Effect of t of the Etonogestrel Releasing Implant on Infant Growth and Development

Inclusion Criteria: * Women who desire to use the ENG implant as a contraceptive method and desire to breastfeed her newborn for ate least 3 months; * With no contraindication to breastfeeding, whose newborn is healthy, without malformations, born at term (gestational age ≥ 37 weeks), with appropriate weight for gestational age and with normal sucking ability Exclusion Criteria: * Tobacco smokers, drug addicts or alcoholics; * Women with educational levels lower than 5 years; * Women with clinical conditions considered category 3 and 4 for implant use by the WHO; * Women with histories of psychiatric illness; * Women using medications that could alter the concentration of ENG, * Women with known allergies to the local anesthetic lidocaine (used to place the implant); * Women who wanted to keep their cyclic menstrual bleeding