Fig. 6.

Estimated growth trajectories and relative differences for different levels of NO₂ exposure for bi-parietal diameter stratified by maternal smoking status. Top panels show estimated growth trajectories for minimum exposure (solid lines) compared maximum exposure (dashed line). Bottom panels show the difference in these trajectories expressed in units of SD scores. The models are adjusted for parity, age, sex, smoking, social class, maternal height and weight. To aid interpretation, x axis is truncated below 25 weeks.