Fetal middle-cerebral and umbilical artery flow assessments after glucose challenge test

The effect of 50 GR oral glucose tolerance test on fetal celiac artery and superior mesenteric artery Doppler parameters in healthy pregnancies

OBJECTIVES

To understand the effect of 50-g oral glucose tolerance test (OGTT) on fetal celiac artery and superior mesenteric artery (SMA) Doppler parameters.

METHODS

A total of 43 healthy pregnant women followed in our hospital were included in the study. All Doppler parameters of the celiac artery and SMA (peak systolic velocity (PSV); pulsatility index (PI); resistance index (RI); systolic/diastolic ratio (SD); time average maximum velocity (TAMAX)) were obtained by ultrasonography before and 1 h after OGTT.

RESULTS

The mean PSV value of the celiac artery decreased statistically significantly after OGTT (37.29 ± 11.96 cm/s; 29.51 ± 10.07 cm/s; p=0.002). While the mean of the PI was 2.09 ± 0.57 before the test, it was found to be 1.84 ± 0.64 after the test (p=0.027). Mean PSV (39.82 ± 13.07 cm/s; 35.19 ± 15.27 cm/s; p=0.104) and PI (2.21 ± 0.65; 2.11 ± 0.80; p=0.375) values of SMA were also found to be decreased without statistically significancy.

CONCLUSIONS

The data obtained from our study reveals that the PSV and PI values of celiac artery and SMA slightly decrease after OGTT.

The effect of glucose tolerance test on fetoplacental circulation

OBJECTIVE

Acute hyperglycemia affects the fetoplacental circulation. This study aims to investigate the possible effect of acute hyperglycemia induced by 50 g oral glucose tolerance test (OGTT) on fetoplacental circulation in women between 24 and 28 weeks of gestation.

MATERIALS AND METHODS

Between January 2019 and April 2019, a total of 29 women who were between 24 and 28 weeks of gestation with a singleton gestation and were in low-risk group were included in this prospective study. All patients underwent fetal biometric measurements using ultrasonography (USG) and were administered 50 g OGTT. Before and 1 h after the test, Doppler USG was used to measure uterine artery, umbilical artery (UA), middle cerebral artery (MCA), pulsatility index (PI), resistance index (RI), and systolic/diastolic (S/D) ratio. The cerebroplacental ratio (CPR) was calculated as the ratio of the MCA-PI/UA-PI.

RESULTS

There was a decline in the MCA-RI (p = 0.008) and UA-PI (p = 0.021) at 1 h after the administration of 50 g OGTT. Z-scores of the mean UA-PI, MCA-PI, and CPR were calculated and a statistically significant increase in the Z-scores of the mean UA-PI was observed (p = 0.028).

CONCLUSION

Our study results show that acute hyperglycemia induced by OGTT significantly increases the Z-scores of the UA-PI, affecting the fetoplacental circulation.

The effect of 75-g oral glucose tolerance test on maternal and foetal Doppler parameters in healthy pregnancies: a cross-sectional observational study

Hyperglycaemia can alter placental resistance to blood flow and hyperglycaemia has adverse perinatal outcomes. Oral glucose tolerance testing (OGTT) increases the maternal plasma glucose levels temporarily and mimics metabolic hyperglycaemia. The blood flow of the uterine artery (UtA), umbilical artery (UA), middle cerebral artery (MCA) were assessed before, 1 and 2 h following the OGTT by using Doppler ultrasonography. Z-score of cerebroplacental ratio (CPR), pulsatility index (PI) for three vessels were evaluated separately. All measurements of the MCA, UA, UtA Doppler parameters were not statistically different for fasting, and 1 and 2 h following the 75 g OGTT in the 53 pregnant women with a singleton gestation in the low-risk group. This study results show that acute hyperglycaemia induced by OGTT has no effect on maternal and foetal Doppler parameters in healthy pregnancies.IMPACT STATEMENTWhat is already known on this subject? Foetal glucose is affected by maternal blood glucose concentrations and placental blood flow. Acute hyperglycaemia may have an effect on maternal, and foetal Doppler parameters among healthy pregnanciesWhat do the results of this study add? Our findings indicate that blood flow velocity metric measurements in the UA, MCA and UtA were not affected by the OGTT in healthy pregnant women.What are the implications of these findings for clinical practice and/or further research? Acute hyperglycaemia induced by OGTT does not have any effect on fetomaternal circulation, especially foetal brain blood flow. Other foetal vessels including ductus venosus, renal artery, etc. may be affected by maternal blood glucose levels during the OGTT or in diabetic patients. Future prospective studies consisting of diabetic patients are warranted to verify the exact effect of glucose levels on foetal and maternal circulation.

A maternal meal affects clinical Doppler parameters in the fetal middle cerebral artery

INTRODUCTION

Middle cerebral artery (MCA) and umbilical artery (UA) Doppler blood flow pulsatility indices (PIs) and MCA peak systolic velocity (PSV) are essential variables for clinically evaluating fetal well-being. Here we examined how a maternal meal influenced these Doppler blood flow velocity variables.

METHODS

This prospective cohort study included 89 healthy Caucasian women with normal singleton pregnancies (median age, 32 years). Measurements were performed at gestational weeks 30 and 36, representing the start and near the end of the energy-depositing period. Measured variables included the MCA-PI, UA-PI, fetal heart rate (FHR) and MCA-PSV. The cerebroplacental ratio (CPR) was calculated as the ratio of MCA-PI to UA-PI. The first examination was performed in the fasting state at 08:30 a.m. Then participants ate a standard breakfast (approximate caloric intake, 400kcal), and the examination was repeated ~105 min after the meal.

RESULTS

Without adjustment for FHR, fetal MCA-PI decreased after the meal at week 30 (‒0.115; p = 0.012) and week 36 (‒0.255; p < 0.001). All PI values were negatively correlated with FHR. After adjustment for FHR, MCA-PI still decreased after the meal at week 30 (‒0.087; p = 0.044) and week 36 (‒0.194; p < 0.001). The difference between the two gestational weeks was non-significant (p = 0.075). UA-PI values did not significantly change at week 30 (p = 0.253) or week 36 (p = 0.920). CPR revealed significant postprandial decreases of -0.17 at week 30 (p = 0.006) and -0.22 at week 36 (p = 0.001). Compared to fasting values, MCA-PSV was significantly higher after food intake: +3.9 cm/s at week 30 (p < 0.001) and +5.9 cm/s at week 36 (p < 0.001).

CONCLUSION

In gestational weeks 30 and 36, we observed a postprandial influence that was apparently specific to fetal cerebral blood flow.

Cerebral blood flow characteristics and biometry in fetuses undergoing prenatal intervention for aortic stenosis with evolving hypoplastic left heart syndrome

Children with hypoplastic left heart syndrome (HLHS) are at risk for neurodevelopmental dysfunction; prenatal factors may play a role in this predilection. Cerebral blood flow profiles are abnormal in fetuses with HLHS, raising the possibility that cerebral hemodynamics in utero may be related to neurodevelopmental abnormalities. Prenatal aortic valvuloplasty for fetal aortic stenosis with evolving HLHS is technically feasible and improves left heart hemodynamics. This study aimed to assess the effects of prenatal intervention on cerebral blood flow profiles and head circumference in fetuses with evolving HLHS. Seventy fetuses underwent prenatal aortic valvuloplasty for evolving HLHS (median 23 weeks gestation). Among 46 fetuses that had successful valvuloplasty and available data, middle cerebral artery (MCA) pulsatility (PI) and resistive (RI) indices were abnormal (Z-scores -1.7+/-1.1 and -2.2+/-1.4, p<0.001). Early post-valvuloplasty (n=33) and at late gestation follow-up (n=28), MCA PI and RI Z-scores remained low with no difference from pre- or early postintervention. Fetal head circumference was normal, as were umbilical artery PI and RI Z-scores. Cerebral blood flow characteristics are abnormal in mid-gestation fetuses with evolving HLHS, suggesting low cerebral vascular impedance. The mechanisms and significance of these abnormalities are unknown. Prenatal aortic valvuloplasty did not have a major impact on these indices. (E-mail: doff.mcelhinney@cardio.chboston.org).

Doppler sonographic characteristics of umbilical and uterine arteries during oral glucose tolerance testing in healthy pregnant women

PURPOSE

Studies have shown that maternal hyperglycemia may be associated with increased placental resistance to blood flow and possibly adverse perinatal outcomes. The aim of this study was to determine whether Doppler velocimetric dynamics change in the uterine and umbilical arteries in healthy pregnant women (without gestational diabetes) during acute hyperglycemia induced by oral glucose tolerance testing.

METHODS

Flow in the umbilical and right and left uterine arteries was assessed by spectral Doppler sonographic examination of healthy pregnant women at 24-28 weeks' menstrual age. Four Doppler studies were conducted for each woman: 1 before oral administration of 100 g of glucose and 3 more at 1, 2, and 3 hours after glucose administration. The systolic-to-diastolic ratio was calculated for the umbilical artery, and the resistance index was calculated separately for the left and right uterine arteries.

RESULTS

All results of oral glucose tolerance testing were normal, and Doppler signals were obtained in all 30 patients enrolled. No abnormal systolic-to-diastolic ratios or resistance indices were detected in any of the examinations. No significant differences in waveforms or resistance indices between the right and left uterine arteries were found during the various testing intervals.

CONCLUSIONS

Acute hyperglycemia induced in healthy pregnant women does not affect blood flow velocimetric characteristics in the umbilical or uterine arteries at any stage of oral glucose tolerance testing.