Three-year continuation of reversible contraception




Materials and Methods


In 2007, the Contraceptive CHOICE Project (CHOICE) began recruiting women for a prospective observational cohort study. The goal of the study was to reduce the unintended pregnancy rate in the St. Louis, MO, area by promoting the most effective methods of contraception and eliminating the cost barrier to all forms of contraception. The methods have been reported in detail but are described briefly below. The Human Research Protection Office at Washington University in St. Louis approved the study protocol before study recruitment.


Participants were referred to CHOICE through their health care providers, posted flyers, and word of mouth. Recruitment sites included local health care centers, 2 abortion care providers, and a university-associated clinical research center. Inclusion criteria included women who (1) were 14–45 years of age, (2) desired reversible contraception and were willing to start a new method, (3) were sexually active with a male partner or intended to be within 6 months, (4) who lived in or received reproductive care in the St. Louis area, and (5) were able to consent in English or Spanish. Women were excluded if they desired pregnancy in the next 12 months or were had had hysterectomy or permanent sterilization. Recruitment of the 9256 participants began in 2007 and was completed in 2011. All participants provided written informed consent before study enrollment.


All potential participants heard a standardized introduction to LARC methods; upon enrollment, they received additional contraceptive counseling. LARC methods included the LNG-IUD, the Cu-IUD, and the 3-year subdermal implant. The contraceptive counseling reviewed all reversible methods in order of effectiveness from most to least effective. After a baseline interview, participants completed screening for sexually transmitted infections, received their contraceptive of choice at no cost, and were followed for 2 or 3 years, depending on the timing of enrollment. Follow-up telephone interviews were performed at 3 and 6 months then every 6 months thereafter for the duration of study participation. At the enrollment visit, each participant chose her baseline method. When possible, they would start that method immediately. In certain cases (such as when pregnancy could not be ruled out reasonably), the patient received a bridge method until they returned for the initiation of their chosen method. Bridge methods included depot medroxyprogesterone acetate (DMPA), oral contraceptive pills (OCPs), combined contraceptive patch, vaginal ring, or condoms. Participants were able to switch methods at any time during the follow-up period. For the purposes of this analysis, if a participant switched her method, we considered this a discontinuation of the baseline method. Women who received the implant were told that it was approved for up to 3 years of use. If a participant had the device removed and reinserted within the same month, it was not considered a discontinuation. Follow-up interviews focused on method use, complaints, complications, side-effects, method troubleshooting, reasons for method discontinuation, and pregnancies. CHOICE participants have unrestricted access to device removal, even after CHOICE ended.


This analysis included women who chose a LARC or a non-LARC method (DMPA, OCPs, contraceptive patch, or vaginal ring), started using their method by their 3-month survey, and completed their 36-month follow-up survey or had another data source that verified continuation or discontinuation at 3 years. Continuation rates at 3 years were estimated for each method. LARC methods were compared with non-LARC methods and were stratified by age (14–19 and 20–45 years old). Descriptive analyses were performed to describe demographic characteristics of participants with the use of chi-square test or t -test, where appropriate. Normality was assessed for continuous variables. The time-to-event for this survival analysis was calculated from method initiation to the time point when the participant discontinued her contraceptive method. If she was lost to follow up, she was censored at her last time of contact with CHOICE. Participants were censored if they discontinued a contraceptive method to attempt pregnancy. Kaplan-Meier survival functions were used to estimate continuation rates among different methods. We used Cox proportional hazard models to estimate hazard ratios for risk of contraceptive method discontinuation for characteristics that were associated with discontinuation. We defined confounders as variables that changed the estimate of hazard ratio for a contraceptive method by ≥10% when they were included in the model. Confounding variables and significant factors from univariable analysis or variables that were set a priori were included in the final multivariable model to evaluate their effect size. The alpha level was set at .05. Stata software (version 11; StataCorp, College Station, TX) was used for all analyses.




Results


Of 9256 CHOICE participants, the first 5090 were observed for 3 years. In this cohort, 382 women were excluded because they did not start their chosen baseline method by the 3-month survey. There were a total of 4708 participants (92%) who were observed for 3 years and were included in this analysis. A flow diagram of included participants is shown in Figure 1 . There were 185 women (4%) who were censored because of discontinuation for desire to conceive or pregnancy.




Figure 1


Study inclusion

Flow chart of participants included in analysis.

Diedrich. Three-year contraceptive continuation. Am J Obstet Gynecol 2015 .


Demographic and reproductive characteristics are shown in Table 1 . Mean age of participants in this analysis was 25 years; 48% were black; 35% had a high school education or less; 34% received public assistance; 44% had no health insurance; and 12% reported public insurance. Overall, 47% were nulliparous, and 66% reported at least 1 unintended pregnancy at baseline. There were 662 adolescents in our cohort: 405 used LARC methods and 257 used non-LARC methods. In our stratified analysis by LARC vs non-LARC methods, we noted that LARC users were older, had higher parity, were more likely to have public insurance, and were more likely to have a history of an unintended pregnancy.



Table 1

Baseline characteristics of analytic sample, stratified by contraceptive method and age








































































































































































































































Variable Overall (n = 4708) Non-long-acting reversible contraceptive method (n = 1505) Long-acting reversible contraceptive method (n = 3203) P value
Age, y a 25.2 ± 5.7 24.0 ± 5.0 25.7 ± 5.9 < .001
Race, n (%) .668
Black 2243 (47.7) 723 (48.1) 1520 (47.5)
White 2100 (44.6) 659 (43.8) 1441 (45.0)
Other 364 (7.7) 122 (8.1) 242 (7.6)
Education, n (%) < .001
≤High school 1661 (35.3) 472 (31.4) 1189 (37.1)
Some college 1987 (42.2) 666 (44.3) 1321 (41.3)
College graduate 1058 (22.5) 366 (24.3) 692 (21.6)
Body mass index, n (%) < .001
Underweight 144 (3.1) 72 (4.9) 72 (2.3)
Normal 1895 (41.2) 718 (49.2) 1177 (37.4)
Overweight 1206 (26.2) 333 (22.8) 873 (27.8)
Obese 1357 (29.5) 336 (23.0) 1021 (32.5)
Low socioeconomic status, n (%) b < .001
No 2088 (44.4) 776 (51.6) 1312 (41.0)
Yes 2618 (55.6) 728 (48.4) 1890 (59.0)
Insurance, n (%) < .001
None 2031 (43.5) 683 (46.0) 1348 (42.4)
Private 2081 (44.6) 711 (47.9) 1370 (43.0)
Public 556 (11.9) 91 (6.1) 465 (14.6)
Parity, n (%) < .001
0 2225 (47.3) 988 (65.6) 1237 (38.7)
1 1150 (24.4) 290 (19.3) 860 (26.8)
2 819 (17.4) 149 (9.9) 670 (20.9)
3+ 514 (10.9) 78 (5.2) 436 (13.6)
Unintended pregnancies, n (%) < .001
0 1599 (34.0) 704 (46.9) 895 (28.0)
1 1292 (27.5) 423 (28.2) 869 (27.2)
2 780 (16.6) 188 (12.5) 592 (18.5)
3+ 1027 (21.9) 187 (12.5) 840 (26.3)
History of abortion at baseline, n (%) < .001
No 2870 (61.0) 969 (64.4) 1901 (59.4)
Yes 1838 (39.0) 536 (35.6) 1302 (40.6)
History of sexually transmitted infection at baseline .011
No 2869 (61.0) 957 (63.6) 1912 (59.7)
Yes 1836 (39.0) 547 (36.4) 1289 (40.3)

Diedrich. Three-year contraceptive continuation. Am J Obstet Gynecol 2015 .

a Data are given as mean ± SD


b Includes trouble paying for basic necessities or receiving government subsidies in the form of food stamps or welfare.



Continuation at 1, 2, and 3 years for each contraceptive method is listed in Table 2 . We stratified continuation by LARC and non-LARC methods. At 3 years, continuation was 67.2% among LARC users and 31.0% among non-LARC users ( P < .001) ( Figure 2 ). The highest continuation was among IUD users, with 69.8% continuation among LNG-IUD users and 69.7% among Cu-IUD users. Non-LARC methods had lower rates of continuation that range from 28–33% at 3 years. Among adolescents 14–19 years old, 3-year continuation was lower for all methods compared with women 20–45 years old and was lowest among non-LARC methods (52.6% for adolescents who used LARC and 23.1% for non-LARC methods). By 3 years, 54.6% of adolescents continued the LNG-IUD; 49.5% continued the Cu-IUD, and 50.8% continued the subdermal implant.



Table 2

Kaplan-Meier estimates of 1-, 2-, and 3-year continuation of baseline method chosen
































































































Variable Continuation, % (95% confidence interval)
1 Year 2 Year 3 Year
Overall 76.7 (75.4–77.9) 64.2 (62.6–65.5) 56.2 (54.5–57.5)
Intrauterine device
Levonorgestrel 87.3 (85.8–88.6) 76.7 (74.8–78.5) 69.8 (67.6–71.8)
Copper 84.3 (80.7–87.3) 76.2 (72.1–79.9) 69.7 (65.1–73.7)
Implant 81.7 (78.3–84.7) 68.7 (64.7–72.3) 56.2 (51.8–60.3)
Depot medroxyprogesterone acetate 57.1 (51.6–62.3) 39.3 (33.8–44.7) 33.2 (26.9–37.7)
Oral contraceptive pill 60.6 (56.3–64.6) 42.2 (37.9–46.5) 31.5 (27.3–35.8)
Ring 54.3 (49.7–58.6) 37.5 (33.1–41.9) 30.0 (25.8–34.4)
Patch 48.2 (38.3–57.4) 35.0 (25.7–44.5) 28.4 (19.5–37.9)
Long-acting reversible contraceptive 85.8 (84.5–87.0) 75.2 (73.6–76.7) 67.2 (65.4–68.9)
Non-long-acting reversible contraceptive 55.8 (54.2–59.4) 39.5 (36.9–42.1) 31.0 (28.5–33.5)
Adolescents, 14–19 y
Long-acting reversible contraceptive 82.1 (78.0–85.6) 68.0 (63.0–72.5) 52.6 (47.2–57.7)
Non-long-acting reversible contraceptive 48.5 (42.1–54.6) 34.5 (28.5–40.6) 23.1 (17.6–29.0)
Adults, 20–45 y
Long-acting reversible contraceptive 86.3 (85.0–87.6) 76.2 (74.5–77.8) 69.2 (67.4–71.0)
Non-long-acting reversible contraceptive 58.6 (55.7–61.3) 40.5 (37.7–43.4) 32.6 (29.8–35.4)

Diedrich. Three-year contraceptive continuation. Am J Obstet Gynecol 2015 .



Figure 2


Contraceptive continuation

Kaplan-Meier Survival Curve of long-acting reversible contraceptive methods and non-long-acting reversible contraceptive methods.

LARC , long-acting reversible contraceptive method.

Diedrich. Three-year contraceptive continuation. Am J Obstet Gynecol 2015 .


Univariable analysis of risk factors for discontinuation is shown in Table 3 ; the multivariable model is shown in Table 4 . After adjustment for age, race, education, low socioeconomic status, parity, and history of sexually transmitted infection, the hazard ratio for discontinuation was >3 times higher among non-LARC method users (adjusted hazard ratio, 3.08; 95% confidence interval, 2.80–3.39) than LARC users. Participants 14-19 years old at baseline were more likely to discontinue at 3 years compared with women ≥20 years old (adjusted hazard ratio, 1.33; 95% confidence interval, 1.16–1.53). Compared to those with a high school education or less, college graduates reported a lower risk of discontinuation (adjusted hazard ratio, 0.85; 95% confidence interval, 0.74–0.98).



Table 3

Univariable analysis of risk factors for discontinuation of baseline contraceptive method at 3 years














































































































































































Variable Univariable model
Hazard ratio 95% Confidence interval
Contraceptive method
Oral contraceptive pill Reference
Intrauterine device
Levonorgestrel 0.30 0.27–0.35
Copper 0.31 0.26–0.38
Implant 0.48 0.40–0.56
Depot medroxyprogesterone acetate 1.01 0.85–1.20
Patch 1.21 0.94–1.56
Ring 1.12 0.96–1.30
Age, y
14–19 1.55 1.38–1.74
20+ Reference
Race
Black 1.20 1.09–1.32
White Reference
Other 1.30 1.10–1.54
Education
≤High school Reference
Some college 0.93 0.84–1.03
College graduate 0.82 0.73–0.93
Body mass index
Underweight 1.18 0.92–1.51
Normal Reference
Overweight 0.91 0.82–1.02
Obese 0.78 0.70–0.87
Low socioeconomic status a
No Reference
Yes 0.95 0.87–1.04
Insurance
None 1.07 0.97–1.18
Commercial Reference
Public 1.04 0.90–1.20
Parity
0 1.38 1.27–1.51
1+ Reference
Previous unintended pregnancies
0 Reference
1+ 0.79 0.72–0.87
History of sexually transmitted infection
No Reference
Yes 1.13 1.03–1.24

Diedrich. Three-year contraceptive continuation. Am J Obstet Gynecol 2015 .

a Defined as trouble paying for basic needs (food, housing, medical care, transportation) or receiving government aid (food stamps, welfare).


May 5, 2017 | Posted by in GYNECOLOGY | Comments Off on Three-year continuation of reversible contraception

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