Birthweight of Babies Born to Mothers with Type 1 Diabetes: is it Related to Blood Glucose Control in the First Trimester?

Abstract

A retrospective study of 133 pregnancies in women with Type 1 diabetes was performed, and the 116 which progressed beyond 28 weeks were further analysed. Despite good maternal blood glucose control (mean (+/- SE) HbA1 levels 8.6 +/- 0.2% at the end of the first trimester; 6.9 +/- 0.2% at delivery; normal range 4.0-8.5%), 38% of babies had birthweights above the 90th centile and operative intervention occurred in 77 deliveries (66%). There was no significant correlation between birthweight and HbA1 level at any stage of pregnancy, but mothers with babies above the 90th centile for weight had a higher HbA1 at the end of the first trimester than mothers with babies below the 90th centile (9.3 +/- 0.5 vs 7.9 +/- 0.2%, p less than 0.05). In contrast there was no difference in the HbA1 levels at delivery (7.0 +/- 0.3 vs 6.8 +/- 0.2%). The perinatal mortality rate was 17.7 per 1000 births. The results confirm that in Type 1 diabetes large babies are common despite good blood glucose control, and suggest that maternal blood glucose control in the first trimester may be an important determinant of birthweight.

Maternal glucose levels influence birthweight and ‘catch‐up’ and ‘catch‐down’ growth in a large contemporary cohort

“…Even with maternal glucose levels in the normal range, the higher the ambient glucose during the last trimester of pregnancy, the heavier the baby at birth. These results are consistent with data from other populations, in mothers who have pre‐existing diabetes [8–14] and with all the studies of maternal glucose levels and fetal growth in non‐diabetic populations [16–18].…”

Etiology, Detection, and Management of Fetal Macrosomia in Pregnancies Complicated by Diabetes Mellitus

“…[14][15][16][17] There is, however, no agreement about which maternal glucose measure temporally related to meals is a better predictor of macrosomia. Although some [15][16][17][18][19] have found that the postmeal glucose and/or hemoglobin A1 are the best predictors, others 14 have reported that a fasting glucose taken from 29 to 32 weeks is a better predictor than postprandial measures.…”

Macrosomia despite good glycaemic control in Type I diabetic pregnancy; results of a nationwide study in The Netherlands

“…However, despite improved glycaemic control over the past decade, the incidence of macrosomia is still very high (27-43%) and does not seem to decline [1,4,5,14,15,16,17]. When trying to reduce macrosomia in Type I diabetic pregnancies, it would be useful to know the characteristics of women with the highest risk for having a macrosomic infant.…”