title: The importance of early weight gain in the intrauterine growth and birth weight of twins.
abstract: OBJECTIVE
  It was our objective to evaluate the association between early maternal weight gain (before 20 weeks), midpregnancy weight gain (20-28 weeks), and late pregnancy weight gain (28 weeks to birth) with fetal growth and birth weight in twins.
  
  
  METHODS
  This historic cohort study was based on 1564 births of live twins >/=28 weeks' gestation from Baltimore, Maryland, Miami, Florida, Charleston, South Carolina, and Ann Arbor, Michigan.
  
  
  RESULTS
  Early fetal growth was affected only by smoking and chorionicity. Factors in models of both mid and late fetal growth included maternal age, pregravid weight, parity, rates of early pregnancy and midpregnancy maternal weight gain, smoking, and pre-eclampsia. Increased midpregnancy fetal growth was associated with early maternal weight gain (10.91 g/wk per pound per week) and midpregnancy maternal weight gain (15.89 g/wk per pound per week). Increased late fetal growth was associated with early maternal weight gain (16.86 g/wk per pound per week) and midpregnancy maternal weight gain (23.88 g/wk per pound per week). Increased birth weight was associated with early (283.02 g per pound per week), mid (163.58 g per pound per week), and late (69.76 g per pound per week) maternal weight gains.
  
  
  CONCLUSIONS
  These findings confirm the importance of early maternal weight gain in twin fetal growth and birth weight.
authors.affiliation: Department of Obstetrics and Gynecology, University of Michigan Medical School, University of Michigan, Ann Arbor, MI, USA.
authors.forename: B
authors.initials: B
authors.lastname: Luke
authors.forename: S J
authors.initials: SJ
authors.lastname: Min
authors.forename: B
authors.initials: B
authors.lastname: Gillespie
authors.forename: M
authors.initials: M
authors.lastname: Avni
authors.forename: F R
authors.initials: FR
authors.lastname: Witter
authors.forename: R B
authors.initials: RB
authors.lastname: Newman
authors.forename: J G
authors.initials: JG
authors.lastname: Mauldin
authors.forename: F A
authors.initials: FA
authors.lastname: Salman
authors.forename: M J
authors.initials: MJ
authors.lastname: O'Sullivan
mesh_terms: D000328:Adult; D001724:Birth Weight; D015331:Cohort Studies; D005314:Embryonic and Fetal Development / Q000502:physiology; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000502:physiology*; D014427:Twins; D015430:Weight Gain / Q000502:physiology