Check if you meet LAM (Lactational Amenorrhea Method) criteria while breastfeeding. Enter baby’s age, feeding pattern, night feeds, and period status to see if LAM applies, how effective it is, and when to switch methods.
Methodology & Sources
What this estimates
This tool evaluates whether a user currently meets the Lactational Amenorrhea Method (LAM) criteria and, if so, displays an effectiveness estimate for pregnancy prevention during the first 6 months postpartum. If criteria are not all met, it shows a conservative “not reliable / lower & variable” message and recommends switching methods.
Clinical criteria used
- Baby < 6 months old.
- Amenorrhea (no return of menses since birth).
- Fully or nearly fully breastfeeding with day and night feeds (no regular supplementation).
In the calculator, we operationalize this as ≥90% exclusive intake and ≥1 night feed.
These match standard program guidance from WHO/USAID’s Global Handbook and U.S. professional bodies.
Effectiveness band
When all three criteria are met and continue to be met, LAM is typically quoted as ≈98% effective in the first 6 months postpartum. This reflects prospective studies and program experience synthesized in global guidance. Effectiveness drops immediately when any criterion is no longer satisfied (e.g., menses return, regular supplementation, or baby reaching 6 months).
How the calculator maps inputs
- Baby’s age (months): eligible if < 6. We display a countdown to 6 months for switching guidance.
- Menses return: any reported return ends LAM eligibility.
- Exclusive breastfeeding %: values ≥90% are treated as “fully/nearly fully.” If 70–89%, we show “lower & variable” protection and advise switching.
- Night feeds: we expect at least one night feed; otherwise we flag that LAM is not met.
When to switch methods
If eligible, we suggest switching at or before the baby reaches 6 months, or sooner if menses return or feeding patterns change. If not eligible, we advise switching now. Progestin-only options and non-hormonal methods are commonly used during breastfeeding (follow clinician guidance).
Limitations
Estimates represent program criteria and do not account for individual variations (e.g., irregular bleeding, mixed feeding patterns, pumping schedules). Educational use only; not medical advice. Discuss personal circumstances with a clinician.
Sources
- Family Planning: A Global Handbook for Providers — LAM (WHO, USAID, Johns Hopkins CCP): criteria and ~98% effectiveness while criteria are met.
- ACOG — Postpartum Birth Control (patient guidance summarizing LAM effectiveness and conditions).
- FSRH Guideline: Contraception After Pregnancy (UK Faculty of Sexual & Reproductive Healthcare; LAM criteria & effectiveness).
- U.S. Office of Population Affairs — LAM (method overview for patients and clinicians).
How LAM works (fast basics)
- All three must be true for LAM to apply:
- Baby is < 6 months old,
- No bleeding like a period has returned, and
- Exclusive or near-exclusive breastfeeding day & night (frequent feeds; long gaps avoided).
- If any condition changes, switch to another method—LAM protection drops quickly.
What your result means
- Meets LAM: Protection is high in the first 6 months when criteria are strictly followed.
- Doesn’t meet LAM: Treat as not protected and consider a reliable backup (condoms, progestin-only methods, IUD, etc.).
What’s next?
Urgent? If you’re within 120 hours (5 days) of sex, see Morning-After Pill Effectiveness.
FAQ
What are the exact LAM criteria?
How effective is LAM?
Does pumping count?
When should I switch from LAM?
Sources
- CDC — Appendix G. Lactational Amenorrhea Method (LAM) (criteria & use notes).
- Family Planning: A Global Handbook for Providers — LAM chapter (criteria & switching): When Can a Woman Use LAM? and Helping Clients Switch.
Educational info only; not medical advice. Talk with a clinician about postpartum contraception choices.