Another factor that showed significant association with preterm low birth weight was weight gain in pregnancy (<6 kg of weight gain: aOR = 22.42, 95% CI: 7.4 - 67.92; 6 - 9 kg of weight gain: aOR = 4.1, 95% CI: 2.05 - 8.21).
Yếu tố nguy cơ khác là tăng trọng của mẹ trong thai kỳ với: tăng trọng < 6 kg (OR = 22,42, KTC 95%: 7,4 – 67,92), tăng trọng 6 – 9 kg (OR = 4,1, KTC 95%: 2,05 – 8,21).