Perinatal outcomes of spontaneous single fetal death in monochorionic twin pregnancies: A single-center retrospective study

Chunyan Deng¹Shiyu Chen²Guiqiong Huang¹Xiaodong Wang¹Haiyan Yu^1*

• ¹Department of Obstetrics, West China Second University Hospital, Sichuan University, Chengdu, China
• ²Department of Ultrasound, Department of Obstetrics, West China Second University Hospital, Sichuan University, Chengdu, China

Objective: The aim of this study was to investigate the perinatal outcomes of surviving co-twins after spontaneous single intrauterine fetal death (sIUFD) in monochorionic (MC) twin pregnancies and to assess the risk of cerebral injury. Methods: This retrospective study was conducted on MC twin pregnancies resulting in spontaneous single intrauterine fetal death at our hospital between January 2012 and December 2023. When termination of pregnancy (TOP) and co-twin deaths were excluded, the patients were subdivided into two groups according to their gestational age at single fetal death: Group 1, < 24 weeks; Group 2, ≥ 24 weeks. Results: There were 90 MC twins, 2 patients with co-twin late death, 19 patients with TOP, and 69 patients continuing pregnancy were included. The gestational age (GA) at single fetal death was 24.0 ± 5.95 weeks, Kaplan-Meier survival curve indicated that the risk of neurological damage and/or fetal anemia increases with GA at sIUFD. Meanwhile, ROC curve showed that GA at sIUFD is a predictor of cerebral lesions, and the lowest risk of cerebral damage for the co-twin occurred before 25+6 weeks of gestation. Among the 69 continuing pregnancies, the delivery age was 35.1±3.3 weeks, and the birth weight was 2355.0 ± 681.0 g. The rates of preterm birth and NICU admission were 62.3% and 50.7%, respectively. Cerebral injury was detected in 10 neonates, three newborn deaths due to cerebral damage caused by extreme prematurity, and two infants (2.9%) with neurological abnormalities. The neonatal outcomes were compared between Group 1 and Group 2. The average gestational age at delivery (36.6 ± 3.3 vs. 33.7 ± 2.5, p=0.000) and birth weight (2639.5 ± 705.2 g vs. 2074.9 ± 546.9 g, p=0.000) were greater in the Group 1. The gestational age of patients with sIUFD was negatively correlated with delivery age, with a Spearman's rho =-0.588** p=0.000) . Conclusions: GA at sIUFD is a predictor of cerebral lesions, the greater the gestational age of sIUFD is, the higher the risk of brain injury among surviving co-twins. There was a negative correlation between gestational age at sIUFD and delivery age in this study.