Maternal characteristics and birth outcomes and relative change throughout the study period, 1994–2009.

§Relative change was calculated by: [(2009 rate –1994 rate)/(1994 rate)].*100; Test-for-trend was significant for all factors except stillbirths and multiple births, P†Low risk pregnancies defined as primiparae, aged 20–34 years, without pregnancy complications; and with a liveborn singleton infant, born in cephalic presentation and of normal fetal growth at the 10th–90th birth weight percentile of the distribution for gestational age and infant sex. [16].*Numbers may not add up to totals due to missing data or rounding.