Labbok 1997.

Methods	Multicentre prospective study; 11 sites in 10 different countries
Participants	491 women: age 27.5; parity 2.4. Education level 4‐10 years in "developing countries"; 13‐17 in high income countries
Interventions	LAM health education during monthly follow‐up visits checking LAM criteria over 6 months, contact at 9 and 12 months
Outcomes	Efficacy rates of LAM 92.5 to 100 (2718 WMAC). Lactational amenorrhoea alone protected for 98.0 (2828 WMAC)
Notes	3 definitions of menstruation used. Selection bias
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	D ‐ Not used