Normal glucose levels in pregnancy may run low.(Obstetrics)

PRAGUE -- Normative values for mean blood glucose levels during the first trimester may be much lower than what has been reported previously, Dr. Yariv Yogev reported at the 20th European Congress of Perinatal Medicine.

This lower-than-expected glycemic profile may suggest new targets for glycemic control during pregnancy complicated by diabetes, said Dr. Yogev of the department of obstetrics and gynecology at Rabin Medical Center, Petah Tikva, Israel.

Before this study, there was little information on the definition of normal blood glucose levels during pregnancy, especially during the first trimester, he said. Most of the previous information had come from "very limited studies" of 10-25 patients, mostly in the third trimester, who were placed on a strict diet and hospitalized to evaluate their glycemic profile.

The current study included 62 healthy, nondiabetic women in their first trimester of pregnancy (average of 10 weeks' gestation). The investigators fit the women with continuous glucose monitoring devices that measured their blood glucose levels every 5 minutes for 72 hours.

Patients were asked not to modify their lifestyles or nutritional habits during the study.

The women's overall mean blood glucose (79.3 mg/dL) and mean fasting blood glucose levels (75 mg/dL) were "much, much lower than was previously reported by others."

Mean nighttime blood glucose levels (66 mg/dL) "almost represented hypoglycemia," but such values may actually represent "normal ...