Table 5.

Odds ratios for an interquartile range change in urinary GLY and AMPA concentrations during pregnancy and spontaneous preterm birth.

Analyte	Crudea			Adjustedb
	Spontaneous preterm [$n$]	Term [$n$]	OR (95% CI)	Spontaneous preterm [$n$]	Term [$n$]	OR (95% CI)
IQR GLYc
Visits 1 and 3 average	23	103	1.67 (0.97, 2.88)	20	97	1.44 (0.73, 2.85)
Visit 1 ($18\pm 2$ wk)	23	142	1.15 (0.72, 1.85)	20	135	1.34 (0.82, 2.20)
Visit 3 ($26\pm 2$ wk)	35	155	1.49 (1.09, 2.05)	32	148	1.45 (1.00, 2.10)
IQR AMPAd
Visits 1 and 3 average	23	103	1.59 (1.10, 2.30)	20	97	1.52 (0.98, 2.35)
Visit 1 ($18\pm 2$ wk)	23	142	0.94 (0.70, 1.28)	20	135	0.98 (0.74, 1.29)
Visit 3 ($26\pm 2$ wk)	35	155	1.76 (1.31, 2.36)	32	148	1.88 (1.35, 2.62)

Note: AMPA, aminomethylphosphonic acid; BMI, body mass index; CI, confidence interval; GLY, glyphosate; IQR, interquartile range; OR, odds ratio.

^aBiomarkers are adjusted for specific gravity using the formula: ${\text{GA}}_{\text{SG}}=\text{GA}\left[\left(1.019–1\right)/\left(\text{SG}-1\right)\right]$, where ${\text{GA}}_{\text{SG}}$ is the SG-adjusted GLY or AMPA concentration ($\mathrm{\mu }\mathrm{g}/\mathrm{L}$); GA is the observed GLY or AMPA concentration; 1.019 is the population median specific gravity; and SG is the specific gravity of the urine sample.

^bModels are adjusted for maternal age, education, prepregnancy BMI, and smoking.

^cIQRs were calculated based on GLY distribution in controls. IQRs were 0.56, 0.52, and 0.54 for Visit 1, Visit 3, and the Visits 1 and 3 average, respectively.

^dIQRs were calculated based on AMPA distribution in controls. IQRs were 0.27, 0.40, and 0.30 for Visit 1, Visit 3, and the Visits 1 and 3 average, respectively.