title: Pregnancy outcomes among women with beta-thalassemia trait.
abstract: OBJECTIVE
  To compare the obstetric outcomes between pregnant women affected by beta-thalassemia trait and normal controls.
  
  
  METHODS
  A retrospective cohort study was conducted on singleton pregnant women complicated by beta-thalassemia trait and normal controls, randomly selected with the controls-to-case ratio of 2:1. All were low-risk pregnancies without underlying medical diseases and fetal anomalies. The pregnancies undergoing invasive prenatal diagnosis were excluded.
  
  
  RESULTS
  A total of 597 pregnant women with beta-thalassemia trait and 1194 controls were recruited. Baseline characteristics and maternal outcomes in the two groups were similar, except that hemoglobin levels were slightly lower in the study group. The prevalence of small for gestational age and preterm birth tended to be higher in the study group but not reached the significant levels but the rate of low birth weight was significantly higher in the study group (relative risk 1.25; 95 % CI 1.00-1.57). Additionally, abortion rate was also significantly higher in the study group (relative risk 3.25; 95 % CI 1.35-7.80).
  
  
  CONCLUSIONS
  Beta-thalassemia trait could minimally, but significantly, increase risk of low birth weight but did not increase rates of maternal adverse outcomes.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Chitrakan
authors.initials: C
authors.lastname: Charoenboon
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Phudit
authors.initials: P
authors.lastname: Jatavan
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Kuntharee
authors.initials: K
authors.lastname: Traisrisilp
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand. ttongson@mail.med.cmu.ac.th.
authors.forename: Theera
authors.initials: T
authors.lastname: Tongsong
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology* / Q000209:etiology; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000453:epidemiology*; D011256:Pregnancy Outcome / Q000453:epidemiology*; D047928:Premature Birth / Q000453:epidemiology / Q000209:etiology; D011296:Prenatal Diagnosis / Q000009:adverse effects; D012189:Retrospective Studies; D013785:Thailand / Q000453:epidemiology; D017086:beta-Thalassemia / Q000097:blood / Q000150:complications* / Q000453:epidemiology
keywords: Beta-thalassemia; Outcomes; Pregnancy; Trait