. Author manuscript; available in PMC: 2014 May 2.

Published in final edited form as: Am J Obstet Gynecol. 2012 Apr 6;206(6):479.e1–479.e9. doi: 10.1016/j.ajog.2012.04.012

Table 3.

Knowledge of Effectiveness of Chosen Contraceptive Method (n=4,144)

Contraceptive Method Chosen	n	% of Cohort using this method	% Correctly Estimated Effectiveness of Chosen Method	RR_adj (95% CI) Correct Estimation of Chosen Method^†
LNG-IUD	1,958	47.5	72.2	6.9 (5.6-8.5)
Copper IUD	447	10.8	72.8	7 (5.7-8.7)
Implant	541	13.1	61.7	5.9 (4.7-7.3)
DMPA	316	7.7	22.2	2.0 (1.5-2.7)
Pill/Patch/Ring	880	20.9	11.8	Reference

^†

Multivariable model Poisson regression with robust error variance adjusted for age, education and prior method use