Contraception after birth

Fertility can return before the first postpartum period, so contraception decisions are made on timing rather than on bleeding.

When fertility returns

• Ovulation can occur from day 21 after birth in people who are not breastfeeding. UK FSRH guidance therefore advises that contraception is needed from day 21 onwards.
• In fully breastfeeding people, ovulation is typically delayed, but the first ovulation may precede the first bleed — so waiting for a period is not a method.

Lactational amenorrhoea method (LAM)

LAM is genuinely effective, but only when all three conditions hold at once:

1. Under 6 months since birth
2. Fully or nearly fully breastfeeding, on demand, day and night, with no long gaps
3. Periods have not returned

Meeting all three gives around 98% effectiveness (roughly 2 pregnancies per 100 women in the first 6 months). Failing any one of them — introducing formula or solids, using a pump instead of feeding, a night gap, or any bleeding after day 56 — ends LAM and another method is needed.

Method options after birth

Combined hormonal contraception is restricted in the first weeks because of postpartum venous thromboembolism risk, which is highest in the first 21 days. WHO and FSRH place it at MEC category 4 (do not use) before day 21 regardless of feeding, and category 2 from 6 weeks while breastfeeding. Evidence that it meaningfully reduces milk supply after lactation is established is weak; the timing restriction is driven mainly by clotting risk.

Progestogen-only methods do not reduce milk supply — this is consistently supported by the Cochrane review on hormonal contraception during lactation, and by WHO MEC, which places them at category 1 or 2 from birth.

Immediate postpartum IUD insertion (within 48 hours) is recommended by WHO and ACOG. Expulsion rates are higher than for interval insertion — roughly 10–27% versus 3–5% — but overall continuation is higher because the opportunity is not missed.

Pregnancy spacing

WHO recommends an interpregnancy interval of at least 24 months after a live birth, and at least 6 months after a miscarriage or abortion. Intervals under 18 months are associated with increased preterm birth, low birthweight and small-for-gestational-age risk. This is guidance for planning, not a judgement on shorter intervals that have already happened.

Emergency contraception after birth

Needed from day 21 if unprotected sex occurs. Copper IUD cannot be used between 48 hours and 4 weeks postpartum. Levonorgestrel is compatible with breastfeeding; ulipristal acetate requires expressing and discarding milk for 7 days (FSRH), so levonorgestrel or a copper IUD after 4 weeks is often preferred.

When to see a clinician

Contraception should be discussed before discharge and at the 6–8 week check. Seek advice sooner if you have had unprotected sex after day 21, if bleeding restarts, or if you want a long-acting method fitted.

Sources

• FSRH, Contraception After Pregnancy guideline, 2017 (amended 2020).
• WHO, Medical Eligibility Criteria for Contraceptive Use, 5th edition, and 2015 postpartum update.
• Lopez LM et al., Cochrane Database of Systematic Reviews, 2015 (hormonal contraception during lactation).
• WHO, Report of a Technical Consultation on Birth Spacing, 2005.
• ACOG Committee Opinion 670, Immediate Postpartum LARC, 2016.