Estimated change in mean gestational weight gain with increasing maternal body mass index, for nulliparous and multiparous women. Estimated effect showing the difference in effect between nulliparous (parity 0; blue line) and multiparous (parity 1; red line) women. The deviation from the dotted line represents the extent to which gestational weight gain (GWG) decreases in multiparous women and nulliparous women as body mass index (BMI) increases
