Feng Zhoushan ^1* Xiaomei Tong ² Zheng He ³ Chunxia Yang ⁴ Wei Shen ⁵ Yueqin Ding ⁶ Jin Liu ⁷ Qiong Meng ⁸ Aiqin Zhang ⁹ Hong Jiang ¹⁰ Wenkang Yang ¹¹ Jianwu Qiu ¹² Xian Wei ¹³ Yayu Zhang ¹⁴ Xiaobo Lin ¹⁵ Lijun Liu ¹⁶ Ya Jin ¹⁷ Youfen Wei ¹⁸ Xiufang Yang ¹⁹ Yitong Wang ²⁰ Yangfan Cai ²¹ Xinzhu Lin ⁵ Qiliang Cui ¹

• ¹ Department of Neonatology, Guangzhou Key Laboratory of Neonatal Intestinal Diseases, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
• ² Department of Pediatrics, Peking University Third Hospital, Beijing, China
• ³ Department of Neonatology, Sichuan jinxin xinan women and children's hospital, Chengdu, Sichuan Province, China
• ⁴ Department of Neonatology, The Affiliated Hospital of Guizhou Medical University,, Guiyang, Guizhou Province, China
• ⁵ Department of Neonatology, Xiamen Maternal and Child Health Hospital, College of Medicine, Xiamen University, Xiamen, Fujian Province, China
• ⁶ Department of Neonatology, Affiliated Dongguan Shilong People's Hospital of Southern Medical University, Dongguan, China
• ⁷ Department of Neonatology, First Affiliated Hospital of Shaoyang University, Shaoyang, Hunan, China
• ⁸ Department of Neonatology, Guangdong Second Provincial General Hospital, Guangzhou, China
• ⁹ Department of Neonatology, Cangzhou People's Hospital, Guangzhou, China
• ¹⁰ Department of Neonatology, Affiliated Hospital of Yanan university, Guangzhou, China
• ¹¹ Department of Neonatology, Huizhou Central People’s Hospital, Guangzhou, China
• ¹² Department of Neonatology, The Affiliated Yue Bei People's Hospital of Shantou University Medical College, Shaoguan, China
• ¹³ Department of Neonatology, Xiaogan Hospital Affiliated to Wuhan University of Science and Technology, Guangzhou, China
• ¹⁴ Department of Neonatology, The Affiliated Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
• ¹⁵ Department of Neonatology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong Province, China
• ¹⁶ Department of Neonatology, The Third Staff Hospital of Baogang Group Baotou, Baotou, China
• ¹⁷ Department of Neonatology and Pediatrics, Jinan University First Affiliated Hospital, Guangzhou, China
• ¹⁸ Department of Neonatology, Lanzhou University Second Hospital, Lanzhou, Gansu Province, China
• ¹⁹ Department of Neonatology, Zhongshan City People's Hospital, Zhongshan, China
• ²⁰ Department of Neonatology, Binhaiwan Central Hospital of Dongguan, Dongguan, China
• ²¹ Department of Neonatology, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong Province, China

Objective: Prepregnancy overweight or obesity can adversely affect maternal health, but its potential impact on twin infants remains unclear. Study Design: This study collected clinical data on twin births and their mothers from 22 healthcare units across 12 regions in China between January 2018 and December 2020. After screening, a total of 4,724 women with twin pregnancies and 9,448 newborns were included in the study. To control for confounding factors, multiple logistic regression, propensity score matching, inverse probability weighting, and overlapping weighting models were used, allowing for a more comprehensive investigation into the effects of different prepregnancy body mass index categories on Apgar scores and other outcomes. Results: Compared to prepregnancy normal weight, prepregnancy overweight/obesity increased the incidence of larger and smaller twin infants with 1-min Apgar score ≤7 (adjusted OR (95% CI): 1.60 (1.20-2.13) and 1.45 (1.09-1.92), respectively), as well as the incidence of hypertensive disorders of pregnancy and gestational diabetes (adjusted OR (95% CI): 1.85 (1.55-2.21) and 1.49 (1.27-1.74), respectively). Sensitivity analysis revealed that prepregnancy overweight/obesity increased the incidence of 1-min Apgar score ≤7 in twins with gestational age < 34 weeks. These findings were consistent after propensity score matching analysis, inverse probability weighting, and overlapping weighting. Additionally, prepregnancy underweight reduced the rate of twins with 1-min Apgar score ≤7 (0.56 (0.32-0.92) and 0.58 (0.34-0.94), respectively). Different prepregnancy BMI did not have a significant impact on 5-minute Apgar score, birth weight discordance in twins, NICU admission, preterm birth or low birth weight. Conclusion: Maternal overweight/obesity before pregnancy increases the incidence of hypertensive disorders of pregnancy and gestational diabetes in twin pregnancies, and also elevates the risk of twins having a low Apgar score. Therefore, it is imperative to manage weight before pregnancy and prepare for neonatal resuscitation during delivery.