Deleterious effects of hyperglycemia on fetal outcome

Combined incidence of major congenital anomalies and spontaneous abortion according to the hemoglobin A1 (HbA1) value during the first trimester of pregnancy in 303 pregnant individuals with type 1 diabetes. The risk rose markedly at HbA1 values above 11% (approximately equivalent to a contemporary A1C value of 8.5%). Other studies have found an increase in risk at A1C values above 9.5%.