Yes, you can take the morning-after pill while breastfeeding. The most commonly available version, sold as Plan B and its generics, contains levonorgestrel and is considered safe during lactation. Only about 0.1% of the dose you take reaches your baby through breast milk, and studies show infants can break down and clear that tiny amount without it building up in their system.
That said, there are two different types of morning-after pill available in the U.S., and the guidance differs slightly between them. Here’s what you need to know about each one, whether you need to pause breastfeeding, and what alternatives exist.
Levonorgestrel (Plan B) Is the Preferred Option
Levonorgestrel is the active ingredient in Plan B One-Step and its generic versions. It’s available over the counter without a prescription. This is the morning-after pill most commonly recommended for breastfeeding women because its safety profile during lactation is well studied. A fully breastfed infant receives roughly 0.4 to 0.5 micrograms through milk, which works out to about 0.1% of what you took. When researchers measured infant blood levels, they found concentrations were just 1 to 2% of the mother’s peak levels, confirming that very little crosses over and even less stays in the baby’s system.
Multiple studies have tracked breastfed infants whose mothers used levonorgestrel. In one trial comparing 250 exposed infants to 250 unexposed infants, there were no differences in height or weight gain over nine months. A separate study compared 100 breastfed babies whose mothers took levonorgestrel as emergency contraception to 100 babies whose mothers did not. At three and six months, the two groups showed no significant differences in weight, length, head circumference, or developmental screening results. In a cohort of 71 nursing women who took levonorgestrel after unprotected sex, none reported any adverse effects in their infants.
You Don’t Need to Pump and Dump
Some product packaging suggests avoiding breastfeeding for eight hours after taking levonorgestrel. This recommendation is not supported by research. In one study, 75% of breastfeeding mothers resumed nursing before the eight-hour mark, and none observed any negative effects in their babies. The Breastfeeding Network and the LactMed database (maintained by the National Institutes of Health) both support continuing to breastfeed as normal after taking levonorgestrel. There is no need to pump and discard your milk.
No changes in milk supply have been reported with levonorgestrel emergency contraception. Since it’s a single dose rather than ongoing hormonal contraception, any hormonal exposure through your milk is brief.
Ulipristal (ella) Requires More Caution
The other morning-after pill available in the U.S. is ulipristal acetate, sold under the brand name ella. It requires a prescription and works through a different mechanism than levonorgestrel. Older guidance recommended pumping and discarding your milk for 24 hours after taking ella, but current FDA-approved labeling no longer includes that requirement.
Still, ulipristal has been studied far less in breastfeeding women than levonorgestrel. If you have a choice between the two and you’re nursing, levonorgestrel is the more straightforward option with a deeper evidence base. If you do take ella, talk to your pharmacist or provider about whether a brief pause in nursing makes sense for your situation.
How Effectiveness Compares
Both types of morning-after pill work best when taken as soon as possible, ideally within three days (72 hours) of unprotected sex. Within that window, levonorgestrel and ulipristal have similar effectiveness. Between three and five days, ulipristal tends to be more effective. Both can be taken up to five days after unprotected intercourse, but effectiveness declines with each day you wait.
One factor worth knowing: levonorgestrel may be less effective for women with a higher body weight. If this applies to you, ulipristal or the copper IUD may be better options to discuss with a provider.
The Copper IUD Is Also an Option
If you want the most effective form of emergency contraception, the copper IUD is it. A provider can place one within five days of unprotected sex (some research suggests it works up to 14 days after), and it doubles as long-term birth control for up to 10 years.
The copper IUD is entirely hormone-free, so it has no effect on your milk supply or composition. Researchers measured copper levels in breast milk before and six weeks after IUD insertion and found no significant difference compared to women without an IUD. Milk copper concentrations stayed between 0.25 and 0.31 micrograms per gram of milk across all groups.
One consideration for the early postpartum period: uterine perforation during IUD placement, while rare overall, occurs slightly more often in breastfeeding women shortly after delivery. A 2016 systematic review found that other risks like pain, expulsion, and removal rates were similar or lower for breastfeeding women compared to non-breastfeeding women. If you’re interested, your provider can assess whether the timing is right based on how far postpartum you are.
Breastfeeding Itself Offers Some Protection
If you are fewer than six months postpartum, your period has not returned, and you are exclusively or nearly exclusively breastfeeding (at least 85% of feeds at the breast), you already have a degree of natural pregnancy protection. This is called the lactational amenorrhea method, or LAM. It’s not foolproof, but when all three conditions are met, it’s quite reliable. If any one of those conditions doesn’t apply, your fertility may have already returned, and emergency contraception makes sense if you want to avoid pregnancy.