Recommended Birth Control Options for Obese Women
All contraceptive methods can be safely used by obese women (BMI ≥30 kg/m²), with intrauterine devices (IUDs) and implants being the most effective options regardless of body weight. 1
First-Line Recommendations for Obese Women
- Intrauterine Devices (IUDs): Both copper and levonorgestrel-releasing IUDs are classified as Category 1 (no restrictions) for obese women, with no reduction in effectiveness related to body weight 1
- Contraceptive Implants: The etonogestrel implant is classified as Category 1 for obese women with no evidence of reduced effectiveness 1
- Injectable Contraceptives: Depot medroxyprogesterone acetate (DMPA) is Category 1 for obese women with maintained effectiveness 1, 2
Second-Line Options
- Progestin-Only Pills (POPs): Classified as Category 1 for obese women with no restrictions on use 1, 3
- Combined Hormonal Contraceptives (CHCs): Classified as Category 2 (benefits generally outweigh risks) for obese women without additional cardiovascular risk factors 1, 3
Special Considerations for Obese Women
Combined Hormonal Contraceptives (Pills, Patch, Ring)
- Obese women using CHCs have an increased risk of venous thromboembolism (VTE) compared to non-users, though absolute risk remains small 3
- When obesity is combined with other cardiovascular risk factors (smoking, hypertension, etc.), CHCs become Category 3/4 (risks may outweigh benefits) 1, 3
- Blood pressure measurement is required before CHC initiation 1
Transdermal Patch
- Evidence suggests decreased effectiveness in women weighing >90 kg 3, 2
- Consider alternative methods for women above this weight threshold 2
Emergency Contraception
- Levonorgestrel emergency contraception may have reduced effectiveness in obese women 1, 4
- Ulipristal acetate or copper IUD are preferred emergency contraception options for obese women 1
Post-Bariatric Surgery
- For restrictive procedures (gastric banding, sleeve gastrectomy): all contraceptive methods remain Category 1 1, 3
- For malabsorptive procedures (gastric bypass): oral contraceptives are Category 3 (risks usually outweigh benefits) due to potential decreased absorption 1, 3
- IUDs and implants are preferred after malabsorptive bariatric procedures 3
Pre-Initiation Requirements
- Weight/BMI measurement: Not required for determining medical eligibility for any contraceptive method, as all methods can be used by obese women 1
- Blood pressure: Required only for combined hormonal contraceptives 1
- Bimanual examination and cervical inspection: Required only for IUD insertion 1
- STD screening: Not routinely required before contraceptive initiation unless indicated by risk factors 1
Common Pitfalls to Avoid
- Assuming decreased effectiveness of all hormonal methods in obese women - most methods maintain full effectiveness regardless of weight 1, 2
- Failing to consider the combined effect of obesity with other cardiovascular risk factors when prescribing CHCs 3
- Overlooking the potential reduced effectiveness of the transdermal patch in women >90 kg 3, 2
- Not considering the impact of bariatric surgery type on contraceptive absorption 3
Algorithm for Contraceptive Selection in Obese Women
- First assess for additional cardiovascular risk factors (smoking, hypertension, diabetes, dyslipidemia)
- If no additional risk factors: All methods are appropriate, with LARCs (IUDs, implants) being most effective
- If additional risk factors exist: Avoid CHCs; recommend IUDs, implants, DMPA, or POPs
- For women post-bariatric surgery: Choose based on procedure type (avoid oral methods after malabsorptive procedures)
- For women >90 kg: Consider avoiding the transdermal patch due to potential reduced effectiveness