Table 4.

Main effects and interactions of study arm, age group (adolescent 18–19 years vs. young adults 20–25 years), and parity (nulliparous vs. parous) on LARC initiation

	Initiated LARC (n = 1,478)
	Model 1: main effects		Model 2: interaction (intervention by adolescent)		Model 3: interaction (intervention by nulliparous)
	aHR	[95% CI]	aHR	[95% CI]	aHR	[95% CI]
Intervention	1.45	[1.03–2.03]*	1.44	[1.00–2.08]*	1.29	[.83–2.01]
Age group
Adolescent (18–19 years)	.94	[.69–1.27]	.93	[.56–1.54]	.94	[.69–1.27]
Intervention by adolescent interaction	—	—	1.01	[.54–1.89]	—	—
Parity
Nulliparous	.65	[.48–.90]**	.65	[.48–.90]**	.58	[.38–.90]*
Intervention by nulliparous interaction	—	—	—	—	1.22	[.73–2.03]

^*p ≤ .05;

^**p ≤ .01.

Models also include race/ethnicity, multiple sexual partners, insurance status, pregnancy intentions, LARC use prior to study enrollment, practice setting, and family planning Medicaid expansion.

CI = confidence interval.