Aims To study the influence of the quantity and the quality of carbohydrate consumption on glycemic control in early pregnancy among women with type 1 diabetes. Methods A retrospective study of 107 women with type 1 diabetes who completed 1–3 days of diet recording before first antenatal visit, as a part of routine care. The total daily carbohydrate consumption from the major sources (e.g. bread, potatoes, rice, pasta, dairy products, fruits, candy) was calculated. A dietician estimated the overall glycemic index score (scale 0–7). Results At least two days of diet recording were available in 75% of the 107 women at mean 64 (SD ± 14) gestational days. The quantity of carbohydrate consumption from major sources was 180 (±51) g/day. HbA1c was positively associated with the quantity of carbohydrate consumption (β = 0.41; 95% CI 0.13–0.70, P = 0.005), corresponding to an increase of 0.4% in HbA1c per 100 g carbohydrates consumed daily, when adjusted for insulin dose/bodyweight and use of insulin pump treatment. The median (IQR) glycemic index score was 2 (0–3). An adjusted association between HbA1c and glycemic index score was not demonstrated. The women using carbohydrate counting daily (45%) had lower HbA1c compared to the remaining women (6.4 (±0.5) vs. 6.8 (±0.9)% (47 ± 6 vs. 51 ± 10 mmol/mol), P = 0.01). Conclusions HbA1c in early pregnancy was positively associated with the quantity of carbohydrate consumption regardless of insulin treatment. Carbohydrate counting is probably important for glycemic control in pregnant women with type 1 diabetes.