Seasonal variations in incidence and maternal–fetal outcomes of gestational diabetes. Issue 4 (5th February 2020)

• Record Type: Journal Article
• Authors: Meek, C. L.; Devoy, B.; Simmons, D.; Patient, C. J.; Aiken, A. R.; Murphy, H. R.; Aiken, C. E.
• Is Part Of: Diabetic medicine. Volume 37:Issue 4(2020)
• Page Start: 674
• Page End: 680
• Publication Date: 2020-02-05
• Subjects: Diabetes -- Periodicals; 616.462
• DOI: 10.1111/dme.14236
• Languages: English
• ISSNs: 0742-3071

Abstract

Abstract: Aims: To determine whether the neonatal and delivery outcomes of gestational diabetes vary seasonally in the context of a relatively cool temperate climate. Methods: A retrospect cohort of 23 735 women consecutively delivering singleton, live‐born term infants in a single tertiary obstetrics centre in the UK (2004–2008) was identified. A total of 985 (4.1%) met the diagnostic criteria for gestational diabetes. Additive dynamic regression models, adjusted for maternal age, BMI, parity and ethnicity, were used to compare gestational diabetes incidence and outcomes over annual cycles. Outcomes included: random plasma glucose at booking; gestational diabetes diagnosis; birth weight centile; and delivery mode. Results: The incidence of gestational diabetes varied by 30% from peak incidence (October births) to lowest incidence (March births; P =0.031). Ambient temperature at time of testing (28 weeks) was strongly positively associated with diagnosis ( P <0.001). Significant seasonal variation was evident in birth weight in gestational diabetes‐affected pregnancies (average 54 th centile June to September; average 60 th centile December to March; P =0.027). Emergency Caesarean rates also showed significant seasonal variation of up to 50% ( P =0.038), which was closely temporally correlated with increased birth weights. Conclusions: There is substantial seasonal variation in gestational diabetes incidence and maternal–fetal outcomes, even in a relatively cool temperate climate. The highest average birth weight and greatest risk of emergency Caesarean delivery occurs in women delivering during the spring months. Recognizing seasonal variation in neonatal and delivery outcomes provides new opportunity for individualizing approaches to managing gestational diabetes. What's new?: Gestational diabetes (GDM) shows seasonal variation in hot climates, but there is no consensus on whether this impacts on neonatal or delivery outcomes. Birth weights and emergency Caesarean section rates vary seasonally in GDM‐affected pregnancies. The highest average birth weight and greatest risk of emergency Caesarean delivery occur when fewest births are complicated by GDM (March births). There are seasonal differences in GDM outcomes, and consideration should be given to the differing environmental, dietary and lifestyle factors faced by women with GDM throughout the year.