Doppler velocimetry of the uterine, umbilical and fetal middle cerebral arteries in pregnant women undergoing tocolysis with oral nifedipine

A comparison of the effects of nifedipine and indomethacin used in preterm labor tocolytic treatment on feto-maternal Doppler ultrasonography flow

OBJECTIVE

To compare the effects of nifedipine and indomethacin, used for tocolytic purposes in the treatment of preterm labor (PTL), on fetal-maternal Doppler blood flows and perinatal outcomes.

MATERIALS AND METHODS

Eighty pregnant women between weeks 24 and 32 of gestation who used nifedipine (n = 40) and indomethacin (n = 40) as tocolytic treatments due to PTL were prospectively and consecutively included in the study. Sociodemographic, obstetric, and laboratory and Doppler flow parameters were compared between the groups.

RESULTS

Statistically significant differences were observed between the groups in terms of gestational age at delivery and birth weight, Doppler flows (umbilical artery (UA) Pulsatility Index (PI), and UA Resistance Index (RI)) at 12, 24, and 48 h, middle cerebral artery RI at 12 h, and ductus venosus (DV) PI and DV-RI at 12, 24, and 48 h (p < 0.05).

CONCLUSIONS

The findings of this study showed that nifedipine and indomethacin used in the treatment of PTL had significant effects on UA-PI and UA-RI Doppler flows at 12, 24, and 24 h, MCA-RI Doppler flows at 12 h, and DV-PI and DV-RI Doppler flows at 12, 24, and 48 h. Further studies involving larger numbers of participants are now needed to support these results.

Effect of Nifedipine Used in the Treatment of the Threat of Preterm Labor on Total Uterine Artery Blood Volume Flow Rate

PURPOSE

Evaluation of the effect of maternal nifedipine treatment on total uterine artery blood volume flow rate (TVFR).

METHODS

In this prospective study, 43 women who were admitted to the Perinatology Department of the University of Health Sciences Etlik Zübeyde Hanım Gynecology Training and Research Hospital, with the diagnosis of the threat of preterm labor, and 40 healthy pregnant women, who were randomly selected as the control group, were evaluated between July 1, 2018, and September 1, 2018. A transabdominal ultrasound examination of uterine arteries was performed both before and 48 hours after administration of oral nifedipine for TVFR measurement. For the final analysis, the TVFR levels of the group diagnosed with the threat of preterm labor and the control group were compared.

RESULTS

There was no significant difference in either uterine artery pulsatility index or resistance index values as well as the diameters of the uterine arteries after nifedipine treatment (p>0.05 for all). Total uterine artery blood volume flow rate (TVFR) was 424.66±236.74 mL/min before and 543.39±309.68 mL/min after treatment with nifedipine and was statistically significantly higher (p < 0.05).

CONCLUSIONS

Our study showed a statistically significant increase in total uterine artery blood volume flow rate 48 hours after oral nifedipine treatment.

Effects of nifedipine on fetal cardiac function in preterm labor

Objectives To evaluate the effects of nifedipine treatment on fetal hemodynamics and cardiac function during preterm labor. This prospective study assessed several quantitative parameters of fetal cardiac circulation and function, and found no significant changes at 48 h after nifedipine treatment. These findings suggest that tocolytic nifedipine may be safe for fetuses. It supports clinicians to use nifedipine treatment for tocolysis without any cardiac effect on the fetus. Methods A prospective cohort study was conducted at a tertiary hospital between January 2016 and October 2017. A total of 45 pregnant women who required nifedipine for preterm labor were included in this study. Fetal Doppler ultrasound was performed and fetal systolic and diastolic function was measured prior to, and 48 h after, the first nifedipine treatment. Conventional Doppler parameters were used to evaluate fetal heart function and hemodynamic changes. Tricuspid annular plane systolic excursion, mitral annular plane systolic excursion and the sphericity index were also evaluated to assess changes in fetal cardiac morphology. Results No significant changes in fetal Doppler parameters were observed following nifedipine tocolysis. There was no significant difference in the fetal cardiac function parameters of both ventricles before vs. after nifedipine treatment. Tricuspid annular plane systolic excursion, mitral annular plane systolic excursion, and sphericity index values were unchanged following nifedipine treatment. Conclusions Oral administration of nifedipine did not to alter fetal cardiac function or morphology. Fetal cardiac parameters and various Doppler indices were unchanged following nifedipine treatment. Maternal nifedipine treatment does not appear to have any significant effect on fetal cardiac function.

Maternal and fetal parameters in pregnant woman undergoing tocolysis with nifedipine

Abstract Objectives: to evaluate the effects of nifedipine with tocolysis under maternal and fetal parameters. Methods: a cohort study with 40 pregnant women admitted at a high-risk pregnancy ward to inhibit premature labor between September/2010 to May/2012. Nifedipine was used as a 20mg sublingual attack dose and maintained 20mg every six and eight hours orally. The variables of the analysis were fetal heart rate (FHR), maternal heart rate (MHR), systolic blood pressure (SBP) and diastolic blood pressure (DBP), and amniotic fluid index (AFI). All the variables were evaluated prior to administrating nifedipine and approximately after 6 hours and every 24 hours, until hospital discharge. Results: there were no modification of the FHR (p=0.48) and the SBP (p=0.29). The MHR increased after 24 hours, but with no statistical difference (p=0.08), returning to similar levels as at admission within 48 hours. The DBP decreased at 6 (p=0.04) to 72 hours, being stable afterwards. The AFI decreased significantly at 24, 48 and 72 hours. Conclusions: the use of high doses of nifedipine with tocolysis causes a decrease of the maternal’s diastolic blood pressure and consequently decreases the amniotic fluid index, but probably without any clinical repercussions.

Acute Tocolysis - a Critical Analysis of Evidence-Based Data

Tocolysis is among the most common obstetric measures. The objective is to prolong the pregnancy by at least 48 hours to complete foetal lung maturation and for the in-utero transfer of the pregnant woman to a perinatal centre. The indication for tocolysis is regular, premature contractions (≥ 4/20 min) and a dynamic shortening of the cervical length/cervical opening between 22 + 0 to 33 + 6 weeks of pregnancy. In this connection, the cervical length measured on ultrasound and the determination of biomarkers in the cervicovaginal secretions can be important decision-making aids. Beta sympathomimetics should no longer be used due to the high rate of severe maternal adverse effects. Given controversial data, magnesium sulphate is no longer recommended for tocolysis in current guidelines. Atosiban is as effective for prolonging pregnancy as beta sympathomimetics and nifedipine, has the lowest rate of maternal adverse effects, but also the highest drug costs. Nifedipine and indomethacin are recommended in international guidelines for acute tocolysis, however there are indications of increased neonatal morbidity following indomethacin. Current problems are, above all, the lack of randomised, controlled comparative and placebo-controlled studies, the data which are controversial to some extent, and the insufficient evidence of tocolytics to significantly improve the neonatal outcome.

An effect of maternal nifedipine therapy on fetoplacental blood flow: a prospective study

PURPOSE

The aim of this study is to assess the effects of maternal nifedipine administration on placental and fetal blood flow.

METHODS

A total of 29 patients with preterm labor diagnosis admitted to the tertiary care center, Zeynep Kamil Hospital, were evaluated. Before and 24-48 h after administration of oral nifedipine, Doppler ultrasound scan was carried out to measure fetal middle cerebral artery, ductus venosus, umbilical artery, and maternal uterine artery blood flow.

RESULTS

After 24 and 48 h of therapy, there were no changes in mean PI and RI in the umbilical arteries and ductus venosus (p > 0.05). Fetal middle cerebral artery and maternal uterine artery PI and RI values showed a significant reduction 24-48 h after oral nifedipine therapy (p < 0.05).

CONCLUSIONS

Our study showed that 24 and 48 h after oral nifedipine therapy, there is a significant increase in fetal MCA and maternal uterine artery blood flow, while fetal umbilical artery and ductus venosus Doppler values do not change.

Effect of nifedipine and atosiban on perinatal brain injury: secondary analysis of the APOSTEL-III trial

OBJECTIVE

Brain injury in neonates born prematurely is associated strongly with poor neurodevelopmental outcome. The aim of this study was to evaluate whether tocolysis with nifedipine or atosiban in women with threatened preterm birth can reduce the incidence of overall brain injury in neonates born prematurely.

METHODS

This was a secondary analysis of the APOSTEL-III trial (Dutch Clinical Trial Registry, no. NTR2947), a randomized clinical trial in which women with threatened preterm labor between 25 and 34 weeks of gestation were allocated to treatment with nifedipine or atosiban. In this secondary analysis, women delivered at ≤ 32 weeks of gestational age in the two main contributing centers were included. Primary outcome was the presence of neonatal brain injury, which was defined as presence of abnormalities on ultrasound investigation and classified into mild and severe. To evaluate type and severity of brain injury, all neonatal ultrasounds performed during neonatal intensive and medium care admission were analyzed. To test the robustness of our results, a sensitivity analysis was performed assessing differences in baseline or known risk factors for brain injury.

RESULTS

A total of 117 neonates (from 102 women) were studied, of which 51 had been exposed to nifedipine and 66 to atosiban. Brain injury was observed in 22 (43.1%) neonates in the nifedipine group compared with 37 (56.1%) in the atosiban group (OR, 0.60; 95% CI, 0.29-1.24). Presence of mild brain injury was comparable between the nifedipine (33.3%) and atosiban (48.5%) groups (OR, 0.53; 95% CI, 0.25-1.13). Severe brain injury was also comparable between the groups, observed in 9.8% of neonates in the nifedipine vs 7.6% of those in the atosiban group (OR, 1.33; 95% CI, 0.36-4.85). Intraventricular hemorrhage (≥ Grade I) was the most frequently seen ultrasound abnormality, observed in 18 (35.3%) neonates in the nifedipine group vs 25 (37.9%) in the atosiban group (OR, 0.90; 95% CI, 0.42-1.91). The sensitivity analysis, with adjustment for maternal age and gestational age at randomization, showed no statistical difference between the groups for presence of brain injury (OR, 0.58; 95% CI, 0.27-1.27).

CONCLUSION

In children born before 32 weeks of gestation after the use of tocolytics, the prevalence of brain injury was high. No significant differences were found with respect to overall brain injury between neonates exposed to nifedipine and those exposed to atosiban. However, as this study was a secondary analysis of the APOSTEL III trial, it was underpowered for brain injury. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Effects of betamethasone on fetoplacental and maternal hemodynamics in preterm pregnancies

OBJECTIVE

To evaluate the possible effects of prenatal steroid administration on Doppler parameters of the umbilical artery, uterine artery, middle cerebral artery, and ductus venosus, the cerebroplacental ratio, and the amniotic fluid index in preterm fetuses.

METHODS

The present prospective observational study was performed at the Perinatology Department of Trakya University, Edirne, Turkey, between June 1, 2015, and September 1, 2016. It included patients with healthy singleton pregnancies who had received betamethasone at 24-34 weeks of pregnancy. Doppler parameters were measured before (0 hours) and 24, 48, and 72 hours after the administration of betamethasone (two intramuscular doses of 12 mg each, administered 24 hours apart).

RESULTS

There were 68 patients included. Pairwise comparisons demonstrated that, at 72 hours after betamethasone administration, the umbilical artery resistance index (P=0.038), the middle cerebral artery systolic/diastolic velocity ratio (P=0.007), and the amniotic fluid index (P=0.017) were reduced, whereas the end-diastolic velocity of the middle cerebral artery was increased (P=0.012), compared with baseline values.

CONCLUSION

Betamethasone had favorable effects on fetal cerebral circulation, with increased end-diastolic velocity in the middle cerebral artery; this could represent a positive effect on cerebral blood circulation and decreased flow resistance in the umbilical artery.

Nifedipine increases fetoplacental perfusion

AIM

Our aim is to evaluate the effect of nifedipine on fetoplacental hemodynamic parameters.

METHODS

A retrospective study was conducted at a tertiary center with 30 patients for whom nifedipine treatment was used as a tocolytic therapy for preterm labor. Initiation of this treatment was at 31.6±2.5 weeks of gestation. We combined the pulse Doppler imaging parameters with grayscale imaging via the Bernoulli theorem, which is called the "continuity equation", to get the fetoplacental perfusion (FPP). Evaluated parameters were the resistance index (RI), the pulsatility index (PI), systole/diastole ratios (S/D), the velocity-time integral of the umbilical artery (VTI), the radius of the umbilical artery, the peak systolic velocity and the mean pressure gradient in the umbilical artery. From these parameters, the FPP was acquired.

RESULTS

We found that the RI, the PI and the S/D ratio did not change after treatment with nifedipine. The mean pressure gradient, the VTI and the peak systolic velocity increased after treatment with nifedipine. Nifedipine increases FPP from 166±73.81 beat.cm3/min to 220±83.3 beat.cm3/min.

DISCUSSION

Although nifedipine had no effect on the PI, the RI or the S/D, it increased the mean pressure gradient, the VTI and FPP.

The Effect of Maternal Antihypertensive Drugs on the Cerebral, Renal and Splanchnic Tissue Oxygen Extraction of Preterm Neonates

BACKGROUND

Drugs with antihypertensive action are frequently used in obstetrics for the treatment of preeclampsia (labetalol) and tocolysis (nifedipine) or for neuroprotection (MgSO4), and may affect the hemodynamics of preterm born neonates.

OBJECTIVE

The aim of this study was to assess whether maternal antihypertensive drugs affect multisite oxygenation levels of the neonate.

METHODS

Eighty preterm neonates of ≤32 weeks of gestational age were monitored using near-infrared spectroscopy. Mean cerebral, renal and splanchnic fractional tissue oxygen extractions (cFTOE, rFTOE and sFTOE) were calculated for the first 5 postnatal days. We determined the effect of various maternal antihypertensive drugs on cFTOE and rFTOE using multilevel analysis, and on sFTOE using Kruskal-Wallis and Mann-Whitney U tests.

RESULTS

Eleven infants were exposed to labetalol ± MgSO4, 7 to nifedipine ± MgSO4, 20 to MgSO4 only, and 42 to no maternal antihypertensive drugs. The infants exposed to labetalol ± MgSO4 had a lower cFTOE on days 1 (0.14, p = 0.031), 2 (0.13, p = 0.035) and 4 (0.18, p = 0.046) than nonexposed infants on the corresponding days (0.22, 0.20 and 0.24, respectively). On day 2, cFTOE was also lower in infants exposed to nifedipine ± MgSO4 (0.11, p = 0.028) and to MgSO4 only (0.15, p = 0.047). sFTOE was higher in infants exposed to labetalol ± MgSO4 on days 1 (µ = 0.71) and 2 (µ = 0.82) than in nonexposed infants (µ = 0.26, p = 0.04 and µ = 0.55, p = 0.007, respectively). Maternal antihypertensive drugs did not affect rFTOE.

CONCLUSIONS

Low neonatal cFTOE found with maternal antihypertensive drug exposure may relate to either increased cerebral perfusion or neurologic depression induced by the medication, or preferential brain perfusion associated with preeclampsia placental insufficiency. Concomitantly high sFTOE found with labetalol exposure supports the latter, while renal autoregulation may explain rFTOE stability.

The effect of nifedipine tocolysis on Doppler indices of the uterine and umbilical arteries

PURPOSE

The aim of this study was to evaluate the effect of oral nifedipine on Doppler indices of the uterine artery (UtA) and umbilical artery (UA) before and 24 hours, 48 hours, and 1 week after tocolytic treatment.

METHODS

This was a prospective, self-controlled, cohort study of 65 pregnant women undergoing nifedipine tocolysis. Doppler assessment of the UtA and UA was performed before treatment and 24 hours, 48 hours, and 1 week after the initial 4 doses of 10 mg of oral nifedipine, administered at 20-minute intervals. The maintenance dosage was 20 mg of oral nifedipine administered every 6 hours for 48 hours, for a total dose of 80 mg/day.

RESULTS

There was a decrease in the 24-hour values of the UA pulsatility index, resistance index (RI), systolic-diastolic (S:D) ratio, right UtA pulsatility index, RI, S:D ratio, and left UtA RI and S:D ratio with nifedipine therapy in comparison with the values recorded prior to nifedipine therapy. However, these differences were not statistically significant. There were no statistically significant differences between the data recorded prior to nifedipine administration and those obtained at 48 hours and 1 week after treatment.

CONCLUSIONS

Oral nifedipine is a safe tocolytic agent with no long-term effect on fetomaternal circulation in pregnant women at risk of preterm delivery.

Comparison of measurements of the transverse diameter and perimeter of the fetal thymus obtained by magnetic resonance and ultrasound imaging

PURPOSE

To compare measurements of the fetal thymus obtained by magnetic resonance imaging (MRI) and ultrasound (US).

MATERIALS AND METHODS

Written informed consent was obtained from the patients that participated in this Institutional Review Board-approved observational study. The study population consisted of 17 pregnant women carrying fetuses between 21 and 34 weeks of gestation with suspected abnormalities. The transverse diameter and perimeter of the thymus were measured in these fetuses at the level of an axial view of the thorax that includes the pulmonary, aorta, and superior vena cava. The degree of agreement between MRI and US measurements was determined using Lin's concordance correlation coefficient and Bland-Altman analysis.

RESULTS

The mean (standard deviation, SD) gestational age at the time of the prenatal evaluation was 28.4 weeks (3.6). The thymus was measured by MRI and US in all cases. Comparison of the measurements from these two imaging modalities demonstrated a relatively good reproducibility with no evidence of systematic error.

CONCLUSION

MRI and US measurements of the fetal thymus during the second half of pregnancy are comparable. This finding suggests that MRI can become a useful adjuvant to US for assessment of the fetal thymus.

The MCA Doppler and its role in the evaluation of fetal anemia and fetal growth restriction

Doppler velocimetry of the middle cerebral artery (MCA) has played a major role in fetal medicine for the last 23 years, both in intrauterine growth-restricted (IUGR) and anemic fetuses. Its utility in the diagnosis and management of cases of fetal anemia was initially demonstrated in cases of red cell alloimmunization and later extended to other types of anemia. In addition, MCA Doppler studies are crucial in the evaluation of IUGR fetuses. This article is a review of the role of the MCA in these 2 conditions.