What birth control medications are available for an 18-year-old female with no past medical history?

Available Birth Control Medications for an 18-Year-Old Female with No Past Medical History

For an 18-year-old female with no medical contraindications, long-acting reversible contraception (LARC)—specifically the levonorgestrel IUD or etonogestrel implant—should be offered as first-line options due to superior effectiveness (<1% failure rate) and high continuation rates, combined with mandatory condom use for STI protection. 1

First-Line Recommendations: Long-Acting Reversible Contraception (LARC)

Levonorgestrel Intrauterine Device (LNG-IUD)

• Failure rate <1% per year with continuation rates ≥75% at 1 year 1
• Provides excellent menstrual suppression without estrogen exposure 1
• Particularly beneficial for heavy menstrual bleeding or dysmenorrhea 1
• Category 2 for nulliparous women aged ≥20 years (advantages generally outweigh risks) 2

Etonogestrel Implant

• Failure rate <1% per year 1
• Single-rod subdermal device providing 3 years of contraception 3
• Category 1 for women aged 18-45 years (no restrictions for use) 2
• May reduce dysmenorrhea symptoms 3

Combined Hormonal Contraceptives

Combined Oral Contraceptives (COCs)

• Start with monophasic pills containing 30-35 μg ethinyl estradiol plus levonorgestrel or norgestimate 4
• Category 1 for women aged 18-39 years who do not smoke 2
• Use "quick start" method: begin same day as visit without requiring pelvic examination 1, 4
• Backup contraception (condoms) required for first 7 days 1, 4
• Typical use failure rate: 9% 2
• Perfect use failure rate: <3% 5

Non-contraceptive benefits include: 1

• Long-term protection against endometrial and ovarian cancers (>4 years use)
• Decreased menstrual cramping and blood loss
• Improvement in acne
• Reduced risk of iron-deficiency anemia

Contraceptive Vaginal Ring (NuvaRing)

• Insert vaginally for 3 weeks, remove for 1 week 2
• Same eligibility criteria and efficacy as COCs 2
• Can be used for extended cycles (up to 35 days per ring, replaced monthly) 2
• Simplest regimen with comparable risks and benefits to other combined methods 2

Transdermal Contraceptive Patch (Ortho Evra)

• Apply one patch weekly for 3 weeks, followed by 1 week off 2
• Typical use failure rate: 9% 2
• Warning: 1.6 times higher estrogen exposure than low-dose COCs with potential increased VTE risk 2
• Slightly higher pregnancy risk in women >198 pounds (0.9% vs 0.3%) 2

Progestin-Only Options

Progestin-Only Pills (POPs/"Mini-Pills")

• Category 1 for women aged 18-45 years 2
• Requires very stringent adherence (same time daily) 2
• Higher failure rate than combined methods due to adherence requirements 2
• Appropriate for patients with contraindications to estrogen 2

Depot Medroxyprogesterone Acetate (DMPA/Depo-Provera)

• Category 2 for women aged 18-45 years (advantages generally outweigh risks) 2
• Injectable contraception given every 3 months 3
• Particularly useful for women with sickle cell disease (reduces painful crises) or epilepsy (no interaction with antiepileptics) 3

Copper Intrauterine Device (Cu-IUD)

• Category 2 for nulliparous women aged ≥20 years 2
• Non-hormonal option providing up to 10 years of contraception 2
• Also serves as emergency contraception if inserted within 5 days of unprotected intercourse 2

Emergency Contraception (Advance Prescription Recommended)

Levonorgestrel 1.5 mg (Plan B One-Step)

• Available over-the-counter for all women of childbearing potential 1, 6
• Take within 72 hours of unprotected intercourse; effectiveness up to 85% 2, 6
• Sooner administration = better efficacy 6
• Single tablet, one-time dose 6

Ulipristal Acetate

• May have increased effectiveness over levonorgestrel at end of 5-day window 1
• More effective in women weighing >165 pounds 2, 1
• Pregnancy category X 1

Mandatory Dual Protection Strategy

All sexually active adolescents must use condoms regardless of other contraceptive method chosen 1

• Male latex condoms: 2% failure rate with perfect use, 18% with typical use 1
• Only method that protects against STIs including HIV 2, 1
• Correct and consistent use reduces STI and HIV transmission risk 2

Critical Safety Considerations

Absolute contraindications to combined hormonal contraceptives (COCs, patch, ring): 4

• Smoking ≥15 cigarettes/day in women ≥35 years (Category 4) 2
• Migraines with aura at any age (Category 4) 2
• History of venous thromboembolism, stroke, or cardiovascular disease 3
• Severe uncontrolled hypertension 4
• Active liver disease or liver tumors 4

Important counseling points: 1

• No contraceptive method except condoms protects against STIs
• Discuss typical-use versus perfect-use failure rates
• VTE risk increases 3-4 fold with COCs (from 1 per 10,000 to 4 per 10,000 woman-years in adolescents) 4
• COCs are much safer than pregnancy and have no negative effect on long-term fertility 4, 7

Follow-Up Protocol

• Schedule routine follow-up 1-3 months after initiating any hormonal method 4
• Address persistent adverse effects or adherence issues 4
• If amenorrhea occurs at time of first missed period, consider pregnancy 8
• Rule out pregnancy if amenorrhea persists for two or more consecutive cycles 8