Autonomic modulation in gestational diabetes mellitus

The aim of this study was to evaluate the influence of gestational diabetes mellitus (GDM) and positional aortocaval compression on cardiovascular autonomic nervous system (ANS) function in late pregnancy.

Pregnant women with (n=31) and without (n=12) GDM were evaluated at 30-35weeks gestation and 2-3months postpartum. Measures of ANS function included power spectral analysis (performed sitting) and RR-variation during deep breathing (performed supine). Time-related changes (late pregnancy versus 2-3months postpartum) for measurements of cardiovascular ANS function were analyzed using multivariate analysis of variance for repeated measures.

Baseline characteristics were similar for both groups. Comparing ANS measures for GDM+versus GDM- women during pregnancy and postpartum revealed no significant differences. Time related changes indicated that during late pregnancy total spectral power, low frequency (LF) power, high frequency (HF) power, and RR-variation during deep breathing were significantly reduced (p<0.001 for all). The LF/HF ratio, however, was not significantly affected during late pregnancy (p=0.678).

Our results suggest decreased activity in both branches of the ANS during mid-third trimester pregnancy, but no significant change in sympathovagal balance. Aortocaval compression appears to affect ANS function whether tests were performed sitting or supine for GDM+and GDM- women.