Birth Weight-discordance in Twins Pregnancy: a Multicenter Retrospective Study

The rate of twin pregnancies in China has increased by 50 percent over the past decade and now stands at about 3 percent. This is significantly higher than the European and American countries. There are significant differences in birth weight of some newborns, that is, birth weight-discordance in twin pregnancies (BWDT). BWDT was significantly associated with fetal death, preterm birth, neonatal death, and neonatal complications. Existing studies mainly focus on the perinatal outcomes of mothers and infants with BWDT, or are reported from small samples in developed countries. The investigators are aware of the need to further explore the occurrence of birth weight inconsistency and adverse neonatal outcomes in China with a large sample. Through retrospective study design, the investigators will collect clinical data of live twin births at multiple study sites, investigate the incidence of BWDT, and analyze its adverse outcomes.

Inclusion Criteria:live twin births1. delivered from 2018 to 2020Exclusion Criteria:congenital and hereditary diseasesinherited metabolic diseasescomplex congenital heart diseasedigestive tract malformations