Is Oral Levonorgestrel safe while breastfeeding?

Effects on the breastfed infant

One study found serum thyroid stimulating hormone levels to be lower in the infants exposed to levonorgestrel than in control infants.[ 17 ] A nonrandomized trial compared 250 breastfed infants whose mothers received 30 mcg daily of oral levonorgestrel initiated 7 days postpartum to 250 infants whose mothers received nonhormonal contraception. No differences in height and weight gain were seen during the 9-month study period between the 2 groups.[ 18 ] Multicenter, nonrandomized studies followed infants whose mothers received levonorgestrel contraception during breastfeeding, either as oral tablets of 37.5 mcg daily (n = 246) or as Norplant (n = 453). No adverse effects on infant growth through the first year were found in comparison to standard measurements.[ 19 , 20 ] In a cohort study of 71 nursing women who took levonorgestrel as a postcoital contraceptive, none noticed any adverse effect in their infants.[ 8 ]

Effects on milk supply

Among a cohort study of 71 women who took levonorgestrel as a postcoital contraceptive during nursing, none reported any obvious decrease in milk supply after the drug was used.[ 8 ] A study of 1158 postpartum randomized women using the lactational amenorrhea method (LAM) for birth control randomized to be given levonorgestrel as a postcoital contraceptive or given nothing. No difference in the duration of breastfeeding was found between women who used the levonorgestrel and those who did not.[ 9 ] In a nonrandomized, nonblinded study comparing women who were breastfeeding at discharge, 102 postpartum women received depot medroxyprogesterone acetate (dosage not stated) in the early postpartum period (average 51.9 hours postpartum; range 6.25 to 132 hours), 181 received another progestin-only contraceptive and 138 used nonhormonal contraception. No differences in breastfeeding rates were seen at 2 and 6 weeks, but women receiving any hormonal contraceptive were breastfeeding at a lower rate (72.1% vs 77.6%) at 4 weeks postpartum. The authors concluded that progestin-only contraception initiated in the early postpartum period had no adverse effects on breastfeeding rates.[ 21 ] A study analyzed data from a prospective cohort study of U.S. women from May 2005 through June 2007. Women were followed from the third trimester of pregnancy throughout the first year postpartum. Data from the subset of women who professed that intended to breastfeed for 3 months or longer postpartum during their third trimester of pregnancy and who were using a contraceptive at 3 months postpartum were analyzed (n = 1349). Women who intended to breastfeed for at least 4 months and were taking a progestin-only oral contraceptive, such as levonorgestrel, were 3.15 times more likely to be breastfeeding (exclusive or nonexclusive) at 4 months than women who used a nonhormonal contraceptive. Women who said they would breastfeed for 3 to 4 months had 4-month breastfeeding rates equivalent to those

Levels in milk

Levonorgestrel is a synthetic progestin that is the active isomer of the racemate norgestrel. It is considered to be twice as potent on a weight basis as the racemic mixture. Maternal Levels. Fifteen women who were fully breastfeeding and 8 weeks postpartum were given oral levonorgestrel either alone in a dose of 30 mcg daily or in an estrogen-containing oral contraceptive in a dose of 150 mcg or 250 mcg daily. Five women received each dose for 10 days before breastmilk sample collection. With the 30 mcg dose, the drug was undetectable in all of the women in prenursing milk ( 0.05 mcg/L) or postnursing milk ( 0.1 mcg/L) at 3 to 23 hours after the dose. With the 150 mcg dose, the highest levels in milk were found 3 hours after the dose with foremilk and hindmilk levels of 0.34 and 0.54 mcg/L, respectively; levels decreased to 0.11 and 0.17 mcg/L, respectively, at 23 hours after the dose. With the 250 mcg dose, the highest levels in milk were found 3 hours after the dose with foremilk and hindmilk levels of 0.51 and 1.05 mcg/L, respectively; levels decreased to 0.22 and 0.38 mcg/L, respectively, at 23 hours after the dose. The authors estimated that fully breastfed infants would receive 0.4 to 0.5 mcg daily in breastmilk, or about 0.1% of the total (not weight-adjusted) maternal dose.[ 11 ] Two women with well-established lactation (exact time postpartum not stated) were given an oral contraceptive containing 150 mcg of levonorgestrel daily. Each had breastmilk levels measured on 2 occasions 10 to 12 hours after a dose between days 6 and 20 of use. The average of their levonorgestrel milk levels was 0.18 mcg/L (range 0.135 to 0.223 mcg/L).[ 12 ] Milk levonorgestrel levels were measured in 4 women after daily ingestion of oral levonorgestrel 50 or 150 mcg started after 3 months postpartum. Peak milk levonorgestrel levels occurred between 1 and 3 hours and were in the ranges of 0.06 to 0.2 mcg/L after the 50 mcg dose and 0.35 to 0.45 mcg/L after the 150 mcg dose. After

Alternatives LactMed lists

• Etonogestrel
• Intrauterine Copper Contraceptive
• Medroxyprogesterone Acetate
• Norethindrone