Table 2:

Associations between baseline characteristics and low-lying IUD position (N=168)

	OR (95% CI) N=28	aOR (95% CI) N=140	P-value^a
Age at IUD insertion
Continuous (years)	0.9 (0.83, 1.07)	1.0 (0.86, 1.12)	0.75
Categorical
20-26	1.0 (ref)	1.0 (ref) 0.7 (0.30, 1.70)	0.45
27-34	0.7 (0.29, 1.47)
Education
≤High school or GED	2.9 (1.10, 7.59)	3.1 (1.14, 8.55)	0.03
>High school or GED	1.0 (ref)	1.0 (ref)
Body mass index (kg/m2)
Continuous (1 unit)	1.1 (1.03, 1.13)	1.1 (1.03, 1.14)	0.002
Categorical
<35	1.0 (ref)	1.0 (ref) 3.0 (1.26, 7.20)	0.01
≥35	3.1 (1.30, 7.28)
Parity ^b
0	1.0 (ref)	1.0 (ref)	0.34
≥ 1	0.6 (0.15, 2.26)	0.5 (0.12, 2.29)
Retroverted uterus
No	1.0 (ref)	1.0 (ref)	0.76
Yes	1.1 (0.36, 3.04)	1.2 (0.39, 3.69)
Uterine volume (cc)
Continuous (1cc)	1.0 (1.00, 1.01)	1.0 (1.00, 1.01)	0.15
Categorical (quartiles)
41-82	1.0 (ref)	1.0 (ref)	0.31
83-107	1.7 (0.52, 5.84)	2.6 (0.72, 9.56)
108-136	1.0 (0.27, 3.75)	1.0 (0.26, 4.20)
	2.3 (0.72, 7.47)	2.3 (0.67, 7.93)
137-401
Fibroids at enrollmen ^b
No	1.0 (ref)	1.0 (ref) 0.6 (0.15, 2.10)	0.39
Yes	0.6 (0.16, 2.00)
Type of current IUD
Mirena®	1.0 (ref)	1.0 (ref) 1.1 (0.41, 2.79)	0.88
Paragard®	1.1 (0.45, 2.74)

OR: Odds Ratio, 95% CI: 95% Confidence Interval, aOR: Odds Ratio adjusted for continuous BMI and education, except BMI variables were only adjusted for education and education was only adjusted for continuous BMI.

p-value for overall effect of variable;

Results based on limited sample size (one of the categories had only 3 low-lying IUDs).