Is there a residual risk of large-for-gestational-age infant related to gestational diabetes mellitus when it is treated?

Abstract

Objective: The hyperglycaemia and adverse pregnancy outcomes (HAPO) study, where hyperglycaemia was untreated, showed a continuous association between large-for-gestational-age (LGA) infant and seven increasing categories of fasting plasma glucose (PG), 1-hour and 2-hour PG values after a 75 g oral glucose tolerance test at 24-32 gestational weeks. We evaluated whether the excess risk persisted in the 6th and 7th glucose categories - corresponding to women treated for gestational diabetes mellitus (GDM).

Patients and methods: We included 7,190 women meeting the HAPO criteria, of whom 655 (9.2%) were treated for GDM (dietary education in all; insulin therapy in 150 (20.3%)). We evaluated the adjusted odds ratio (aOR) for each glucose category (reference 1st category) for LGA infant.

Results: The aOR for LGA linearly increased from the 1st to 5th categories of fasting, 1-hour and 2-hour PG. Specifically, the aORs for the 5th category were 2.20 (95% confidence interval 1.41-3.44), 2.25 (1.11-4.59), and 2.51 (1.63-3.85), respectively. The aORs for the 6th category were globally stable at 2.52 (1.46-4.36), 2.87 (1.48-5.54), and 2.47 (1.46-4.16), respectively. The same was true for the 7th category: 1.41 (0.56-3.55), 2.84 (1.03-7.86), and 3.53 (1.77-7.06), respectively.

Conclusion: We confirmed the association between increasing PG category and LGA infant in women without GDM. We did not observe a residual risk of LGA infant in women treated for GDM in our hospital, irrespective of elevated fasting, 1-hour, or 2-hour PG diagnosis. The risk of LGA infant was globally similar to that in women with high normal glucose values.

Keywords: gestational diabetes mellitus; hyperglycaemia and adverse pregnancy outcomes (HAPO) study; oral glucose tolerance test; pregnancy outcomes.