title: Secular trends of low birthweight and macrosomia and related maternal factors in Beijing, China: a longitudinal trend analysis.
abstract: BACKGROUND
  Information tracking changes of birthweight is scarce in China. To examine trends of low birthweight (birthweight < 2500 g) and macrosomia (birthweight ≥ 4000 g) and potential risk factors in Beijing, hospital records from two major obstetrics and gynecology hospitals in urban districts in Beijing were analyzed.
  
  
  METHODS
  Hospital records from 1996 to 2010 were retrieved. Information of prenatal examination and birth outcomes was entered into a structured database. Live births were used for trend analysis. Information of live births in 2010 was used to identify potential risk factors.
  
  
  RESULTS
  A total of 63 661 live births were delivered during 1996-2010 in the study hospitals. The average birthweight increased from 3271 g in 1996 to 3 359 g in 2000 and slightly declined to 3 331 in 2010. The percentage of low birthweight fluctuated around 4.0%. No significant increase or decrease was observed. Preterm birth was the main cause of low birthweight, accounting for more than 73% of low birthweight. The average percentage of macrosomia was 7.6%. The percentages of macrosomia increased from 6.6% in 1996 to 9.5% in 2000 and declined to 7.0% in 2010. Excessive gestational weight gain and gestational diabetes were significantly associated with macrosomia.
  
  
  CONCLUSIONS
  Continuously monitoring abnormal birthweight is needed and intervention should focus on appropriate gestational weight gain and reduction of preterm birth and gestational diabetes.
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Shan
authors.forename: Fangfang
authors.initials: F
authors.lastname: Chen
authors.forename: Wenpeng
authors.initials: W
authors.lastname: Wang
authors.forename: Juan
authors.initials: J
authors.lastname: Zhao
authors.forename: Yue
authors.initials: Y
authors.lastname: Teng
authors.forename: Minghui
authors.initials: M
authors.lastname: Wu
authors.forename: Honghong
authors.initials: H
authors.lastname: Teng
authors.forename: Xue
authors.initials: X
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Qi
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Liu
authors.forename: Chunying
authors.initials: C
authors.lastname: Tan
authors.affiliation: Department of Epidemiology, Capital Institute of Pediatrics, Beijing 100020, China. jiemi@vip.163.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Mi
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D016640:Diabetes, Gestational / Q000453:epidemiology*; D005260:Female; D005320:Fetal Macrosomia / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D015430:Weight Gain