Is Etonogestrel safe while breastfeeding?

Effects on the breastfed infant

Forty-two women had an etonogestrel subcutaneous implant (Implanon) inserted between 28 and 56 days postpartum. Compared with the infants of 38 similar mothers who had a nonhormonal intrauterine device, no statistically significant difference was found in infant illnesses or growth rates between the groups, except for a statistically nonsignificant higher weight gain in the male infants, and respiratory conditions and skin disorders in the infants of women who received the implants.[ 6 ] Infants were followed up at 3 years of age; no differences in growth or psychomotor development were found.[ 11 ] A non-blinded, randomized study of exclusively breastfeeding women compared those who received an etonogestrel implant 24-48 hours after delivery (n = 20) to those who received a 150 mg depot medroxyprogesterone acetate injection at 6 weeks postpartum (n = 20). No difference in infant weight gain was noted between the two groups.[ 12 ] A randomized, prospective study compared the growth of infants of mothers who received an etonogestrel implant either within 48 hours (n = 50) of delivery or 6 weeks (n = 50) postpartum. Breastfeeding rates and growth of the infants were not significantly different between the groups over the first year of life.[ 13 ] A follow-up study found that infants had normal development up to 12 to 15 months.[ 14 ] The manufacturer reports a study in which 38 women had an etonogestrel implant inserted during the 4 th to 8 th week postpartum. Adverse reactions were not observed in breastfed infants exposed to etonogestrel through breast milk. A prospective, nonrandomized trial compared 4 contraceptives in 10 women each to assess their effect on milk production. One of the following were begun on day 42 postpartum as chosen by the mother: combined ethinyl estradiol 30 mcg plus levonorgestrel 150 mcg (Microvlar), etonogestrel implant (Implanon), levonorgestrel intrauterine system (Myrena), or a copper IUD (Optima). Milk intake was measured using deuter

Effects on milk supply

Forty-two women had an etonogestrel subcutaneous implant (Implanon) inserted between 28 and 56 days postpartum. Compared with 38 similar mothers who had a nonhormonal intrauterine device, no difference was found in milk volume, or in milk lactose, protein or fat content.[ 10 ] No difference was seen between the two groups in duration of lactation, averaging 421 days in the Implanon group and 423 days in the IUD group.[ 11 ] The manufacturer reports a study in which 38 women had an etonogestrel implant inserted during the 4 th to 8 th week postpartum. No adverse effects on the production or quality of breast milk were detected. A non-blinded, randomized study of exclusively breastfeeding women compared those who received an etonogestrel implant 24 to 48 hours after delivery (n = 20) to those who received a 150 mg depot medroxyprogesterone acetate injection at 6 weeks postpartum (n = 20). The rates of exclusive breastfeeding were similar between the groups at 6 and 12 weeks postpartum.[ 12 ] A randomized, controlled study compared etonogestrel implant insertion at 1 to 3 days postpartum (n = 35) to insertion at 4 to 8 weeks postpartum (n = 34). Several outcome parameters were measured: time to lactogenesis II, prevalence of lactation failure, use of formula supplementation and milk composition at 6 weeks postpartum. No differences were found in any of the outcomes between the two groups.[ 17 ] A woman was breastfeeding a newborn successfully with good infant growth. On day 39 postpartum, an etonogestrel implant (Nexplanon) was inserted. By day 70 postpartum, the mother reported a decrease in milk supply, and her infant had lost weight, going from the 44th percentile to the 6th percentile for growth. Five weeks later, the mother had transitioned completely to formula feeding. The authors requested reports on etonogestrel from the FDA and found a similar case of loss of milk supply. From a review of 4 published studies, the authors estimated that there is about a 0.9% (

Levels in milk

Maternal Levels. Forty-two women had an etonogestrel subcutaneous implant inserted implant inserted between 28 and 56 days postpartum. Breastmilk samples were obtained at 1, 2 and 4 months after insertion. The average breastmilk concentration of etonogestrel was 178 ng/L at 1 month (n = 41), 153 ng/L at 2 months (n = 38), and 131 ng/L at 4 months (n = 38) after insertion. The authors calculated that the infants would receive an average of 19.9 ng/kg daily at 1 month, 15.1 ng/kg daily at 2 months and 10.5 ng/kg daily at 4 months after insertion. The decreasing doses were caused by both a reduced quantity in milk and a lower breastmilk intake as time passed.[ 10 ] The manufacturer reports a study in which 38 women had an etonogestrel implant inserted during the 4 th to 8 th week postpartum. Based on the findings of this study, during the first months after insertion of etonogestrel, when maternal blood levels of etonogestrel are highest, about 100 ng of etonogestrel may be ingested by the child per day based on an average daily milk ingestion of 658 mL. Based on daily milk ingestion of 150 mL/kg, the mean daily infant etonogestrel dose one month after insertion of an etonogestrel implant is about 2.2% of the weight-adjusted maternal daily dose. Infant Levels. Relevant published information was not found as of the revision date.

Alternatives LactMed lists

• Intrauterine Copper Contraceptive
• Oral Levonorgestrel
• Intrauterine Levonorgestrel
• Levonorgestrel Implant
• Medroxyprogesterone Acetate
• Norethindrone
• Progesterone