title: Pregestational diabetes is associated with adverse outcomes in twin pregnancies: a regional register-based study.
abstract: BACKGROUND
  The incidence of pregnancies complicated by twinning and diabetes is increasing in the UK. This is a worrying trend as both diabetes and twin gestations are associated with a high risk of adverse pregnancy outcomes. The few studies that have specifically addressed how twinning and pregestational diabetes in the same pregnancy may affect outcome have reported conflicting results.
  
  
  METHODS
  We analyzed data on 27 women with a twin pregnancy and pregestational diabetes (54 babies) and 6407 women with a twin pregnancy without diabetes (12 814 babies) from the Northern Survey of Twin and Multiple Pregnancy during 1998-2010. A composite adverse pregnancy outcome (comprising fetal loss before 24 weeks, termination of pregnancy, stillbirth, infant death or any major congenital anomaly), extended perinatal mortality (stillbirths and neonatal deaths) and major congenital anomaly were the main outcome measures. Adjusted rate ratios were estimated using generalized estimating equations for Poisson regression controlling for potential confounders.
  
  
  RESULTS
  Mothers with twin pregnancies with diabetes were older (p = 0.001) and had higher body mass indices (p < 0.0001) than those without diabetes. Their twins were more likely to be delivered earlier (p = 0.026), be delivered by cesarean section (80.4% vs. 49.7%; p < 0.0001), be large-for-gestational-age (p < 0.0001) and require admission to a special care baby unit (p < 0.0001). Pregestational diabetes was associated with significantly increased rates of the composite adverse outcome and major congenital anomalies in twins (adjusted rate ratios 2.66, 95% confidence interval 1.14-6.20 and adjusted rate ratios 3.51, 95% confidence interval 1.31-9.40, respectively).
  
  
  CONCLUSIONS
  Maternal pregestational diabetes in twin pregnancies is associated with a significantly increased risk of an adverse pregnancy outcome.
authors.affiliation: Institute of Health & Society, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Joanne
authors.identifier: http://orcid.org/0000-0003-3718-4889
authors.initials: J
authors.lastname: Darke
authors.affiliation: Institute of Health & Society, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Svetlana V
authors.identifier: http://orcid.org/0000-0001-6690-4975
authors.initials: SV
authors.lastname: Glinianaia
authors.affiliation: Department of Obstetrics and Gynaecology, Newcastle Hospitals NHS Foundation Trust, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
authors.forename: Philippa
authors.identifier: http://orcid.org/0000-0002-6555-0893
authors.initials: P
authors.lastname: Marsden
authors.affiliation: Institute of Health & Society, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Ruth
authors.identifier: http://orcid.org/0000-0002-8464-8933
authors.initials: R
authors.lastname: Bell
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002585:Cesarean Section; D000013:Congenital Abnormalities / Q000453:epidemiology*; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology; D005260:Female; D005320:Fetal Macrosomia / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D008297:Male; D008423:Maternal Age; D054238:Perinatal Mortality; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000453:epidemiology*; D018566:Pregnancy, High-Risk; D059285:Pregnancy, Twin / Q000706:statistics & numerical data*; D012042:Registries; D050497:Stillbirth / Q000453:epidemiology*; D006113:United Kingdom / Q000453:epidemiology
keywords: Diabetes mellitus; perinatal outcomes; pregestational diabetes mellitus; twin pregnancy; twins; type 1 diabetes; type 2 diabetes