimated TEQ at Pregnancy	All First	69/ 344 21/ 118	1.27 (0.50, 3.23) 1.13 (0.32, 4.05)

^aResults are for a 10-fold increase in serum TCDD or TEQ.

^bAdjusted for maternal height, pre-explosion history of spontaneous abortion, parity, and maternal age.

^cIn TEQ model, pre-explosion history of spontaneous abortion and parity are omitted by collinearity.

^dTotal excludes ectopic pregnancies (n=15), molar pregnancies (n=2), and voluntary abortions (n=128). However, first pregnancy is defined as the first pregnancy out of the 1,267 postexplosion pregnancies.