title: Pregnancy outcomes before and after institution of a specialised twins clinic: a retrospective cohort study.
abstract: BACKGROUND
  Although specialised clinics for multiple pregnancies are recommended by several Obstetrics and Gynaecology governing bodies, studies examining outcome before and after introduction of such clinics remain few, were performed predominantly in North America in the 1990s, and either amongst dichorionic twin pregnancies only or where chorionicity was not specified. Our objective, in the modern setting with twins of known chorionicity, was to compare maternal and neonatal outcomes of twin pregnancies before and after commencement of a consultant-led, multidisciplinary twins clinic (TC).
  
  
  METHODS
  Retrospective cohort study of 513 women, with birth of twins at ≥20 weeks' gestation, January 2007 to November 2011, at a metropolitan tertiary maternity hospital, Sydney, Australia. Demographic, pregnancy, and outcome data were obtained from hospital databases. Women receiving TC care (2009-2011) were compared to those receiving general antenatal clinic (ANC) care (2007-2010) and private care (2009-2011). Other models of care were excluded. Main outcome measures were total maternal inpatient stay, mode of birth, gestational age at birth, and neonatal nursery admission.
  
  
  RESULTS
  286 women were included in the main analyses: 84 attended ANC, 101 TC, and 101 a private obstetrician. TC women had similar demographics to ANC women and were slightly younger than private patients. TC women had lower Caesarean section rates (55% vs. 70% ANC and 76% private, p = 0.008) and fewer late preterm (34 + 0-36 + 6 weeks) births, (26%TC vs. 44% ANC and 41% private, p < 0.001). Median maternal inpatient stay was shorter in TC than ANC (7 vs. 8 days, p = 0.009) and similar to private (7 days). Nursery admission rates were higher in private patients (67% vs. 49% ANC and 47% TC, p = 0.001) and average birthweight lower (2283 g vs. 2501 g ANC and 2496 g TC, p < 0.001).
  
  
  CONCLUSIONS
  Within a single centre, maternal and neonatal twin pregnancy outcomes varied significantly by model of care. Introducing a specialised twins clinic in our setting decreased Caesarean section rates, late preterm birth, and inpatient stay compared to ANC.
authors.affiliation: School of Women's and Children's Health, UNSW Medicine, Kensington, NSW, Australia. Amanda.Henry@unsw.edu.au.|Department of Maternal-Fetal Medicine, Royal Hospital for Women, Sydney, NSW, Australia. Amanda.Henry@unsw.edu.au.
authors.forename: Amanda
authors.initials: A
authors.lastname: Henry
authors.affiliation: Department of Maternal-Fetal Medicine, Royal Hospital for Women, Sydney, NSW, Australia. niclees@gmail.com.
authors.forename: Nicole
authors.initials: N
authors.lastname: Lees
authors.affiliation: Department of Emergency Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia. kendall.bein@sswahs.nsw.gov.au.
authors.forename: Kendall J
authors.initials: KJ
authors.lastname: Bein
authors.affiliation: Midwifery and Women's Health Nursing Research Unit, University of Sydney, Sydney, Australia. beverley.hall@sesiahs.health.nsw.gov.au.
authors.forename: Beverley
authors.initials: B
authors.lastname: Hall
authors.affiliation: School of Women's and Children's Health, UNSW Medicine, Kensington, NSW, Australia. veronica.lim@sesiahs.health.nsw.gov.au.
authors.forename: Veronica
authors.initials: V
authors.lastname: Lim
authors.affiliation: School of Women's and Children's Health, UNSW Medicine, Kensington, NSW, Australia. Katie.qiao.chen@gmail.com.
authors.forename: Katie Qiao
authors.initials: KQ
authors.lastname: Chen
authors.affiliation: School of Women's and Children's Health, UNSW Medicine, Kensington, NSW, Australia. Alec.Welsh@unsw.edu.au.|Department of Maternal-Fetal Medicine, Royal Hospital for Women, Sydney, NSW, Australia. Alec.Welsh@unsw.edu.au.
authors.forename: Alec W
authors.initials: AW
authors.lastname: Welsh
authors.affiliation: Department of Perinatal Medicine, Mercy Hospital for Women, Heidelberg, VIC, Australia. lhui@mercy.com.au.|Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Australia. lhui@mercy.com.au.
authors.forename: Lisa
authors.initials: L
authors.lastname: Hui
authors.affiliation: School of Women's and Children's Health, UNSW Medicine, Kensington, NSW, Australia. Antonia.Shand@sesiahs.health.nsw.gov.au.|Department of Maternal-Fetal Medicine, Royal Hospital for Women, Sydney, NSW, Australia. Antonia.Shand@sesiahs.health.nsw.gov.au.
authors.forename: Antonia W
authors.initials: AW
authors.lastname: Shand
mesh_terms: D000328:Adult; D005260:Female; D005865:Gestational Age; D006760:Hospitalization / Q000706:statistics & numerical data; D006771:Hospitals, Maternity / Q000706:statistics & numerical data*; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D009517:New South Wales; D011247:Pregnancy; D011256:Pregnancy Outcome; D059285:Pregnancy, Twin / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D062606:Tertiary Care Centers / Q000706:statistics & numerical data*; D014427:Twins