Objective
The purpose of this study was to determine contraceptive continuation and repeat pregnancy rates in adolescents who are offered immediate postpartum etonogestrel implant (IPI) insertion.
Study Design
Participants in an adolescent prenatal-postnatal program were enrolled in a prospective observational study of IPI insertion (IPI group, 171) vs other methods (control group, 225). Contraceptive continuation and repeat pregnancies were determined.
Results
Implant continuation at 6 months was 96.9% (156/161 participants); at 12 months, the continuation rate was 86.3% (132/153 participants). At 6 months, 9.9% of the control participants were pregnant (21/213); there were no IPI pregnancies. By 12 months, 18.6% of control participants (38/204) experienced pregnancy vs 2.6% of IPI recipients (4/153; relative risk, 5.0; 95% confidence interval [CI], 1.9–12.7). Repeat pregnancy at 12 months was predicted by not receiving IPI insertion (odds ratio, 8.0; 95% CI, 2.8–23.0) and having >1 child (odds ratio, 2.1; 95% CI, 1.1–4.3; P = .03).
Conclusion
IPI placement in adolescents has excellent continuation 1 year after delivery; rapid repeat pregnancy is significantly decreased compared with control participants.
Among adolescents who give birth, 12-49% are pregnant again within 1 year. Adolescents who have ≥2 children within 5 years are more likely to rely on welfare, forgo their education, and bear additional children in a short time. Compared with first teenage birth, a second almost triples the risk of preterm delivery and stillbirth.
The levonorgestrel subdermal implant (Norplant; Wyeth-Ayerst International Inc, Wayne, PA) has been associated with prevention of rapid repeat pregnancy (RRP) in adolescents. In the same study, social interventions such as frequent clinic visits, contact with supportive healthcare providers, and return to school did not reduce the risk of another pregnancy within 2 years. In another study, continuation rates for the levonorgestrel implant were significantly higher than those of depot medroxyprogesterone acetate (DMPA) and oral contraceptive pills (OCPs) in adolescents. This implant was withdrawn voluntarily from the market in 2002 for nonmedical reasons; currently, the etonogestrel implant (Implanon; Merck, Darmstadt, Germany) is the only subdermal contraception available in the United States. This implant offers contraceptive effectiveness with an excellent safety profile for up to 3 years.
The US Medical Eligibility Criteria for Contraceptive Use assigns a category 1 rating (no restrictions) to the use of the etonogestrel implant by adolescents. Use in breastfeeding women <4 weeks after childbirth is classified as category 2 (advantages generally outweigh risks) because of theoretic concerns regarding milk production and infant development, although evidence for progestin use (including the etonogestrel implant) while breastfeeding has been reassuring consistently.
Theoretically, the immediate postpartum period is an ideal time for etonogestrel implant insertion in adolescents; however, data on continuation and repeat pregnancy rates in the immediate postpartum adolescent population are scant. Investigators in Australia reported that, when the etonogestrel implant was inserted at 6 weeks after delivery, the teenagers who used the implant were significantly less likely than those who used OCPs, DMPA, barrier methods, or nothing to become pregnant within 24 months after delivery. A small noncomparative study concluded that the implant is well accepted and maintained by adolescents when inserted within 6 months of delivery. Implant insertion within 24-48 hours of delivery was not associated with any deleterious maternal effects or decreased fetal weight gain in a pilot comparative study of 40 women after delivery.
The aim of this study was to compare contraceptive continuation and repeat pregnancy rates in adolescents who received postpartum subdermal contraception before hospital discharge with postpartum adolescents who initiated other contraceptive methods after delivery. We hypothesized that immediate postpartum implant (IPI) initiators would have significantly higher rates of consistent contraception use and significantly lower rates of repeat pregnancy at 6 and 12 months compared with initiators of any other contraceptive method, including long-acting methods that were initiated >4 weeks after delivery.
Materials and Methods
In this prospective observational study, all adolescents (defined by the Centers for Disease Control and Prevention as age 13-24 years ) who were attending the Colorado Adolescent Maternity Program (CAMP) and who delivered at the University of Colorado Hospital over the 18-month period of June 1, 2008, to November 30, 2009, were eligible for inclusion in the study cohort. All of the patients expressed the desire to prevent pregnancy for at least 1 year after delivery. Exclusion criteria included contraindications to etonogestrel use, relinquishing the child for adoption, stillbirth, being delivered at a different hospital, and having no postpartum visits at the CAMP.
CAMP is a comprehensive, multidisciplinary, adolescent-oriented program that provides prenatal, delivery, postnatal, and infant care that emphasizes consistent contraceptive use and goal-oriented future planning regarding school completion, job training, and parenting. The importance of consistent contraceptive use is emphasized at prenatal and postpartum visits. Contraceptive counseling begins at the first prenatal visit and is discussed at most subsequent visits by the midwife and the case manager. Counseling occurs in both individual and group settings and is supported by written materials. During the period of this study, providers emphasized that the subdermal implant could be received immediately after delivery.
Each patient is encouraged to have a firm contraceptive plan by 32 weeks gestation; however, group assignment was determined by whether the patient had an implant placed before hospital discharge. After delivery, patients continue care in the CAMP clinic where mothers and children receive follow-up care together. Adolescent mothers thus are seen more frequently than in traditional care models and have many opportunities to initiate contraception. Participants in CAMP provide informed consent for noninvasive procedures that include medical record review, surveys, and phone contact under an institutional review board–approved protocol that allows minors to consent for themselves.
During the period of this study, young women who were enrolled in CAMP who elected to have an immediate subdermal implant and who received this implant before hospital discharge were included in the IPI group. A few participants elected immediate placement but were unable to receive it because of a lack of provider availability; all of those participants had placement within 4 weeks after delivery and were included in the IPI group. Those who initiated any other contraceptive method according to standard clinical protocols were included in the control group. The control group consisted of participants who chose no contraception, condoms, implant insertion at >4 weeks after delivery, levonorgestrel-intrauterine system or copper-T 380A (IUD) insertion any time >6 weeks after delivery (the standard timing for postpartum insertion in our clinical setting during the study period), DMPA, progestin-only pills that were initiated at any time after delivery, and combined hormonal contraception (pills, patch, ring) that was started at any time after 4 weeks after delivery. DMPA was not available before discharge during the study period. All participants remained in the IPI group or the control group based on the contraceptive method that they selected before discharge home.
The manufacturer currently recommends insertion of the etonogestrel implant in lactating women after the fourth postpartum week. All participants who elected to follow the immediate etonogestrel implant protocol were informed that this practice differs from the package insert recommendations.
All participant demographic and encounter-related variables are maintained in the Electronic Report on Adolescent Pregnancy. Participants’ electronic medical records were reviewed to determine contraceptive use, discontinuation of contraceptive methods, reasons for the discontinuation, and pregnancy at various time points of interest. Participants with incomplete data were contacted by telephone. Up to 3 attempts were made. Participants who were reached by phone were administered a standard questionnaire that assesses birth control method continuation and pregnancy occurrence. Data from the electronic medical record and phone interviews were combined to create the most complete measurement of contraceptive use.
The primary outcome was repeat pregnancy by 12 months after delivery. This was documented in the medical record or by participant report during the phone questionnaire. We hypothesized the 1-year repeat pregnancy rate in our population would decrease from 15% in the control group to 5% in the IPI group. To demonstrate this difference with an alpha of .05 and a power of 0.8, 160 women were required in each group.
Consistent contraception was the secondary outcome. For this study, we defined consistent contraception as maintaining ≥1 highly effective contraceptive method(s) for 80% of the year of observation. Highly effective contraceptive methods included all hormonal methods or the copper T380 IUD. The year of observation for this endpoint was defined as beginning at 6 weeks after delivery and ending at 13.5 months after delivery. This time period was chosen because some contraceptive methods were not available to patients at <6 weeks after delivery. We chose 80% as a conservative endpoint because many young women in this population have periods of abstinence during which they discontinue contraception yet are not at risk of pregnancy.
Summary statistics were used to describe the population as well as the outcomes. The Student t test was used to compare means; the χ 2 test was used to compare proportions, and the Fisher’s exact test was used for small cell sizes. Univariable analysis and multivariable logistic regression were performed to determine significant variables that influenced repeat pregnancy. Variables that were significant ( P < .05) in the univariable analyses were included in the logistic regression. SPSS statistical software (version 19.0.0; SPSS Inc, Chicago, IL) was used for all the analyses. The study was approved by the Colorado Multiple Institutional Review Board.
Results
Over the 18-month study period, 420 young women received prenatal care and delivered in the CAMP program. Twenty-four patients were excluded from the cohort because of stillbirth (n = 4), relinquishing the infant for adoption (n = 2), or delivery at a different hospital that precluded immediate implant placement (n = 18). Thus, 396 CAMP patients were delivered and eligible for the study cohort. No one declined study participation. The subject demographics are described in Table 1 . Most were mid-to-late adolescents (mean age, 18.6 years; range, 13–23 years) and unmarried. The population was ethnically diverse. Two hundred forty-three subjects (61.4%) had obtained a graduate equivalency degree or were in at the appropriate grade level in school. Seventy-seven percent of the young women were primiparous.
| Variable | Control subjects (n = 225) | Immediate postpartum implantation (n = 171) | P value or odds ratio (95% CI) |
|---|---|---|---|
| Age at conception, y a | 18.7 ± 1.8 | 18.5 ± 1.6 | .22 |
| Race/ethnicity, % | |||
| Hispanic | 40.7 | 44.8 | Reference |
| Black | 49.7 | 43.5 | 0.8 (0.5–1.2) |
| White | 32.0 | 31.5 | 1.0 (0.6–1.7) |
| Gravidity, % | .11 | ||
| Primigravid | 61.3 | 69.0 | |
| ≥2 pregnancies | 38.7 | 31.0 | |
| Parity, % | .02 | ||
| Primiparous | 72.0 | 82.5 | |
| ≥2 live births | 28.0 | 17.5 | |
| Previous induced abortions, % | 4.4 | 3.5 | .64 |
| Previous spontaneous abortions, % | 14.7 | 15.2 | .88 |
| Body mass index, kg/m 2 a | 24.5 ± 5.8 | 24.1 ± 5.1 | .50 |
| Under weight: <18.5 kg/m 2 , % | 12.5 | 20.0 | 1.8 (0.8–3.8) |
| Average weight: 18.5–24.9 kg/m 2 , % | 56.5 | 49.0 | Reference |
| Overweight/obese: ≥25.0 kg/m 2 , % | 38.5 | 44.1 | 1.3 (0.8–2.0) |
| In school, graduated, or has graduate equivalency degree, % | 73.4 | 71.6 | .71 |
| Has a relationship with the father of the child, % | 85.3 | 87.9 | .47 |
A total of 171 adolescent girls (43.2%) received immediate postpartum etonogestrel implants. One hundred fifty-eight of them (92.4%) underwent insertion on the Labor and Delivery unit before discharge home after delivery; the remaining 13 the young women intended to have immediate insertion but, because of no trained provider available on Labor and Delivery, received it in the CAMP clinic within 4 weeks of delivery.
The 225 subjects (56.8%) who delivered within the study period but did not choose IPI insertion were classified as control subjects ( Figure ). There were no significant differences in baseline characteristics between the 2 study groups aside from parity ( Table 1 ); the IPI group members were more likely to be primiparous (82.5% vs 72%; P = .01). Lost to follow-up rates were similar between groups at both 6 months (IPI group, 5.8%; control group, 5.3%; P = .8) and 12 months (IPI group, 10.5%; control group, 9.3%; P = .7). Women who were lost to follow-up evaluation did not differ from the rest of the cohort on any demographic or reproductive factors.
In the IPI group, 96.9% of the subjects (156/161) continued implant use at 6 months after delivery, and 86.3% of the subjects (132/153) continued use at 12 months after delivery. Of the 21 IPI participants who discontinued implant use at <12 months, 12 participants noted irregular bleeding as a reason for discontinuation, and 7 participants reported this as the sole reason for discontinuation. Nine participants cited >1 reason for discontinuation ( Table 2 ). Consistent contraception use (defined as maintaining ≥1 contraceptive methods for 80% of the observation period) was 99.4% in the IPI group at 6 months after delivery vs 54.9% among control subjects ( P < .001). At 12 months, consistent contraception was 94.3% in the IPI group and 52.3% in the control group ( P < .001).
| Reason | <6 mo after delivery a (n) b | 6–12 mo after delivery c (n) b |
|---|---|---|
| Irregular bleeding | 2 | 10 |
| Weight gain | 2 | 0 |
| Headaches | 2 | 2 |
| Rash | 1 | 0 |
| Chest pain | 1 | 0 |
| Moodiness | 0 | 4 |
| Arm pain | 0 | 3 |
| Pregnancy desire | 0 | 2 |
| Cramps | 0 | 2 |
| Acne | 0 | 2 |
| Nausea | 1 | 0 |
| Hair loss | 1 | 0 |
| Nonspecific complaints | 0 | 2 |
b Total of reasons exceeds the number of discontinuers because some participants cited >1 reason for discontinuation;
Participants could change contraceptive methods throughout the course of the study. In the control group and among IPI participants who discontinued the implant, a variety of contraceptive strategies were followed. Method distribution at 8 weeks, 6 months, and 12 months after delivery are presented in Table 3 . Notably, 42.7% of the control participants (91/213) were using long-acting methods (either implants or IUDs) at 6 months after delivery, and 48.6% of them (89/183) were using these methods at 12 months after delivery.
| Contraceptive method | Control subjects, n (%) a | Immediate postpartum implantation, n (%) b | ||||
|---|---|---|---|---|---|---|
| 8 wk | 6 mo | 12 mo | 8 wk | 6 mo | 12 mo | |
| Implantation | 14 (6.2) | 32 (16.7) | 35 (21.1) | 171 (100) | 156 (96.8) | 132 (86.3) |
| Intrauterine device | 16 (7.1) | 56 (29.2) | 51 (30.7) | 0 | 1 (0.6) | 6 (3.9) |
| Depot medroxyprogesterone acetate | 34 (15.1) | 36 (18.8) | 31 (18.7) | 0 | 1 (0.6) | 5 (3.3) |
| Oral contraceptive pills | 16 (7.1) | 12 (6.3) | 11 (6.6) | 0 | 2 (1.2) | 3 (2.0) |
| Vaginal ring | 3 (1.3) | 4 (2.1) | 2 (1.2) | 0 | 0 | 0 |
| Contraceptive patch | 1 (0.4) | 3 (1.6) | 3 (1.8) | 0 | 0 | 0 |
| Condoms | 19 (8.4) | 14 (7.3) | 10 (6.0) | 0 | 1 (0.6) | 3 (2.0) |
| Emergency contraception | 4 (1.8) | 0 | 0 | 0 | 0 | 0 |
| Withdrawal | 3 (1.3) | 1 (0.5) | 0 | 0 | 0 | 0 |
| Tubal ligation | 3 (1.3) | 3 (1.6) | 3 (1.8) | 0 | 0 | 0 |
| None | 112 (49.8) | 31 (16.1) | 20 (12.0) | 0 | 1 (0.6) | 0 |
| T otal | 225 | 192 | 166 | 171 | 161 | 149 |
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