What are the suitable contraceptive options for a 16-year-old female with obesity (Body Mass Index (BMI) of 35) and increased risk of sexually transmitted infections (STIs)?

Contraceptive Options for a 16-Year-Old with BMI 35 and STI Risk

All contraceptive methods are medically appropriate for this adolescent with obesity, but long-acting reversible contraceptives (LARCs)—specifically the etonogestrel implant and levonorgestrel IUD—are the most effective options, and condoms must be used consistently with any method chosen for STI protection. 1, 2

Key Principle: Dual Protection Strategy

• No hormonal or intrauterine contraceptive protects against STIs—condoms must be used consistently and correctly alongside any contraceptive method for STI prevention 1
• The correct and consistent use of male latex condoms reduces the risk for STI and HIV transmission 1

Most Effective Options: Long-Acting Reversible Contraceptives (LARCs)

Etonogestrel Implant (First-Line Recommendation)

• The contraceptive implant has the lowest failure rate (0.05%) of all contraceptive methods and is ideal for adolescents who prefer a method without scheduled adherence 1, 2
• Obesity (BMI ≥30) is Category 1 (no restriction) for implant use—effectiveness is not reduced 1
• No examination required before insertion; can be inserted anytime during menstrual cycle 1
• If inserted >5 days after menses started, use backup contraception (condoms or abstinence) for 7 days 1
• Common reason for discontinuation is unpredictable bleeding or spotting, but this does not indicate reduced effectiveness 1
• Approved for 3 years of use 1

Levonorgestrel IUD (Excellent Alternative)

• Failure rate <1% and safe for nulliparous adolescents—past concerns about infertility and infection risk are not supported by evidence 1, 2, 3
• Obesity is Category 1 (no restriction) for LNG-IUD use 1
• Reduces menstrual bleeding, which can be beneficial 2
• Requires bimanual examination and cervical inspection before insertion 1
• STI screening can be performed at the time of IUD insertion and should not delay placement unless the patient has current purulent cervicitis or confirmed gonorrhea/chlamydia infection 1, 4
• If inserted >7 days after menses started, use backup contraception for 7 days 1
• Available in two formulations: 52 mg (approved for 5 years) and 13.5 mg (approved for 3 years) 1

Critical caveat: The risk of pelvic infection with IUDs occurs only during the first 21 days after insertion; beyond this period, IUDs do not increase rates of STIs or pelvic inflammatory disease 1, 4

Copper IUD

• Highly effective (failure rate <1%) and provides immediate contraception without backup needed 1, 2
• Obesity is Category 1 (no restriction) 1
• Can be inserted anytime; no backup contraception required 1
• Approved for 10 years 1
• Same STI screening considerations as LNG-IUD 1, 4
• Can also serve as emergency contraception if needed within 5 days of unprotected intercourse 1

Depot Medroxyprogesterone Acetate (DMPA) Injection

• Failure rate <1% with typical use 1
• Category 2 (advantages generally outweigh risks) for adolescents aged <18 years due to concerns about bone mineral density, though BMD recovers after discontinuation 1
• Obesity is Category 1 (no restriction) 1
• No examination required before initiation 1
• If given >7 days after menses started, use backup contraception for 7 days 1
• Given every 3 months 1

Combined Hormonal Contraceptives (Pills, Patch, Ring)

• Obesity is Category 2 (advantages generally outweigh risks) for combined hormonal contraceptives 1
• Blood pressure measurement required before initiation 1
• If started >5 days after menses started, use backup contraception for 7 days 1
• Requires daily adherence (pills) or weekly/monthly adherence (patch/ring), which may be challenging for adolescents 1

Progestin-Only Pills (POPs)

• Obesity is Category 1 (no restriction) 1
• No examination required before initiation 1
• Requires strict daily adherence—if started >5 days after menses (norethindrone/norgestrel) or >1 day after menses (drospirenone), backup contraception needed for 2-7 days depending on formulation 1
• Less forgiving of missed pills compared to combined hormonal contraceptives 1

Emergency Contraception Considerations

• Ulipristal acetate may be more effective than levonorgestrel in women who are overweight or obese 2
• Copper IUD is the most effective emergency contraception method 1
• Emergency contraception use has no restrictions (Category 1) regardless of medical conditions 1

Critical Clinical Pitfalls

1. Do not delay IUD insertion for STI screening results unless the patient has visible purulent cervicitis or a partner with known gonorrhea—screen at the time of insertion and treat if positive without removing the device 1, 4

2. Do not assume obesity reduces contraceptive effectiveness—weight and BMI measurements are not needed to determine medical eligibility as all methods can be used among patients with obesity 1, 2

3. Do not forget dual protection counseling—emphasize that no contraceptive method except condoms protects against STIs 1

4. Age <20 years is Category 2 for IUDs due to concerns about expulsion and STI risk from sexual behavior, but these are not contraindications 1