What are the long-term side effects of contraception?

Long-Term Side Effects of Contraception

Most contraceptive methods have minimal serious long-term side effects, with the notable exception that combined oral contraceptives (COCs) increase venous thromboembolism risk from 2-10 to 7-10 events per 10,000 women-years, and depot medroxyprogesterone acetate (DMPA) causes reversible bone mineral density loss. 1

Hormonal Contraceptives

Combined Oral Contraceptives (COCs)

Cardiovascular Effects:

• COCs increase venous thromboembolism risk, particularly in women with obesity where the risk is further elevated 2, 3
• The risk is dose-dependent, with lower estrogen formulations (≤35 μg ethinyl estradiol) carrying reduced risk compared to higher doses 3
• The absolute risk remains low in adolescents despite the relative increase 2

Cancer Risk:

• Use for more than 4 years provides significant protection against endometrial and ovarian cancers 2
• No increased risk of breast cancer has been demonstrated in observational data 2
• No increased risk of infertility with COC use 2

Metabolic Effects:

• Minimal impact on glucose tolerance in most users 4
• Women with diabetes generally do not experience changes in insulin requirements 4
• Occasional effects on lipid metabolism with decreased HDL2 and apolipoprotein A-I and A-II 4

Progestin-Only Methods

Depot Medroxyprogesterone Acetate (DMPA):

• Causes bone mineral density loss that is largely reversible after discontinuation 2, 5
• Initial bone density losses stabilize by 5 years, with return to pre-use levels upon stopping 2
• Most consistently associated with weight gain among all contraceptive methods 6
• Delayed return to fertility compared to other methods 2

Progestin-Only Pills:

• Androgenic side effects (acne, hirsutism, weight gain) occur rarely 4
• Small amounts pass into breast milk (1-6% of maternal plasma levels) with very rare adverse effects in infants 4

Implants:

• Changes in menstrual bleeding patterns are the most common side effect and primary reason for discontinuation 2
• Scant data on effects on bone mineral density 2
• No negative effect on long-term fertility 5

Intrauterine Devices (IUDs)

Copper IUD:

• No hormonal exposure, making it the most weight-neutral option 6
• Menstrual bleeding often heavier than in non-users, potentially with increased menstrual pain 7
• Approximately 6 pelvic infections per 1,000 woman-years, with slightly elevated risk in first 3 months after insertion 7
• Uterine perforation occurs in 0.6-16 per 1,000 insertions 7
• Expulsion rate of 5-10% within 5 years 7

Levonorgestrel IUD:

• Marked reduction in menstrual blood loss with amenorrhea in 35% of women after 2 years 7
• Hormonal side effects include headache, acne, breast tension, and functional ovarian cysts 7
• No increased risk of pelvic infection or complications in HIV-infected women compared to uninfected women 2

Special Populations

Post-Bariatric Surgery:

• COCs may be less reliable after malabsorptive procedures due to altered absorption 2, 3
• Postoperative complications (vomiting, diarrhea) can decrease oral contraceptive effectiveness 2
• Long-acting reversible contraception (LARC) methods remain unaffected by bariatric surgery and should be first-line 2

HIV-Infected Individuals:

• IUDs do not adversely affect HIV disease progression or increase transmission risk to partners 2
• Progestin-only injectables may or may not increase HIV transmission risk to partners; women should be counseled about this uncertainty 2
• Many antiretroviral agents interact with hormonal contraceptives, particularly efavirenz with implants 2

Common Pitfalls to Avoid

• Do not assume all hormonal methods cause weight gain: Only DMPA is consistently associated with significant weight gain; COCs and copper IUDs are weight-neutral 6
• Do not withhold IUDs from nulliparous women: The only issues are increased insertion pain and slightly higher expulsion rates, not contraindications 7
• Do not require extensive screening before contraceptive initiation: Cervical cytology, breast examination, and routine STI testing should not be prerequisites that create barriers to care 2
• Do not forget that barrier methods provide no protection against STIs: Dual method use (condom plus effective contraceptive) should be encouraged, especially in HIV-infected individuals 2