Correlation between second trimester weight gain and perinatal outcomes in dichorionic twin pregnancies: The LoTiS cohort study

Purpose: To investigate how second trimester gestational weight gain relates to perinatal outcomes in twin pregnancies of the LoTiS cohort in Chongqing, China. Methods: A cohort study was conducted among women with dichorionic twin pregnancies; pregnancies that culminated in delivery at ≥20 gestational weeks were included in the analysis (n = 177). Data were collected through the Longitudinal Twin Study (LoTiS). The second trimester was divided into two periods: 12–20 and 21–28 gestational weeks. Correlations between maternal weight gain and perinatal outcomes were estimated using linear or logistic regression models; the crude OR and adjusted OR were calculated. Results: The average total gestational weight gain for the whole pregnancy was 17.71 ± 4.98 kg and average gestational weight gains during 12–20 gestational weeks and 20–28 gestational weeks were 5.11 ± 1.81 kg and 5.84 ± 2.05 kg, respectively. Insufficient gestational weight gain was associated with higher risk of preterm birth (OR = 0.92, 95% CI 0.86-0.99) and spontaneous preterm birth (OR = 0.89, 95% CI 0.82–0.97). Reduced gestational weight gain during 12–20 gestational weeks was associated with higher risk of small for gestational age. Additionally, the mean birth weight of a twin pair increased by 45.78 g or 13.03 g when gestational weight gain during 12–20 weeks or total gestational weight gain increased by 1 kg. Conclusion: Maternal weight gain in the early second trimester was correlated with birth weight in dichorionic twins.