Her Body Guide

Science-based guidance for women for their bodies

June 16, 2025

Contraceptive Implants: The Science of Subdermal Birth Control

Contraceptive implants represent the most effective reversible form of birth control available today, with over 99.95% efficacy in preventing pregnancy. Used by more than 11 million women worldwide, these small, flexible rods provide continuous contraceptive protection for three years through sustained hormone release. This comprehensive guide examines the biological mechanisms, insertion procedures, side effects profile, global availability, and the complex endocrinology underlying subdermal contraceptive technology.

The Evolution of Implantable Contraception

From Laboratory Discovery to Clinical Revolution: 1960s-1980s

The development of contraceptive implants began in 1966 when Sheldon Segal at the Population Council recognized that sustained hormone release could provide long-term contraception without daily user intervention. Initial research focused on silicone rubber capsules containing various progestins, leading to revolutionary advances in controlled drug delivery systems.

The first generation implant system, Norplant, contained six levonorgestrel-filled silicone capsules providing five years of contraception. Despite its effectiveness, the six-rod system required complex insertion techniques and experienced high removal complication rates, necessitating development of improved single-rod systems.

Norplant: The Pioneer System (1991-2002)

Norplant's FDA approval in 1990 marked the first long-acting reversible contraceptive available in the United States. The system consisted of six flexible silicone capsules, each containing 36mg levonorgestrel, implanted subdermally in the upper arm.

Clinical trials spanning 55,000 woman-years demonstrated Norplant's remarkable 99.5% contraceptive efficacy. However, the complex six-capsule design led to difficult removals in 2-6% of cases, with some procedures requiring surgical referral and leaving permanent scarring.

Norplant's Clinical Legacy and Withdrawal

1991-1996: Peak usage with 500,000+ American women using Norplant
1995-1999: Legal challenges over inadequate informed consent and removal complications
2000: Class action lawsuits citing failure to warn about side effects
2002: Norplant withdrawn from US market due to manufacturing issues and liability concerns

Second Generation: Implanon Development

Learning from Norplant's limitations, researchers at Organon developed Implanon, a single-rod system containing 68mg etonogestrel in an ethylene vinyl acetate (EVA) core surrounded by an EVA copolymer rate-controlling membrane.

Technological Advances in Implanon

Implanon's single 4cm rod eliminated complex multi-capsule insertion and removal procedures. The etonogestrel-EVA matrix provided more predictable hormone release kinetics, while the radiopaque barium sulfate core allowed X-ray visualization if localization became necessary.

Implanon received European approval in 1998 and demonstrated superior safety profiles compared to Norplant. However, rare cases of non-palpable implants led to development of Nexplanon, featuring enhanced radiopacity for improved localization and removal procedures.

Current Technology: Nexplanon and Global Variants

Nexplanon: The Current Standard

Nexplanon, approved by the FDA in 2011, represents the most advanced single-rod contraceptive implant available globally. The 4cm flexible rod contains 68mg etonogestrel in a core of ethylene vinyl acetate copolymer surrounded by an EVA rate-controlling membrane.

Nexplanon provides over 99.95% contraceptive efficacy across three years, making it more effective than surgical sterilization. Clinical studies involving over 923 women demonstrated zero pregnancies during 20,648 exposure months when properly inserted.

Enhanced Radiopacity and Safety Features

Unlike Implanon, Nexplanon contains barium sulfate throughout the core, making the entire rod radiopaque and visible on X-ray, ultrasound, CT, and MRI imaging. This enhancement dramatically reduces risks associated with non-palpable or deeply inserted implants requiring surgical removal.

Global Availability and Brand Variations

Contraceptive implants are available in over 60 countries under various brand names, with regional regulatory differences affecting availability and insertion protocols.

International Brand Names and Availability

Nexplanon: United States, Canada, Europe, Australia (FDA/EMA approved)
Implanon NXT: Australia, New Zealand, South Africa
Jadelle: Two-rod system available in 40+ countries, particularly developing nations
Sino-implant (II): Two-rod system used in China and other Asian markets

Pharmacology and Mechanism of Action

Etonogestrel: Third-Generation Progestin

Etonogestrel, the active metabolite of desogestrel, represents a highly potent synthetic progestin with unique pharmacological properties optimized for sustained release contraception.

Molecular Structure and Receptor Binding

Etonogestrel exhibits high affinity for progesterone receptors (150% relative to progesterone) with minimal cross-reactivity to androgen (15%), estrogen (0.1%), or mineralocorticoid receptors. This selectivity profile reduces androgenic side effects while providing potent contraceptive efficacy.

The elimination half-life of etonogestrel averages 25 hours, but the sustained-release implant maintains effective contraceptive levels for over three years. Plasma concentrations peak within 8 hours of insertion and remain above the contraceptive threshold (90 pg/mL) throughout the approved duration.

Triple Mechanism of Contraceptive Action

Like other progestin-only methods, contraceptive implants prevent pregnancy through multiple overlapping mechanisms that create redundant barriers to conception.

Primary Mechanisms of Action

Ovulation Suppression: Etonogestrel suppresses luteinizing hormone (LH) surges in 45-75% of cycles during the first two years, declining to 25-30% in the third year as hormone levels decrease
Cervical Mucus Changes: Progestin dramatically increases cervical mucus viscosity and reduces sperm penetrability by 99% within 24 hours of insertion
Endometrial Effects: Continuous progestin exposure causes endometrial atrophy and disrupts the normal secretory pattern, making implantation unlikely even if fertilization occurs

Pharmacokinetic Profile and Hormone Levels

Understanding etonogestrel pharmacokinetics helps explain both the contraceptive efficacy timeline and the pattern of side effects experienced by users.

Serum etonogestrel concentrations follow a predictable pattern: rapid rise to 816 pg/mL within 8 hours, plateau at 473 pg/mL during months 1-6, gradual decline to 156 pg/mL by year 3, with levels becoming undetectable within one week of removal.

Factors Affecting Hormone Levels

Body weight significantly influences etonogestrel pharmacokinetics, with women weighing >70kg showing 20-30% lower serum concentrations. Despite these differences, contraceptive efficacy remains >99% across all weight categories, though earlier replacement may be considered for women >90kg approaching the third year.

Insertion Procedure and Clinical Considerations

Pre-Insertion Assessment

Successful implant use begins with comprehensive medical screening to identify contraindications and optimize timing for insertion procedures.

Medical Eligibility Screening

Contraindications: Active thrombophlebitis, liver tumors, undiagnosed vaginal bleeding, known/suspected pregnancy, active liver disease, breast cancer
Relative Contraindications: History of ectopic pregnancy, diabetes with vascular complications, migraine with aura, severe depression
Drug Interactions: Enzyme-inducing medications (rifampin, phenytoin, carbamazepine, St. John's wort) may reduce efficacy

Insertion Technique and Timing

Proper insertion technique is critical for both contraceptive efficacy and minimizing complications, particularly avoiding deep placement that complicates future removal.

Optimal Insertion Timing

Menstruating women: Days 1-5 of menstrual cycle (no additional contraception needed)
Switching from pills: Within 7 days of last active pill
Postpartum non-breastfeeding: 21-28 days after delivery
Postpartum breastfeeding: After 4 weeks (minimal impact on lactation)
Post-abortion: Immediately or within 7 days

The insertion site is the non-dominant upper arm, 8-10cm above the medial epicondyle of the humerus. Proper subdermal placement (1-2mm below skin surface) ensures palpability while avoiding neurovascular structures and fascial planes that complicate removal.

Insertion Complications and Management

While insertion complications are rare (<0.5%), proper recognition and management are essential for optimal patient outcomes.

Immediate Insertion Complications

Nerve injury: Occurs in <0.1% of insertions, typically affecting the ulnar or median nerve if placement is too medial or deep
Vascular injury: Extremely rare but can cause significant hematoma formation
Deep insertion: Into muscle or fascia, significantly complicating future removal procedures
Expulsion: Occurs in 0.05% of cases, usually within the first year due to shallow placement

Studies of 11,000+ insertions show that 95% of complications relate to improper insertion technique rather than device failure. Comprehensive provider training reduces complication rates by 75% compared to untrained inserters.

Comprehensive Side Effects Profile

Menstrual Pattern Changes: The Most Common Effects

Menstrual irregularities represent the most frequent and significant side effect of contraceptive implants, affecting over 80% of users and causing the majority of early discontinuations.

Bleeding Pattern Classifications

Amenorrhea: Experienced by 22-33% of users, defined as no bleeding for 90+ days
Infrequent bleeding: Affects 35-42% of users, with bleeding episodes separated by >35 days
Frequent bleeding: Occurs in 7-17% of users, with bleeding episodes <21 days apart
Prolonged bleeding: Episodes lasting >14 days, experienced by 18-25% of users

Detailed bleeding diaries from 942 Nexplanon users reveal that bleeding patterns established in the first 3 months generally predict long-term patterns. Women experiencing amenorrhea in months 1-3 have an 85% likelihood of continued amenorrhea, while those with frequent bleeding initially show 60% improvement by year 2.

Neurological and Psychological Symptoms

Hormonal contraceptives can significantly impact neurological function and mood, with implant users reporting diverse neuropsychiatric symptoms that require careful monitoring.

Headache and Migraine Effects

Headaches affect 15-25% of implant users, with tension-type headaches being most common. Women with pre-existing migraines may experience pattern changes, with 30% reporting improvement, 40% no change, and 30% worsening. Migraine with aura development during implant use requires immediate evaluation and possible removal.

Depression and Anxiety Prevalence

Major depression: Reported by 22.6% of users (1,102 out of 4,867 reviews), with mood changes affecting 34% of participants in clinical studies
Panic disorder: Documented in case studies with symptoms including trembling, sweating, palpitations, and fear of death
Anxiety disorders: Users report daily panic attacks, intrusive thoughts, and severe social withdrawal
Suicidal ideation: Multiple case reports document severe cases requiring immediate psychiatric intervention

Analysis of 900 enrolled participants found that women using etonogestrel-only contraceptives had the second-highest rates of antidepressant use among all hormonal contraceptive formulations. Individual serum etonogestrel concentrations showed no correlation with mood symptoms, suggesting other personal factors influence susceptibility.
Metabolic and Weight-Related Symptoms

Weight gain concerns represent a primary reason for implant refusal and discontinuation, though scientific evidence suggests modest effects compared to user perceptions.

Weight Change Patterns

Controlled studies demonstrate average weight gain of 1.3-2.1 kg over three years of implant use, similar to age-matched controls not using hormonal contraception. However, 25% of users gain >5kg, while 15% lose >2kg, indicating significant individual variation in metabolic responses.

Metabolic studies show that etonogestrel has minimal impact on glucose metabolism, with HbA1c changes <0.1% in non-diabetic users. Lipid effects are generally favorable, with 5-10% increases in HDL cholesterol and minimal changes in LDL or triglycerides.

Dermatological Symptoms and Skin Changes

Skin-related side effects vary widely among implant users, reflecting individual sensitivity to progestin effects and baseline androgen levels.

Acne and Hair Changes

Acne: Affects 10-15% of users, typically mild-moderate severity. Pre-existing acne may worsen in 30% of cases but improves in 25%, with remaining users showing no change
Hirsutism: Excessive hair growth occurs in 2-5% of users, primarily affecting face, chest, and abdomen
Hair loss: Androgenetic alopecia patterns develop in 1-3% of users, usually reversible after removal
Insertion site effects: Local bruising (15%), pain (8%), and keloid formation (0.5%)

Gastrointestinal and Systemic Symptoms

Systemic effects of sustained progestin exposure can affect multiple organ systems, though most symptoms are mild and self-limiting.

Nausea affects 5-10% of implant users, typically occurring in the first 2-3 months as serum levels stabilize. Breast tenderness occurs in 8-12% of users, usually cyclical and resolving within 6 months. Abdominal pain is reported by 4-7% of users, though causality with the implant often remains unclear.

Bone Density and Cardiovascular Effects

Long-term health effects of sustained progestin exposure require ongoing monitoring, particularly regarding bone metabolism and cardiovascular risk profiles.

Bone Health Considerations

Unlike depot medroxyprogesterone acetate, contraceptive implants show minimal impact on bone density. Studies demonstrate <2% decrease in spine BMD over three years, with complete recovery within 12 months of removal. The low-dose continuous exposure appears insufficient to significantly suppress estrogen production needed for bone health.

Cardiovascular risk assessment studies involving >15,000 implant users show no increased risk of venous thromboembolism, myocardial infarction, or stroke compared to non-users. The progestin-only formulation avoids estrogen-related clotting risks associated with combination contraceptives.

Managing Side Effects and Patient Counseling

Bleeding Management Strategies

Effective management of menstrual irregularities can significantly improve implant continuation rates and user satisfaction.

Evidence-Based Bleeding Interventions

Expectant management: Counseling that patterns often improve after 6-12 months
NSAIDs: Ibuprofen 800mg TID for 5 days can reduce bleeding duration by 40-60%
Estrogen supplementation: 20-35μg ethinyl estradiol for 10-20 days for persistent bleeding
Tranexamic acid: 1g TID for heavy bleeding episodes (off-label use)

Mood and Psychological Support

Recognizing and addressing mood changes requires proactive screening and individualized management approaches.

Depression Screening and Management

Regular mood assessment using validated screening tools (PHQ-9, GAD-7) helps identify emerging depression or anxiety. Women with pre-existing mood disorders require more frequent monitoring, while those developing significant symptoms may benefit from concurrent antidepressant therapy or implant removal depending on severity and temporal relationship.

Weight Management Counseling

Addressing weight concerns requires evidence-based counseling that acknowledges individual variation while providing realistic expectations.

Effective weight counseling emphasizes that most users experience modest weight changes similar to natural weight fluctuations. Those experiencing significant weight gain (>5kg) should be evaluated for other contributing factors including dietary changes, decreased physical activity, or concurrent medications affecting metabolism.

Removal Procedures and Post-Removal Effects

Standard Removal Technique

Proper removal technique minimizes patient discomfort while ensuring complete implant extraction without fragmentation or retained portions.

Removal Procedure Steps

Localization: Palpate proximal end and mark skin overlying implant
Anesthesia: 2-3mL lidocaine injection under and around implant
Incision: 2-3mm longitudinal incision over proximal tip
Dissection: Blunt dissection to expose implant tip
Extraction: Grasp tip with forceps and extract intact rod

Standard removal procedures require an average of 3.5 minutes when performed by trained providers. Complications occur in <2% of removals, most commonly incomplete removal requiring referral for surgical extraction under ultrasound or fluoroscopic guidance.

Difficult Removal Situations

Non-palpable or deeply placed implants require specialized techniques and may necessitate referral to experienced providers or specialists.

Non-Palpable Implant Management

When implants cannot be palpated, ultrasound localization is the first-line approach, successful in 85-90% of cases. For implants visible on imaging but not accessible via standard techniques, surgical removal under direct visualization may be necessary. Never attempt removal without confirming implant location, as unsuccessful procedures increase complication risks.

Return to Fertility After Removal

Contraceptive implants have minimal impact on long-term fertility, with rapid return of ovulation and pregnancy potential following removal.

Etonogestrel becomes undetectable within one week of removal, with ovulation resuming within 7-14 days in most women. Pregnancy rates in the first year after removal are identical to age-matched controls, confirming that implants do not impair future fertility.

Special Populations and Clinical Considerations

Adolescent Users

Contraceptive implants offer particular advantages for adolescent users, providing highly effective contraception without daily adherence requirements.

Adolescent-Specific Benefits and Considerations

Studies in 13-18 year olds demonstrate 99.5% contraceptive efficacy with high satisfaction rates (82% would recommend to friends). Bone density effects are minimal in this age group, while the forgettable nature of implants addresses adherence challenges common with daily pills. However, bleeding irregularities may be more problematic for adolescents, requiring enhanced counseling and support.

Postpartum and Breastfeeding Women

Contraceptive implants provide ideal postpartum contraception with minimal impact on lactation and extended pregnancy prevention.

Studies of immediate postpartum insertion (within 48 hours of delivery) show no adverse effects on milk production or infant growth parameters. Etonogestrel transfer to breast milk is minimal (<1% of maternal dose), with no demonstrated effects on infant development or growth patterns.

Women with Medical Comorbidities

Many medical conditions that contraindicate estrogen-containing methods are compatible with progestin-only implants.

Medical Eligibility for High-Risk Conditions

Hypertension: No blood pressure elevation with progestin-only methods
Diabetes: Minimal glucose metabolism effects, suitable for most diabetic women
Migraine: Safe for migraine without aura; migraine with aura requires individualized assessment
Thrombophilia: No increased VTE risk, making implants preferred for women with clotting disorders

Global Health Impact and Access

Public Health Benefits

Long-acting reversible contraceptives like implants provide significant public health benefits through pregnancy prevention and reduced healthcare costs.

Economic analyses demonstrate that every dollar spent on contraceptive implant programs saves $7-12 in pregnancy-related healthcare costs. The high efficacy and long duration make implants particularly cost-effective for publicly funded family planning programs serving high-risk populations.

Barriers to Access and Uptake

Despite proven benefits, implant uptake remains limited by multiple barriers including cost, provider training, and patient knowledge gaps.

US data shows that implant use remains <2% among contraceptive users, far below public health targets. Primary barriers include high upfront costs ($800-1200), limited provider training for insertion/removal, and patient concerns about side effects and removal procedures.

Global Expansion and Adaptation

International programs demonstrate successful implant scale-up when combined with comprehensive training and support systems.

Success Stories and Lessons Learned

Rwanda's national implant program achieved 27% contraceptive prevalence through systematic provider training and community education. Ethiopia's Health Extension Program trained 34,000 rural health workers in implant services, increasing rural access by 400%. These programs demonstrate that successful implant introduction requires sustained investment in training, supply chains, and patient education.

Future Developments and Innovation

Next-Generation Implant Technologies

Research continues developing improved implant formulations addressing current limitations while enhancing user experience and provider convenience.

Biodegradable implants eliminating removal procedures are in development, using polymer matrices that completely dissolve after hormone depletion. Additionally, multi-drug implants combining contraception with other medications (HIV prevention, iron supplementation) could address multiple health needs simultaneously.

Personalized Contraceptive Selection

Advances in pharmacogenomics may enable personalized implant selection based on individual metabolism patterns and side effect susceptibility.

Genetic Markers and Hormonal Response

Research into CYP3A4 polymorphisms affecting etonogestrel metabolism could identify women requiring dose adjustments or alternative methods. Similarly, genetic markers for depression susceptibility might help predict which users are at highest risk for mood-related side effects.

Evidence-Based Patient Counseling

Pre-Insertion Counseling Elements

Comprehensive counseling improves implant satisfaction and continuation rates by establishing appropriate expectations and management strategies.

Essential Counseling Topics

Efficacy: >99.95% effective, more reliable than sterilization
Duration: Three years of protection with immediate reversibility
Bleeding changes: 80% experience pattern changes, many improve over time
Other side effects: Weight changes typically modest, mood effects individual
Insertion/removal: Minor procedures with local anesthesia

Follow-Up Care and Monitoring

Structured follow-up protocols optimize implant outcomes while identifying users who might benefit from alternative methods.

Recommended Follow-Up Schedule

3 months: Assessment of bleeding patterns, side effects, and satisfaction
12 months: Annual health maintenance and side effect evaluation
24 months: Mid-term assessment and counseling about replacement timing
36 months: Removal or replacement discussion and procedure scheduling

Clinical Decision-Making Framework

Ideal Candidates for Implant Use

Identifying optimal implant candidates improves success rates and user satisfaction while maximizing public health benefits.

Characteristics of Ideal Implant Users

Motivation: Desire for long-term, highly effective contraception
Lifestyle: Difficulty with daily pill adherence or frequent intercourse
Medical: Contraindications to estrogen-containing methods
Reproductive goals: Want to delay pregnancy for 2+ years
Acceptance: Comfortable with menstrual pattern changes and minor procedures

When to Consider Alternative Methods

Recognizing when implants may not be optimal helps providers guide patients toward more suitable contraceptive options.

Women with strong preferences for regular monthly periods, history of depression requiring medication, or concerns about weight gain may be better served by alternative methods. Additionally, those planning pregnancy within 1-2 years might prefer shorter-acting reversible methods that don't require removal procedures.

Research Frontiers and Future Directions

Current Research Priorities

Contemporary implant research focuses on developing formulations with improved bleeding profiles, biodegradable systems eliminating removal procedures, and combination devices addressing multiple health needs simultaneously. The ultimate goal remains providing women with long-acting contraceptive options that maximize effectiveness while minimizing side effects and procedural requirements.

Understanding contraceptive implants requires appreciation of their sophisticated drug delivery technology, diverse physiological effects, and individual variation in responses. The evolution from early multi-rod systems to current single-rod technology demonstrates the power of iterative improvement in medical device development.

The most critical aspect of implant provision is ensuring comprehensive counseling that prepares users for likely experiences while providing ongoing support for side effect management. Success requires matching patient preferences and medical profiles with appropriate contraceptive technologies.

Whether considering Nexplanon in developed healthcare systems or alternative implant technologies in resource-limited settings, contraceptive implants represent a revolutionary advance in reproductive healthcare. The combination of exceptional efficacy, long duration, and rapid reversibility makes implants uniquely valuable for women seeking reliable pregnancy prevention without daily intervention requirements.

Scientific References

1. Darney P, Patel A, Rosen K, Shapiro LS, Kaunitz AM. Safety and efficacy of a single-rod etonogestrel implant (Implanon): results from 11 international clinical trials. *Fertility and Sterility*. 2009;91(5):1646-1653.

2. Mansour D, Korver T, Marintcheva-Petrova M, Fraser IS. The effects of Implanon on menstrual bleeding patterns. *European Journal of Contraception & Reproductive Health Care*. 2008;13(sup1):13-28.

3. Zieman M, Guillebaud J, Weisberg E, Shangold GA, Fisher AC, Creasy GW. Contraceptive efficacy and cycle control with the Ortho Evra/Evra transdermal system: the analysis of pooled data. *Fertility and Sterility*. 2002;77(2 Suppl 2):S13-18.

4. Berenson AB, Odom SD, Breitkopf CR, Rahman M. Physiologic and psychologic factors associated with perceived weight gain in users of the contraceptive implant. *Obstetrics & Gynecology*. 2014;124(4):697-704.

5. Brache V, Faundes A, Alvarez F, Cochon L. Nonmenstrual adverse events during use of implantable contraceptives for women: data from clinical trials. *Contraception*. 2002;65(1):63-74.

6. Funk S, Miller MM, Mishell DR Jr, et al. Safety and efficacy of Implanon, a single-rod implantable contraceptive containing etonogestrel. *Contraception*. 2005;71(5):319-326.

7. Mascarenhas MN, Flaxman SR, Boerma T, Vanderpoel S, Stevens GA. National, regional, and global trends in infertility prevalence since 1990: a systematic analysis of 277 health surveys. *PLoS Medicine*. 2012;9(12):e1001356.

8. Reed S, Do Minh T, Lange HL, et al. Real-world efficacy of a progestogen contraceptive implant over 4 years in a US clinical setting. *Contraception*. 2018;97(4):337-340.

9. Organon USA Inc. Nexplanon (etonogestrel implant) Prescribing Information. 2019. Available at: https://www.merck.com/product/usa/pi_circulars/n/nexplanon/nexplanon_pi.pdf

10. World Health Organization. Selected practice recommendations for contraceptive use. 3rd ed. Geneva: World Health Organization; 2016.

11. Faculty of Sexual and Reproductive Healthcare. Progestogen-only Implants. FSRH Clinical Guidance. 2021. Available at: https://www.fsrh.org/standards-and-guidance/documents/ceuguidanceprogestogenonlyimplants/

12. Centers for Disease Control and Prevention. U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. *MMWR Recommendations and Reports*. 2016;65(3):1-103.

13. Stoddard A, McNicholas C, Peipert JF. Efficacy and safety of long-acting reversible contraception. *Drugs*. 2011;71(8):969-980.

14. Blumenthal PD, Gemzell-Danielsson K, Marintcheva-Petrova M. Tolerability and clinical safety of Implanon. *European Journal of Contraception & Reproductive Health Care*. 2008;13(sup1):29-36.

15. Graesslin O, Korver T. The contraceptive efficacy of Implanon: a review of clinical trials and marketing experience. *European Journal of Contraception & Reproductive Health Care*. 2008;13(sup1):4-12.

16. Mommers E, Blum GF, Gent TG, Peters KP, Sørdal TS, Marintcheva-Petrova M. Nexplanon, a radiopaque etonogestrel implant in combination with a next-generation applicator: 3-year results of a noncomparative multicenter trial. *American Journal of Obstetrics and Gynecology*. 2012;207(5):388.e1-6.

17. Westhoff CL, Torgal AH, Mayeda ER, et al. Predictors of noncompliance in an oral contraceptive clinical trial. *Contraception*. 2007;75(5):367-370.

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