Birth Weight-discordance in Twins Pregnancy: a Multicenter Retrospective Study
Condition: Twin; Pregnancy, Affecting Fetus or Newborn
MeSH terms: Birth Weight
Study type: Observational

Summary: 
      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.
    

Detailed description: 
      The investigators adopted a multicenter retrospective case-control study design and enrolled
      live twin births delivered from 2018 to 2020 in 22 hospitals in 12 provinces in China.
      Children with congenital and hereditary diseases, such as inherited metabolic diseases,
      complex congenital heart disease, and digestive tract malformations, were excluded from the
      study. The investigators collected the following information: (1) General information:
      maternal age, year of delivery, number of delivery, mode of conception, mode of delivery,
      chorionic nature, education level, newborn sex; (2) Maternal risk factors associated with
      intrauterine development: induced abortion ≥2 times, placental disease, uterine tumor,
      gestational diabetes mellitus, gestational hypertension disease, intrahepatic cholestasis,
      connective tissue disease, hypothyroidism, and chorionic amnitis; (3) Infant birth outcome:
      gestational age, birth weight, birth length, birth head circumference, very low birth weight
      infants, ultra-low birth weight infants, the Apgar score, whether transferred to neonatology
      department. (4) Information of hospitalization during the neonatal period: Pulmonary
      surfactant use, duration of oxygen therapy, neonatal complications (i.e., pulmonary
      hemorrhage, BPD, NEC, PDA, ROP, PVL, IVH, anemia, infection, etc.), feeding status (i.e.,
      duration of milk opening, duration of full feeding, feeding style and feeding materials at
      full feeding, Time to recovery of birth weight), and discharge outcome (i.e., total
      hospitalization cost, length of stay, gestational age corrected for discharge, discharge
      status, discharge physique).
    

Observational model: Case-Control
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        live twin births
      
Keywords: twins; birth weigh-discordant; occurrence; birth outcomes; multi-center study