Fig. 2

Bland and Altman plots for the agreement between self-reported pre-pregnancy weight and weight measured in the BMCNC data: a 30–94 days of pregnancy; b 30–60 days of pregnancy; c 30–45 days of pregnancy. Note: 1. b & a limits: Limits as defined in Bland & Altman (1986): Mean difference ± 1.96 X Standard deviation of the difference. 2. A small number of individuals (n = 18 in A, n = 4 in b and n = 1 in c) were not plotted due to the chosen limits of the plots. 3. There is a small difference in the sample size in the graphs due to missing data in height (n = 5381 for 30–94 days, n = 1617 for 30–60 days, n = 480 for 30–45 days)