BMI <23 kg/m2 BMI ≥23 kg/m2
Loss Moderate gain Excess gain Loss Moderate gain Excess gain
(>1 kg/m2) (1 to <3 kg/m2) (≥3 kg/m2) (>1 kg/m2) (1 to <3 kg/m2) (≥3 kg/m2)
Outcomes of second pregnancy RR (95% CI) RR (95% CI) RR (95% CI) RR (95% CI) RR (95% CI) RR (95% CI) P-interaction
Offspring birth weight
Normal 2.5 to <4 kg
Low <2.5 kg 1.22 (0.79, 1.90) 0.84 (0.63, 1.11) 1.07 (0.72, 1.59) 1.64 (1.09, 2.47) 1.43 (0.99, 2.07) 1.06 (0.66 2.71) 0.076
High ≥4 kg 0.52 (0.07, 4.04) 1.30 (0.56, 3.02) 3.00 (1.17, 7.68) 0.93 (0.46, 1.86) 1.01 (0.58, 1.76) 1.34 (0.74, 2.43) 0.428
Offspring birth size
AGA 10 - 90 percentile
SGA <10 percentile 0.96 (0.63, 1.45) 0.84 (0.67, 1.06) 0.88 (0.62, 1.25) 1.54 (1.02, 2.34) 1.29 (0.91, 1.83) 0.90 (0.58, 1.42) 0.078
LGA >90 percentile 0.73 (0.49, 1.09) 1.16 (0.96, 1.40) 1.67 (1.30, 2.15) 0.88 (0.71, 1.10) 1.13 (0.97, 1.31) 1.23 (1.03, 1.46) 0.092
Preterm delivery <37 weeks
No
Yes 1.03 (0.65, 1.65) 0.82 (0.60, 1.12) 1.24 (0.81, 1.88) 1.09 (0.74, 1.61) 1.13 (0.83, 1.53) 1.02 (0.71, 1.48) 0.327
Gestational diabetes
No
Yes 1.22 (0.76, 1.95) 1.11 (0.83, 1.48) 1.77 (1.20, 2.61) 0.99 (0.74, 1.31) 1.27 (1.03, 1.58) 1.50 (1.20, 1.88) 0.541
Mode of delivery
Vaginal delivery
Elective caesarean 1.10 (0.89, 1.36) 1.09 (0.97, 1.22) 1.09 (0.92, 1.28) 0.97 (0.84, 1.13) 0.97 (0.88, 1.07) 1.02 (0.91 1.16) 0.348
Emergency caesarean 1.34 (0.96, 1.88) 1.31 (1.07, 1.59) 1.35 (1.04, 1.77) 0.98 (0.82, 1.17) 1.06 (0.91, 1.24) 1.05 (0.89, 1.23) 0.133