title: Maternal risk factors for small-for-gestational age newborns in Japanese dichorionic twins.
abstract: OBJECTIVE
  To investigate the maternal risk factors for small-for-gestational age (SGA) newborns in Japanese dichorionic (DC) twins.
  
  
  METHODS
  A retrospective study was conducted from 2003 to 2008 on 340 DC twin pregnancies resulting in two live births. Newborns were classified as SGA if their birth weight was below the 10th percentile according to Japanese singleton norms. Statistical differences were evaluated between pregnancies resulting in appropriate-for-gestational age (AGA) pairs and those resulting in at least one SGA neonate.
  
  
  RESULTS
  The study population consisted of AGA/AGA (50.8%), AGA/SGA (37.0%) and SGA/SGA pairs (12.0%). Logistic regression analysis identified significant interrelations for SGA with maternal nulliparity (odds ratio [OR] 0.52, 95% confidence interval [CI] 0.30-0.91), smoking (OR 3.25, 95% CI 1.09-9.66), assisted reproductive technology (OR 0.52, 95% CI 0.30-0.89), pregnancy-induced hypertension (OR 2.00, 95% CI 1.01-4.31), pregravid weight (kg) (unitary OR 0.94, 95% CI 0.91-0.97) and monthly weight gain (kg/month) (unitary OR 0.25, 95% CI 0.14-0.44). Bivariable receiver operating characteristic curves were generated for monthly weight gain (area under the curve [AUC] 0.626, cutoff 1.41 kg/month, P<0.001) and total weight gain (AUC 0.615, cutoff 14.0 kg, P<0.001).
  
  
  CONCLUSIONS
  Cigarette smoking and weight gain control are relatively modifiable factors for which interventional management is necessary to avoid perinatal problems arising from SGA pregnancy. Further studies are needed to investigate optimal nutrition, health guidance and subsequent weight gain control that lead to concrete improvement in maternal and infant prognoses.
authors.affiliation: Department of Obstetrics and Gynaecology, Japanese Red Cross Katsushika Maternity Hospital, Tokyo, Japan. inde@nms.ac.jp
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Inde
authors.forename: Misao
authors.initials: M
authors.lastname: Satomi
authors.forename: Nao
authors.initials: N
authors.lastname: Iwasaki
authors.forename: Shuichi
authors.initials: S
authors.lastname: Ono
authors.forename: Eriko
authors.initials: E
authors.lastname: Yamashita
authors.forename: Miwa
authors.initials: M
authors.lastname: Igarashi
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Hiraizumi
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Murata
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Miyake
authors.forename: Shunji
authors.initials: S
authors.lastname: Suzuki
mesh_terms: D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D007564:Japan / Q000453:epidemiology; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D014427:Twins