Table 2. Clinical risk factors at 15 weeks, and ultrasound scan variables at 20 weeks in logistic regression model for SPTB-IM.

SPTB-IM
	OR	Lower95%	Upper95%
BMI <20	1.46	0.62	3.42
BMI 25–30	1.63	0.96	2.79
BMI >30	1.21	0.63	2.32
Caucasian ethnicity	2.73	0.98	7.60
Marijuana pre-pregnancy	2.34	1.22	4.52
Not feeling better than ever	1.78	0.90	3.51
Having a history of >1 vaginal bleed	2.33	1.08	5.04
Mother with diabetes type 1 or 2	2.19	0.99	4.86
Mother with a history of preeclampsia	2.34	1.30	4.21
Strong family history of low birthweight babies	5.64	1.79	17.80
Abnormal uterine artery Doppler20 wks	2.18	1.20	3.94
Shortest transvaginal cervical lengthin mm	1.05	1.01	1.08

Reference BMI 20–<25.