OBJECTIVE: The long-lasting reversible contraceptives such as the etonogestrel implant represent an option for the reduction of unwanted pregnancies, especially among patients at risk for a short intergestational period. Our purpose was to determine the effect of etonogestrel-releasing contraceptive implant when inserted in the immediately post partum on anthropometric measures, blood pressure and hemoglobin during six weeks after delivery.DESIGN: Controlled, Randomized, Clinical Trial.MATERIALS AND METHODS: We selected 40 puerperae aged 18 to 35 years at the Low Risk Prenatal Care Program of the University Hospital of Ribeirao Preto, Sao Paulo (HC-FMRP), Brazil. The subjects were randomized into to two groups: one for treatment with etonogestrel-releasing implant (ETG) to be inserted 24 to 48 hours after delivery, the other not to use any contraceptive method until six weeks after delivery (control-group). We evaluated the blood pressure, weight, body mass index, hemoglobin and percentage of breast-feeding mother within 6 weeks after delivery. Paired Student t-test and unpaired Student t-test were used as appropriate.RESULTS: At the baseline evaluation, the groups have the similar age (ETG: 22.5± 2.5 years vs Control: 22.9 ±4.4 years, p=0.75), weight (ETG: 62.3 ± 9.4 Kg vs Controls: 65.2 ± 7.9 Kg, p=0.28), BMI (ETG: 24.1 ± 3.1 Kg/m2 vs Controls: 25.4 ± 2.1 Kg/m2, p=0.14), systolic and diastolic blood pressure and hemoglobin. The hemoglobin have raised, systolic and diastolic blood pressure and weight have reduced during six weeks within both groups, with no difference between the groups. However, the BMI was lower in ETG group than in controls after six weeks of delivery (ETG: 22.3 ± 2.9 Kg/m2 vs Controls: 24.4 ± 2.3 Kg/m2, p = 0.018). The percentage of breast-feeding women were similar between the groups in this period (ETG: 90% vs Contols: 85%, p = 1).CONCLUSIONS: The etonogestrel-releasing implant is associated with a reduction in BMI when inserted immediately post partum, with no change in hemoglobin, percentage of breast-feeding mothers, systolic and diastolic blood pressure when compared with no hormonal treatment in six weeks after delivery. This could be an interesting method for patients at risk for short intergestational period. OBJECTIVE: The long-lasting reversible contraceptives such as the etonogestrel implant represent an option for the reduction of unwanted pregnancies, especially among patients at risk for a short intergestational period. Our purpose was to determine the effect of etonogestrel-releasing contraceptive implant when inserted in the immediately post partum on anthropometric measures, blood pressure and hemoglobin during six weeks after delivery. DESIGN: Controlled, Randomized, Clinical Trial. MATERIALS AND METHODS: We selected 40 puerperae aged 18 to 35 years at the Low Risk Prenatal Care Program of the University Hospital of Ribeirao Preto, Sao Paulo (HC-FMRP), Brazil. The subjects were randomized into to two groups: one for treatment with etonogestrel-releasing implant (ETG) to be inserted 24 to 48 hours after delivery, the other not to use any contraceptive method until six weeks after delivery (control-group). We evaluated the blood pressure, weight, body mass index, hemoglobin and percentage of breast-feeding mother within 6 weeks after delivery. Paired Student t-test and unpaired Student t-test were used as appropriate. RESULTS: At the baseline evaluation, the groups have the similar age (ETG: 22.5± 2.5 years vs Control: 22.9 ±4.4 years, p=0.75), weight (ETG: 62.3 ± 9.4 Kg vs Controls: 65.2 ± 7.9 Kg, p=0.28), BMI (ETG: 24.1 ± 3.1 Kg/m2 vs Controls: 25.4 ± 2.1 Kg/m2, p=0.14), systolic and diastolic blood pressure and hemoglobin. The hemoglobin have raised, systolic and diastolic blood pressure and weight have reduced during six weeks within both groups, with no difference between the groups. However, the BMI was lower in ETG group than in controls after six weeks of delivery (ETG: 22.3 ± 2.9 Kg/m2 vs Controls: 24.4 ± 2.3 Kg/m2, p = 0.018). The percentage of breast-feeding women were similar between the groups in this period (ETG: 90% vs Contols: 85%, p = 1). CONCLUSIONS: The etonogestrel-releasing implant is associated with a reduction in BMI when inserted immediately post partum, with no change in hemoglobin, percentage of breast-feeding mothers, systolic and diastolic blood pressure when compared with no hormonal treatment in six weeks after delivery. This could be an interesting method for patients at risk for short intergestational period.