Comparative influence of inappropriate gestational weight gain on pregnancy outcomes in IVF-conceived and spontaneously conceived twin pregnancies

Objective: To investigate the influence of inappropriate gestational weight gain (GWG) on pregnancy outcomes in twin pregnant women with in vitro fertilization (IVF) treatment. Methods: This retrospective cohort study included 2992 twin pregnant women and categorized the participants as follows: (i) they were classified into spontaneous conception (SC) or IVF groups based on whether they received IVF treatment, and (ii) they were categorized into inadequate, optimal, or excessive GWG groups according to the International Organization for Migration Twin Pregnancy Guidelines. Initially, the study investigated the separate effects of IVF treatment and different levels of GWG on the outcomes of twin pregnancies. Subsequently, after adjusting for confounding factors, multifactorial logistic regression analysis was performed to further investigate the impact of IVF treatment and high GWG on twin pregnancy outcomes. Based on this, the analysis was stratified by whether IVF was used to explore the effects of different GWG levels on each subgroup (those who underwent IVF and those who conceived spontaneously). Finally, potential multiplicative interactions between IVF and different GWG categories were examined to identify their combined effect on pregnancy outcomes. Results: The results showed that women with twin gestations conceived via IVF exhibited significantly higher maternal age, pre-pregnancy body mass index, and a greater incidence of GWG beyond recommended guidelines compared to the SC group. Furthermore, both IVF treatment and inappropriate GWG increased the risk of adverse pregnancy outcomes, respectively. Following adjustments for confounding variables through multifactorial logistic regression, it was demonstrated that both IVF treatment and high GWG significantly elevated the risk of adverse outcomes in twin pregnancies, such as admission to the neonatal intensive care unit. It is noteworthy that inappropriate GWG, combined with IVF treatment, will stepwise increase the incidence of intrahepatic cholestasis of pregnancy, respiratory failure, respiratory distress, pre-eclampsia, maternal intensive care unit admission, and postpartum hemorrhage risk. However, these outcomes were less affected by inappropriate GWG in the SC group. Lastly, this study did not unveil a significant interaction between the IVF procedure and disparate levels of GWG in relation to the adverse outcomes. Conclusion: A high incidence of inappropriate GWG in twin pregnancies with IVF treatment and inappropriate GWG conferred more adverse twin pregnancy outcomes in the IVF group relative to the SC group. This study indicates that proper management of GWG may be a breakthrough in reducing adverse outcomes in twin pregnancies associated with IVF. Therefore, implementing proactive interventions such as supervised exercise programs, prescribed physical or dietary plans, enhanced weight management, or personalized counseling, holds promise for lowering the risks associated with inappropriate GWG in twin pregnancies resulting from IVF.