Maternal C-peptide may offer clues to fetal condition
medwireNews: The appearance of C-peptide during pregnancy in women with type 1 diabetes and previously undetectable levels may indicate fetal hyperinsulinism and the opportunity to intervene, say researchers.
Claire Meek (University of Cambridge, UK) and colleagues measured C-peptide levels in the serum samples of 127 pregnant women with type 1 diabetes who participated in the CONCEPTT trial.
The majority (58.3%) of these women had undetectable C-peptide at all three timepoints (12, 24, and 34 weeks’ gestation), the team reports in Diabetes Care.
An additional 24.4% had detectable levels from week 34, although these were on average considerably lower than levels in the 17.3% of women who had detectable C-peptide throughout pregnancy, at 8.8 versus 47.0 pmol/L.
Women with detectable C-peptide from week 34 spent more time in hyperglycemia in week 24 than those in the other two groups, and they had a “striking” rate of babies who were large for their gestational age, at 90.3% compared with 59.5% in women with undetectable C-peptide throughout pregnancy.
Their babies also had significantly higher rates of neonatal hypoglycemia (41.9 vs 13.5%), respiratory distress (12.9 vs 2.7%), and admission to the neonatal intensive care unit (45.2 vs 23.0%). Moreover, for a subset with cord blood measurements, C-peptide was present at significantly higher levels, at a geometric mean of 1319 versus 718 pmol/L.
Given its association with “neonatal complications related to hyperinsulinism,” the researchers believe the C-peptide appearing in maternal serum at week 34 is “likely of fetal origin,” and may explain previous reports of increased C-peptide production during pregnancy in women with type 1 diabetes.
They add: “It is also possible that this process occurred in some women with detectable C-peptide throughout pregnancy.”
Meek and team say that direct measurement of fetal hyperinsulinism in clinical practice is not possible, but suggest that monitoring increases in maternal C-peptide “could provide an opportunity for more precise monitoring of the hyperinsulinemic fetus” and prediction of complications.
They say that if maternal C-peptide can significantly enhance the predictive ability of time in target blood glucose range, then it could facilitate the timely delivery of interventions such as automated insulin delivery and improved delivery planning, or even “prophylaxis with buccal mucosal glucogel to prevent neonatal hypoglycemia.”
The researchers also presented their findings at the virtual ADA 81st Scientific Sessions.
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