A 35-year-old woman from urban Delhi attends the family planning clinic 3 weeks after vaginal delivery of her third child. She is exclusively breastfeeding and has no menstrual bleeding since delivery. Her partner works abroad and returns home once every 6 months. She desires a contraceptive method that requires minimal compliance and can be initiated immediately. She has no medical contraindications. Based on epidemiological evidence of contraceptive failure rates in India, which method would be most appropriate for her situation?