Emergency Contraception While Breastfeeding

Levonorgestrel

Levonorgestrel is a synthetic progestin now used in a single dose of 1.5 mg orally, although two 0.75 mg doses 12 hours apart were previously used. Only small amounts of levonorgestrel appear in breast milk. A study of 12 women who received the 1.5 mg dose had amounts in milk that would provide the infant a dose of 1.6 μg of levonorgestrel in the first 24 hours, 0.3 μg in the second 24 hours, and 0.2 μg in the third 24 hours after the dose. Peak milk levels of levonorgestrel occurred 3.9 hours after the dose and milk levels fell with a mean half-life of 26 hours.

Three studies found no adverse effects of emergency contraception with levonorgestrel in nursing mothers. In the largest of the studies, women using LAM alone were compared with those who used LAM plus levonorgestrel as an emergency contraceptive. No differences in adverse effects on the milk supply or on infant's weight, length, head circumference, chest circumference, or mid-arm circumference at 3 and 6 months postpartum, and Denver Developmental Screening Test results at 6 months postpartum were observed between the groups. After use of levonorgestrel as a postcoital contraceptive, nursing can resume 3–4 hours after the dose.

Ulipristal

Ulipristal acetate is a selective progesterone receptor modulator used in a single 30 mg oral dose as an emergency postcoital contraceptive. Ulipristal is metabolized to mono- and didemethylated metabolites. Monodemethyl-ulipristal is pharmacologically active.

Recommendations on ulipristal's use during breastfeeding have changed considerably over time. When it was originally marketed in the United States in 2014, it was recommended that it not be used during breastfeeding. In 2015, World Health Organization (WHO) guidelines recommended a 1-week period of breastfeeding abstinence after its use, apparently based on its serum half-life. ⁴ In 2016, Centers for Disease Control and Prevention (CDC) guidelines recommended only a 24-hour waiting period. ³

Then, in 2018 U.S. labeling was revised to conform to the U.S. Food and Drug Administration's Pregnancy and Lactation Labeling Rule, with no waiting period specified. Instead product labeling states, “The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for (ulipristal) and any potential adverse effects on the breastfed child from (ulipristal) or from the underlying maternal condition.”

The change in labeling is apparently related to an unpublished study described in the package insert. Milk was collected in a study in 12 lactating women in 24-hour increments to measure the concentrations of ulipristal acetate and the active metabolite, monodemethyl-ulipristal acetate. Using these data, a fully breastfed infant would receive ∼4.1 μg/kg of drug plus active metabolite on the first day and a total of 5.2 μg/kg over a 5-day period. These amounts correspond to a weight-adjusted dosage of 0.8% of drug plus active metabolite on the first day and a total of 1% of the maternal dose for 5 days. Although it would be ideal to have safety data in nursing infants, the labeling implies that no waiting period is required after use of ulipristal, which is consistent with the very low amounts in milk.

Yuzpe Regimen

This old regimen consists of 100 μg of ethinyl estradiol plus 0.50 mg of levonorgestrel (two high-estrogen oral contraceptive tablets) given twice 12 hours apart. This regimen is less effective than other methods and has higher rates of nausea and vomiting, so it is not often used. It has not been studied during lactation, but based on studies with oral contraceptives, the amounts of estrogen and progestin in milk are probably not sufficient to affect the infant with this short-term dosage regimen. The estrogen might interfere with milk production, at least temporarily.

Copper IUD

The copper IUD has been studied extensively during lactation in comparison with other forms of contraception. It is considered to be the most effective emergency contraceptive and does not affect lactation performance. A 2016 systematic review found that the risks for adverse events among IUD users, including expulsion, pain, and removals, were similar or lower for breastfeeding women than for nonbreastfeeding women. However, uterine perforation with IUDs, although rare, was more frequent among breastfeeding women during the early postpartum period. ⁵ These studies were not performed in women who received the IUD for emergency contraception.

The effects on maternal copper metabolism during breastfeeding were compared in three groups of women. Two groups used older copper-containing IUDs (Copper 380A and Copper 200B) and a third group that did not use any IUD served as controls. Milk samples were collected before insertion at 10 weeks postpartum and 6 weeks after insertion. Milk copper concentrations ranged between 0.25 and 0.31 μg/g of milk in the various groups before and after insertion. No statistically significant difference in milk copper levels was found before and after 6 weeks in the IUD groups or between the copper IUD groups and the control group.

Mifepristone

Mifepristone has been used overseas for emergency contraception in various dosages: 2 doses of 25 mg orally 12 hours apart, 10 mg/day for 3 days, or 10 mg/day for 5 days. ¹ These mifepristone dosages are lower than the 200 mg dose used with misoprostol for pregnancy termination. As emergency contraception, low-dose mifepristone (<25 mg) is probably less effective than mid-dose (25–50 mg) mifepristone, but both were more effective than levonorgestrel given as two doses of 0.75 mg. ¹

The only study of mifepristone during lactation was done with high doses. Twelve women (most 6–12 months postpartum) who had undergone a medical abortion using mifepristone and misoprostol provided milk samples for up to 5 days after the procedure for measurement of mifepristone. In the two women who received the standard single dose of 200 mg orally, mifepristone was undetectable in breast milk at all times. Ten women received a single oral dose of 600 mg of mifepristone. Their breast milk levels of mifepristone were highest in the samples collected between 6 and 9 hours after drug administration, and total milk excretion averaged 172 μg/L on day 1. The authors estimated that a fully breastfed infant would receive a weight-adjusted dosage of only 0.5% of the maternal dosage and suggested that breastfeeding need not be interrupted after a single dose of mifepristone.

Misoprostol, which is used in a dosage of 800 μg with 200 mg of mifepristone, has been studied in oral doses as high as 600 μg. Amounts ingested by the infant would amount to less than a microgram and would not be expected to cause any adverse effects in breastfed infants.

Postemergency Contraception

Numerous options are available for long-term contraception after emergency contraception. If a copper IUD was inserted, it will provide reversible contraception for at least 10 years. Other nonhormonal methods (condoms, diaphragms, etc.) can be used immediately after emergency contraception. CDC guidelines recommend that the woman should either abstain from sexual intercourse or use a barrier contraceptive for the next 7 days after starting or resuming regular contraception or until her next menses, whichever comes first. ³

Hormonal methods should not be started until 5 days after ulipristal acetate because they might interfere with its activity. Otherwise, progestin-only oral (levonorgestrel, norethindrone), IUDs (levonorgestrel) injectable (depot medroxyprogesterone), and implants (etonogestrel or levonorgestrel) can be started immediately after emergency contraception. WHO guidelines recommend against injectable progestins before 6 weeks postpartum, but CDC guidelines do not.^3,4

Estrogen-containing contraceptives (oral, patches, vaginal rings) are usually avoided in nursing mothers because they might interfere with lactation. However, this is a dose- and time-related effect. Various guidelines differ on the time when estrogen-containing contraceptives can be initiated.^3,4,6 CDC guidelines recommend that combined oral contraceptives not be started until 3–4 weeks postpartum because of the risk of venous thromboembolism, and disadvantages of using this method generally outweigh the advantages until 6 weeks postpartum.

WHO guidelines state that they should not be used in nursing mothers before 6 weeks postpartum, and the disadvantages of using this method generally outweigh the advantages between 6 weeks and 6 months postpartum. Academy of Breastfeeding Medicine guidelines recommend that breastfeeding mothers use combined contraceptives with lowest possible dose of estrogen as late as possible into well-established breastfeeding. ⁶

Summary

The medications and copper-containing IUD used for emergency contraception pose no apparent risk to the breastfed infant. The copper IUD, ulipristal acetate, and mifepristone are more effective than levonorgestrel. The Yuzpe regimen should be avoided because it is the least effective method, causes more maternal adverse effects, and might adversely affect the milk supply. IUDs and progestin-only products are preferred in nursing mothers for long-term contraception after emergency contraceptive use.