Are conventional targets for metabolic control sufficient to prevent fetal macrosomia during diabetic pregnancy?

We report the case of a 26 year-old woman, with an uncomplicated type 1 IDDM of 17 yr duration followed for her first pregnancy. At conception, HbA1c (measured by HPLC) was 6.5% and fructosamine was 280 u.mol.l (normal range below 285). During the follow-up, 15-days-interval frutosamine never exceeded the normal range and HbA1c values were under 6.5% excepted in the third trimester (7.0 +/- 0.8%) coinciding with a bad control of the 2 hours post-prandial blood glucose. A fetal macrosomy was discovered at 34 weeks of gestation and a heavy-for-date 4680 g baby was delivered by caesarean section at 38 weeks of gestation. Our case report outlines again the need to achieve the recommended target of metabolic control for the diabetic pregnant woman (blood preprandial glucose: 3.9-5.6 mM; post-prandial 2 h < 6.7 mM) specially during the third trimester of pregnancy. The use of computer databases might be helpful for precise monitoring during this narrow window period.