Risk ratios are adjusted for maternal age and BMI at 12-week gestation in the first pregnancy, ethnicity, interpregnancy interval and respective pregnancy outcomes in the first pregnancy. BMI stable (-1 to < 1 kg/m2) serves as the reference group. RR, risk ratio; CI, confidence interval; AGA, appropriate for gestational age; SGA, small for gestational age; LGA, large for gestational age.