Clinical Epidemiology (Jul 2021)

Glycemic Control in Pregnancies Complicated by Pre-Existing Diabetes Mellitus and Congenital Malformations: A Danish Population-Based Study

  • Arendt LH,
  • Pedersen LH,
  • Pedersen L,
  • Ovesen PG,
  • Henriksen TB,
  • Lindhard MS,
  • Olsen J,
  • Sørensen HT,
  • Ramlau-Hansen CH

Journal volume & issue
Vol. Volume 13
pp. 615 – 626

Abstract

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Linn Håkonsen Arendt,1– 3 Lars Henning Pedersen,1,4 Lars Pedersen,5 Per Glud Ovesen,1,6 Tine Brink Henriksen,7 Morten Søndergaard Lindhard,8 Jørn Olsen,2,5 Henrik Toft Sørensen,5 Cecilia Høst Ramlau-Hansen2 1Department of Obstetrics and Gynecology, Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark; 2Department of Public Health, Research Unit for Epidemiology, Aarhus University, Aarhus, Denmark; 3Department of Obstetrics and Gynecology, Regional Hospital Horsens, Horsens, Denmark; 4Department of Biomedicine, Aarhus University, Aarhus, Denmark; 5Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark; 6Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark; 7Department of Child and Adolescent Health, Aarhus University Hospital, Aarhus, Denmark; 8Department of Child and Adolescent Health, Regional Hospital Randers, Aarhus, DenmarkCorrespondence: Linn Håkonsen ArendtDepartment of Obstetrics and Gynecology, Aarhus University Hospital, Aarhus, Denmark; Department of Public Health, Research Unit for Epidemiology, Aarhus, DenmarkTel +45 27 21 09 81Email [email protected]: To study the occurrence of major congenital abnormalities in children of women with type 1 and type 2 diabetes and investigate the association between glycated haemoglobin (HbA1c) and major congenital malformations according to type 1 diabetes and type 2 diabetes separately.Patients and methods: In this register-based study, all singletons born alive from January 1, 2000 to December 31, 2015 in the North Denmark and Central Denmark regions of Denmark and their mothers were included. We used data from Danish health registers and the LABKA database. Logistic regression models were used to compute crude and adjusted prevalence odds ratios (cORs and aORs) with 95% confidence intervals (CIs) for major congenital malformations overall and for subtypes, by type of maternal pre-existing diabetes and HbA1c levels.Results: Among 314,245 infants included, 2020 (0.64%) had mothers with type 1 diabetes and 498 (0.16%) had mothers with type 2 diabetes. We found an aOR of 2.9 (95% CI: 2.5, 3.5) and 1.9 (95% CI: 1.3; 2.8) for major malformations for type 1 and type 2 diabetes, respectively. The highest occurrence was seen for major congenital heart diseases, but we also observed higher occurrence of several other non-cardiac malformations. For both type 1 and type 2 diabetes, the prevalence of major congenital malformations increased with higher levels of maternal HbA1c with no safe threshold level. Mothers with type 1 diabetes had higher risks than those without diabetes irrespective of HbA1c, and women with HbA1c levels ≥ 9.5% had 8 times the odds of major congenital malformations [aOR 8.7 (95% CI: 5.4; 14.5)].Conclusions: The prevalence of major congenital malformations progressively increased with poorer glycemic control during pregnancy, with no obvious safe threshold level, for both type 1 and type 2 diabetes.Keywords: congenital heart diseases, diabetes, epidemiology, malformations, pregnancy, register-based research

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