T1D and pregnancy: preterm birth risk is strongly linked to periconception HbA1c

  • Ludvigsson JF & al.
  • Ann Intern Med
  • 23 Apr 2019

  • International Clinical Digest
Access to the full content of this site is available only to registered healthcare professionals. Access to the full content of this site is available only to registered healthcare professionals.

Takeaway

  • Preterm birth risk was strongly linked to periconceptional HbA1c levels among women with type 1 diabetes (T1D), and excess risk was seen even within the recommended range.

Why this matters

  • The relationship between maternal glycemic control and preterm birth has been unclear.

Study design

  • Swedish population-based cohort study of 2474 singleton infants born to women with T1D and 1,165,216 infants born to 746,916 women without T1D.
  • Funding: Swedish Diabetes Foundation.

Key results

  • Preterm birth (
  • Preterm birth incidence:
    • HbA1c
    • HbA1c 6.5%-7.7%: 20.6%. 
    • HbA1c 7.8%-9.1%: 28.3%.
    • HbA1c >9.1%: 37.5%.  
  • Adjusted risk ratios (aRRs; 95% CIs) for preterm birth in T1D vs non-T1D, by HbA1c:
    • 6.5%-7.7%: 4.22 (3.74-4.75); 
    • 7.8%-9.1%: 5.56 (4.84-6.38); and
    • >9.1%: 6.91 (5.85-8.17).
  • With HbA1c cutoff lowered to
  • Higher HbA1c levels were associated with secondary outcomes of large for gestational age, hypoglycemia, respiratory distress, Apgar score

Limitations

  • Possible residual confounding.
  • HbA1c values not available for all patients with T1D.
  • No data on physical activity, drinking habits, or race/ethnicity.
  • BMI based on self-reported height.  
  • All-Swedish population.