Table 1. Unstandardized coefficients (β) and 95% confidence intervals (CI) from gamma GLMM of gestational length (in days) over three time points in pregnancy (with ethnicity as a random effect). Early, mid- and late pregnancy GLMMs using Lactobacillus status (dominated/depleted), as well as an early CST GLMM, which replaces the Lactobacillus covariate with CST. Secretors with Lactobacillus-dominated microbiota (or CST 1) are baseline in the model.

	Early	Mid	Late	Early (CST)
	β (95% CI)	β (95% CI)	β (95% CI)	β (95% CI)
Intercept	3.375 (2.609, 4.142)‡	3.053 (2.302, 3.804)‡	2.894 (2.140, 3.649)‡	3.263 (2.462, 4.064)‡
Maternal age	0.003 (−0.013, 0.019)	0.010 (−0.006, 0.026)	0.013 (−0.003, 0.029)	0.006 (−0.011, 0.022)
BMI	−0.013 (−0.031, 0.006)	−0.007 (−0.024, 0.010)	−0.006 (−0.023, 0.012)	−0.012 (−0.030, 0.007)
Previous PTB§/MTL¶	0.541 (0.353, 0.729)‡	0.339 (0.154, 0.524)‡	0.324 (0.141, 0.506)‡	0.527 (0.330, 0.724)‡
Cervical stitch	0.361 (0.171, 0.552)‡	0.414 (0.248, 0.580)‡	0.224 (0.056, 0.392)†	0.366 (0.175, 0.557)‡
Previous cervical excisional treatment	−0.138 (−0.330, 0.054)	−0.199 (−0.387, –0.011)*	−0.129 (−0.317, 0.059)	−0.152 (−0.348, 0.044)
Secretor ×Lactobacillus	0.617 (0.143, 1.092)*	0.268 (−0.201, 0.737)	0.078 (−0.378, 0.534)
Secretor ×CST 2				na(low sample size)
Secretor×CST 3				0.264 (−0.172, 0.699)
Secretor×CST 4				0.467 (−0.125, 1.060)
Secretor×CST 5				−0.348 (−1.149, 0.454)

*P<0.05.

†P<0.01.

‡P<0.001.

§Preterm birth.

¶Mid-trimester loss.