How it works
Frequent breastfeeding, including at night, changes hormone levels in a way that stops the ovaries releasing eggs. If feeds become less frequent, ovulation can restart, sometimes before the first period.
People who are exclusively breastfeeding in the first 6 months and want a short-term, hormone-free option.
How effective is it?
Typical use
98%
In real life about 2 in 100 people get pregnant in a year with typical use.
Perfect use
Over 99%
About 0.5 in 100 when used exactly as directed every time.
Only while all three conditions are met: baby under 6 months, fully or nearly fully breastfeeding, and no periods
See how it ranks against every method in the effectiveness chart.
How to use it
Check that all three conditions apply: your baby is under 6 months, you breastfeed fully or nearly fully with no long gaps between feeds day or night, and you have had no period since giving birth.
Breastfeed on demand, including at night; regular formula, solid foods, long gaps between feeds or relying on expressing milk can make LAM less effective.
Plan your next method early, ideally with a midwife, doctor or nurse before or soon after the birth.
Start another method straight away as soon as any one of the three conditions stops applying.
Pros and cons
Advantages
- No hormones, devices or cost
- Works naturally alongside breastfeeding
- Highly effective while all three conditions are met
- Acceptable to people who prefer not to use other methods
Disadvantages
- Only works for up to 6 months after birth
- Stops working as soon as feeds become less frequent, solids or formula are added, or periods return
- Hard to rely on if you go back to work or are often away from your baby
- Does not protect against STIs
Effect on periods: Periods usually stay away while you fully breastfeed; once they return, LAM no longer works.
Possible side effects
- No side effects of its own
- Vaginal dryness, which is common while breastfeeding (not caused by LAM)
- Pregnancy risk if feeds become less frequent without starting another method
Who it may not suit
A clinician checks your medical history before you start. This list is not complete.
May not be suitable if
- You are not breastfeeding, or are combining breastfeeding with regular formula feeds
- Your baby is over 6 months old or your periods have returned
- You are often separated from your baby for long stretches, or rely mainly on expressing milk
- A pregnancy soon after birth would be very risky for your health
Get medical help if
- You have any bleeding after the first 8 weeks after birth, as it may mean your fertility is returning
- You think you may be pregnant
- You want to start another method, as many are safe while breastfeeding
Frequently asked questions
Can you get pregnant while breastfeeding?
Yes. Breastfeeding only reliably prevents pregnancy if your baby is under 6 months, you are fully or nearly fully breastfeeding day and night, and your periods haven't returned. If any of these stops being true, you need another method.
How effective is breastfeeding as contraception?
When all three LAM conditions are met, about 2 in 100 people get pregnant in the first 6 months. Effectiveness drops quickly once feeding becomes less frequent.
Can I get pregnant before my first period after birth?
Yes. You release an egg about two weeks before a period, so you can be fertile before you notice any bleeding. That is why another method is needed as soon as one LAM condition stops applying.
Does pumping or expressing milk count for LAM?
LAM is based on direct breastfeeding. Relying a lot on expressing, giving bottles or having long gaps between feeds may make it less effective, so ask a clinician about a backup method.
What contraception can I use while breastfeeding?
Many methods are safe while breastfeeding, including the implant, IUDs, the progestogen-only pill, the injection and condoms. Combined hormonal methods are usually not advised in the first weeks after birth; a clinician can advise.
Sources
Reviewed 1 November 2026. We link to the guidance itself so you can check it.