Table 5.

Adjusted Cox proportional hazards regression of baseline characteristics associated with IUD expulsion stratified by IUD type^*

	Levonorgestrel IUD			Copper IUD
	N	HR	95% CI	N	HR	95% CI
Age 14–19 years	439	2.26	1.68, 3.06	90	3.06	1.75, 5.33
Age ≥ 20 years	3780	Ref	Ref	1094	Ref	Ref
White/Other race	2192	Ref	Ref	740	Ref	Ref
Black race	2027	1.32	1.03, 1.68	444	0.92	0.56, 1.49
BMI <30	2776	Ref	Ref	804	Ref	Ref
BMI ≥ 30	1401	1.27	1.02, 1.60	366	1.16	0.72, 1.86
Married/living with a partner	1511	0.85	0.67, 1.08	483	0.91	0.58, 1.45
Single/separated/divorced/Widowed	2707	Ref	Ref	699	Ref	Ref
Low socioeconomic status	2445	1.48	1.13, 1.92	677	0.83	0.53, 1.31
Nulliparous	1690	0.59	0.44, 0.78	492	1.11	0.67, 1.84
Heavy periods	961	1.64	1.30, 2.06	205	1.73	1.08, 2.78
Immediate postabortion insertion	749	1.33	1.03, 1.71	168	1.01	0.55, 1.83

^*Model adjusted for age 14–19, race, obesity, marital status, low socioeconomic status, nulliparity, self-reported heavy periods, and immediate postabortion placement.

IUD – intrauterine device; BMI –body mass index;