Study	Reason for exclusion
Gross 2002	Study is part of a World Health Organization trial
Short 1991	No life table rates, no differentiation between full and partial breastfeeding; loss to follow‐ up more than 10% or not specified
Tazhibayev	Aim of the study was promotion of LAM. Endpoints were knowledge of LAM and other contraception methods and number of pregnancies. No details on sexual activity, no pregnancy life tables; no definitions and a lack of clarity for 'menstruation'
Valdes 2000	Aim of the study was to assess the efficacy of LAM under certain conditions. No information on sexual activity; the definition of LAM was unclear, no life tables for menstruation; no definition of menstruation

LAM: lactational amenorrhoea method