Pregnancy and type 1 diabetes

A study of pregnancy-related outcomes for U.S. women with type 1 diabetes conducted by HMS researchers at Joslin Diabetes Center found that during a recent 13-year period the percentage of mothers with excess weight gain during pregnancy increased by 10 percent, A1c levels remained steady, and the prevalence of nephropathy fell from 4.8 percent to zero. In addition, analysis of the data showed that during the period studied, the use of insulin pumps increased by about 23 percent while the use of continuous glucose monitoring went from zero in the first years to nearly 40 percent during the last years of the study.

The research team began its investigation to understand why women with type 1 diabetes have large birth-weight babies and to determine whether the prevalence of babies born very large had changed over the years. To suss out this relationship, the investigators also needed to understand the influence that a broad number of variables, such as treatment, delivery, and neonatal health, as well as the mothers’ glucose levels, gestational weight gain, and other maternal factors, have on pregnancy outcomes.

The researchers drew their data from medical records of 700 pregnant women with type 1 diabetes who attended the Joslin Diabetes Center and Beth Israel Deaconess Medical Center Diabetes in Pregnancy Program between 2004 and 2017.

In addition to describing trends in pregnancy-related outcomes for women with type 1 diabetes, the study showed that length of pregnancy increased slightly over time and that the prevalence of babies born very large remained high throughout the study period. The latter finding is concerning because large babies are at greater risk for metabolic diseases in later life.

Helman S et al., Journal of Perinatology, June 2020