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

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.

Emerging role of toll-like receptors signaling and its regulators in preterm birth: a narrative review

INTRODUCTION

Despite intensive research, preterm birth (PTB) rates have not decreased significantly in recent years due to a lack of understanding of the underlying causes and insufficient treatment options for PTB. We are committed to finding promising biomarkers for the treatment of PTB.

METHODS

An extensive search of the literature was conducted with MEDLINE/PubMed, and in total, 151 studies were included and summarized in the present review.

RESULTS

Substantial evidence supports that the infection and/or inflammatory cascade associated with infection is an early event in PTB. Toll-like receptor (TLR) is a prominent pattern recognition receptor (PRR) found on both immune and non-immune cells, including fetal membrane cells. The activation of TLR downstream molecules, followed by TLR binding to its ligand, is critical for infection and inflammation, leading to the involvement of the TLR signaling pathway in PTB. TLR ligands are derived from microbial components and molecules released by damaged and dead cells. Particularly, TLR4 is an essential TLR because of its ability to recognize lipopolysaccharide (LPS). In this comprehensive overview, we discuss the role of TLR signaling in PTB, focus on numerous host-derived genetic and epigenetic regulators of the TLR signaling pathway, and cover ongoing research and prospective therapeutic options for treating PTB by inhibiting TLR signaling.

CONCLUSION

This is a critical topic because TLR-related molecules and mechanisms may enable obstetricians to better understand the physiological changes in PTB and develop new treatment and prevention strategies.

Mechanistic insights into the development of severe fetal growth restriction

Fetal growth restriction (FGR), which most commonly results from suboptimal placental function, substantially increases risks for adverse perinatal and long-term outcomes. The only "treatment" that exists is delivery, which averts stillbirth but does not improve outcomes in survivors. Furthermore, the potential long-term consequences of FGR to the fetus, including cardiometabolic disorders, predispose these individuals to developing FGR in their future pregnancies. This creates a multi-generational cascade of adverse effects stemming from a single dysfunctional placenta, and understanding the mechanisms underlying placental-mediated FGR is critically important if we are to improve outcomes and overall health. The mechanisms behind FGR remain unknown. However, placental insufficiency derived from maldevelopment of the placental vascular systems is the most common etiology. To highlight important mechanistic interactions within the placenta, we focus on placental vascular development in the setting of FGR. We delve into fetoplacental angiogenesis, a robust and ongoing process in normal pregnancies that is impaired in severe FGR. We review cellular models of FGR, with special attention to fetoplacental angiogenesis, and we highlight novel integrin-extracellular matrix interactions that regulate placental angiogenesis in severe FGR. In total, this review focuses on key developmental processes, with specific focus on the human placenta, an underexplored area of research.

Effects of nifedipine on endothelial function, assessed by flow-mediated vasodilatation in pregnant patients

OBJECTIVES

To evaluate the endothelial function, through flow-mediated vasodilation parameters from brachial artery test in women receiving nifedipine for acute tocolysis with threatened preterm delivery.

METHODS

In a prospective study in a university-affiliated hospital, each participant served as herself control. We evaluated various parameters of endothelial function in 22 patients between 27 and 33 weeks of gestation with a diagnosis of threatened preterm delivery (TPTD) before and after 48 h of nifedipine treatment. Each patient received 80 mg nifedipine per day. The assessment tool was Brachial artery reactivity test (BART). Primary outcome was flow mediated vasodilation (FMD).

RESULTS

The average participant's age was 27 ± 4.5 years, median gestational age of 28.5 weeks, BMI, kg/m² (mean ± SD) 28.4 ± 3.3. Systolic blood pressure (mmHg) and diastolic blood pressure (mmHg) decreased from 108 ± 6 to 104 ± 5, p < .001 and from 66 ± 4 to 63 ± 4, p < .001, respectively. FMD (%) significantly decrease from 10.8 ± 6.1 to 7.2 ± 4.7, p = .03 prior to and after nifedipine treatment. The basal brachial artery diameter (mm) at rest was (3.19 ± 0.38 versus 3.39 ± 0.49, p = .28) before versus after nifedipine. The largest brachial artery diameter (mm) was (3.54 ± 0.35 versus 3.58 ± 0.44, p = .76) before versus after nifedipine.

CONCLUSIONS

Our results suggest unfavorable changes in FMD probably as a result of nifedipine used for acute tocolysis. Future prospective studies should try to evaluate the safety of acute and maintenance tocolytic therapy with nifedipine on endothelial function in pregnant women.

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.