Gestational diabetic patients with adequate management have normal cardiovascular autonomic regulation during the third trimester of pregnancy and 3 months after delivery

Heart Rate Variability and Pregnancy Complications: Systematic Review

BACKGROUND

The autonomic nervous system (ANS) is known as a critical regulatory system for pregnancy-induced adaptations. If it fails to function, life-threatening pregnancy complications could occur. Hence, understanding and monitoring the underlying mechanism of action for these complications are necessary.

OBJECTIVE

We aimed to systematically review the literature concerned with the associations between heart rate variability (HRV), as an ANS biomarker, and pregnancy complications.

METHODS

We performed a comprehensive search in the PubMed, Medline Completion, CINAHL Completion, Web of Science Core Collection Classic, Cochrane Library, and SCOPUS databases in February 2022 with no time span limitation. We included studies concerned with the association between any pregnancy complications and HRV, with or without a control group. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline was used for the review of the studies, and Covidence software was used for the study selection process. For data synthesis, we used the guideline by Popay et al.

RESULTS

Finally, 12 studies with 6656 participants were included. Despite the methodological divergency that hindered a comprehensive comparison, our findings suggest that ANS is linked with some common pregnancy complications including fetal growth. However, existing studies do not support an association between ANS and gestational diabetes mellitus. Studies that linked pulmonary and central nervous system disorders with ANS function did not provide enough evidence to draw conclusions.

CONCLUSIONS

This review highlights the importance of understanding and monitoring the underlying mechanism of ANS in pregnancy-induced adaptations and the need for further research with robust methodology in this area.

Impaired vagal adaptation to an exercise task in women with gestational diabetes mellitus versus women with uncomplicated pregnancies

PURPOSE

Gestational diabetes mellitus (GDM) is associated with an increased risk for maternal and fetal complications. Patients with GDM have an increased cardiovascular risk in later life. The aim of this study was to investigate cardiac autonomic nervous system (ANS) function at rest and during exercise in women with GDM vs. women with uncomplicated pregnancies.

METHODS

Thirty-six normotensive pregnant women (21 with GDM and 15 age- and parity-matched women with an uncomplicated pregnancy) were enrolled in this case-control study. Continuous beat-by-beat blood pressure (BP) measurements were recorded during rest, intermittent handgrip exercise, and recovery (via photoplethysmography, Finapres®). Heart rate variability (HRV) (Kubios®) was used for the assessment of autonomic nervous system function.

RESULTS

The groups were similar in age, gestational week, and handgrip strength. At rest, no differences in HRV indices [root mean square of successive differences (RMSSD), standard deviation Poincaré plot 1, and 2 (SD1, SD2), SD2/SD1 ratio] were detected between women with GDM and women with an uncomplicated pregnancy. However, during exercise, a different pattern in the HRV responses was detected: in the control group, RMSSD and SD1 (indices of parasympathetic function) significantly decreased (p < 0.001) during handgrip exercise and returned to baseline during recovery. In contrast, in GDM, the above HRV indices remained unaltered throughout the protocol.

CONCLUSION

Normotensive women with GDM present impaired parasympathetic system ability to adapt to an exercise stimulus, as suggested by the blunted sensitivity in RMSSD and SD1. This finding suggests early alterations in ANS may exist in women with GDM, even when no differences are detected in resting conditions.

Sympathetic nervous system activity and reactivity in women with gestational diabetes mellitus

INTRODUCTION

Gestational diabetes mellitus (GDM) is associated with vascular dysfunction. Sympathetic nervous system activity (SNA) is an important regulator of vascular function, and is influenced by glucose and insulin. The association between GDM and SNA (re)activity is unknown. We hypothesize that women with GDM would have increased SNA during baseline and during stress.

METHODS

Eighteen women with GDM and 18 normoglycemic pregnant women (controls) were recruited. Muscle SNA (MSNA; peroneal microneurography) was assessed at rest, during a cold pressor test (CPT) and during peripheral chemoreflex deactivation (hyperoxia). Spontaneous sympathetic baroreflex gain was quantified versus diastolic pressure at rest and during hyperoxia.

RESULTS

Age, gestational age (third trimester) and pre-pregnancy body mass index and baseline MSNA was not different among the groups. Women with GDM had a similar increase in MSNA, but a greater pressor response to CPT compared to controls (% change in MAP 17 ± 7% vs. 9 ± 9%; p = .004). These data are consistent with a greater neurovascular transduction in GDM (% change in total peripheral resistance/% change in burst frequency [BF]: 15.9 ± 30.2 vs. -5.2 ± 16.4, p = .03). Interestingly, women with GDM had a greater reduction in MSNA during hyperoxia (% change in BF -30 ± 19% vs. -6 ± 17%; p = .01).

CONCLUSION

Women diagnosed with GDM have similar basal SNA versus normoglycemic pregnant women, but greater neurovascular transduction, meaning a greater influence of the sympathetic nerve activity in these women. We also document evidence of chemoreceptor hyperactivity, which may influence SNA in women with GDM but not in controls.

Effects of maternity yoga on the autonomic nervous system during pregnancy

AIM

To elucidate the changes in the daily variation seen in the autonomic nervous system during pregnancy brought about by maternity yoga and to evaluate how maternal yoga affects stress and sleep.

METHODS

A prospective, longitudinal study was conducted between January 2013 and December 2014. Pregnant women who were attending maternity yoga classes at Palmore Hospital between 20 and 23 weeks' gestation were enrolled as the yoga group, and a matched control group was also enrolled. Study participants completed questionnaires, including a perceived stress scale and sleep logs, during their second and third trimesters. Heart rate variability and salivary α-amylase levels were evaluated as stress indices at 20-23 weeks' gestation, 28-31 weeks' gestation and 36-40 weeks' gestation.

RESULTS

A total of 38 women were in the yoga group, with 53 in the control group. At 28-31 weeks' gestation, heart rate variability during night and late-night periods was significantly higher in the yoga group than in the control group. At 36-40 weeks' gestation, variability between the morning, afternoon and late night was significantly higher in the yoga group. Salivary α-amylase levels decreased significantly immediately after practicing yoga during all evaluation periods in the yoga group. Night-time sleep duration was significantly longer in the yoga group.

CONCLUSION

Our results suggest that practicing yoga activates the parasympathetic nervous system during the third trimester of pregnancy, consolidating sleep during the night and decreasing α-amylase levels, which indicates reduced stress.

Electrocardiographic Changes in Diabetes Mellitus

Diabetes mellitus (DM) has been known for many years to be associated with poor cardiovascular prognosis. Due to the sensitive neuropathy, the coronary artery disease in diabetic patients is frequently asymptomatic. Also twelve leads resting ECG can be within normal limits even in an advanced stage of coronary artery disease. Therefore in addition to the standard ECG other electrocardiographic procedures started to be studied in order to find some typical signs of myocardial damages caused by DM. Repeatedly reported results showed in DM patients without cardiovascular complications the tachycardia, shortening of the QRS and QT intervals, increase of the dispersion of QT interval, decreased amplitudes of depolarization waves, shortened activation time of ventricular myocardium and a flattening of T waves confirmed by the lower value of maximum and minimum in repolarization body surface isopotential maps. Most of these changes are even more pronounced in patients with cardiac autonomic neuropathy. Comparison with similar ECG changes in other diseases suggests that the electrocardiographic changes in DM patients are not specific and that they are particularly caused by an increased tone of the sympathetic nervous system what was indirectly confirmed by the heart rate variability findings in these patients.

ECG Body Surface Mapping in Patients With Gestational Diabetes Mellitus and Optimal Metabolic Compensation

Women with gestational diabetes mellitus (GDM) are at increased risk for cardiovascular diseases (CVD) events compared with women without GDM. The aim of the present study was to evaluate 200 parameters of the heart electric field in 35 women with GDM under optimal glycemic compensation compared to 32 healthy pregnant women. All examinations were performed in the 36th week of gestation. The parameters in ECG body surface mapping (BSM) were registered by the diagnostic system Cardiag 112.2. The absolute values of maximum and minimum in depolarization and repolarization isopotential, isointegral and isoarea maps were not significantly different between the groups. These findings correspond to the result of heart rate variability examination. However BSM revealed the significant prolongation of QRS complex (p=0.05), shortening of ventricular myocardial activation time (ICHVAT) (p=0.01), prolongation of mean QT duration (p=0.01) and increase of QT interval dispersion (p=0.01) in women with GDM. Duration of QRS and ICHVAT significantly correlated with interventricular septum and posterior wall thickness in GDM group, QTd interval correlated significantly with HbA1C level. We conclude that despite of optimal metabolic control several significant abnormalities detected by ECG BSM are still present in patients with GDM.

Autonomic modulation in gestational diabetes mellitus

AIMS

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Growth factors in preeclampsia: a vascular disease model. A failed vasodilation and angiogenic challenge from pregnancy onwards?

Preeclampsia is the major cause of maternofetal and neonatal morbi-mortality including intrauterine growth retardation, miscarriages and stillbirths. Inadequate vascular dilation and angiogenesis represent the crucial underlying defect of gravidic hypertension, denoting a failed response to the vasodilatory and pro-angiogenic challenge imposed by pregnancy, especially if multifetal. A similar pathogenesis appears involved in gestational diabetes. In this review we aimed to provide a hint on understanding the deeply involved angiogenic disorders which eventually culminate in utero-placental failure. The key players in these complex processes may be found in an intricate network of growth factors (GFs) and GF inhibitors, controlled by several vascular risk factors modulated by environment and genes, which eventually impact on early and late cardiovascular outcomes of mother and fetus.

Metabolic Profile of Offspring from Diabetic Wistar Rats Treated with Mentha piperita (Peppermint)

This study aimed at evaluating glycemia and lipid profile of offspring from diabetic Wistar rats treated with Mentha piperita (peppermint) juice. Male offspring from nondiabetic dams (control group: 10 animals treated with water and 10 treated with peppermint juice) and from dams with streptozotocin-induced severe diabetes (diabetic group: 10 animals treated with water and 10 treated with peppermint juice) were used. They were treated during 30 days, and, after the treatment period, levels of glycemia, triglycerides, total cholesterol, and fractions were analyzed in the adult phase. The offspring from diabetic dams treated with peppermint showed significantly reduced levels of glucose, cholesterol, LDL-c, and triglycerides and significant increase in HDL-c levels. The use of the M. piperita juice has potential as culturally appropriate strategy to aid in the prevention of DM, dyslipidemia, and its complications.