Antenatal Surveillance of Fetal Growth Restriction

Overexpression of the aryl hydrocarbon receptor nuclear translocator partially rescues fetoplacental angiogenesis in severe fetal growth restriction

Pregnancies complicated by severe fetal growth restriction with abnormal umbilical artery Doppler velocimetry (FGRadv) are at substantial risk for adverse perinatal and long-term outcomes. Impaired angiogenesis of the placental vasculature in these pregnancies results in a sparse, poorly branched vascular tree, which structurally contributes to the abnormally elevated fetoplacental vascular resistance that is clinically manifested by absent or reversed umbilical artery Doppler indices. Previous studies have shown that aryl hydrocarbon receptor nuclear translocator (ARNT) is a key mediator of proper placental angiogenesis, and within placental endothelial cells (ECs) from human FGRadv pregnancies, low expression of ARNT leads to decreased vascular endothelial growth factor A (VEGFA) expression and deficient tube formation. Thus, the aim of the present study was to determine the effect of VEGFA administration or ARNT overexpression on angiogenic potential of FGRadv ECs. ECs were isolated and cultured from FGRadv or gestational age-matched control placentas and subjected to either vehicle vs VEGFA treatment or transduction with adenoviral-CMV (ad-CMV) vs adenoviral-ARNT (ad-ARNT) constructs. They were then assessed via wound scratch and tube formation assays. We found that VEGFA administration nominally improved FGRadv EC migration (P<0.01) and tube formation (P<0.05). ARNT overexpression led to significantly enhanced ARNT expression in FGRadv ECs (P<0.01), to a level similar to control ECs. Despite this, FGRadv EC migration (P<0.05) and tube formation (P<0.05) were still only partially rescued. This suggests that although ARNT does play a role in fetoplacental EC migration, other factors in addition to ARNT are likely also important in placental angiogenesis.

Maternal-Fetal Monitoring of Opioid-Exposed Pregnancies: Analysis of a Pilot Community-Based Protocol and Review of the Literature

OBJECTIVES

To describe/analyse a novel, community-based prenatal monitoring protocol for opioid-exposed pregnancies developed by our centre in 2014 to optimize prenatal care for this population. A literature review of published monitoring protocols for this population is also presented.

METHODS

Retrospective comparison of pre-protocol (n = 215) and post-protocol (n = 251) cohorts. Medline and Embase were searched between 2000-2016 using MeSH terms: [fetal monitoring OR prenatal care] AND [opioid-related disorders OR substance-related disorders] in Medline and [fetal monitoring OR prenatal care] AND [opiate addiction OR substance abuse] in Embase, producing 518 results. Thirteen studies included protocols for monitoring opioid-exposed pregnancies. No comprehensive monitoring protocols with high-quality supporting evidence were found.

RESULTS

We evaluated 466 opioid-exposed pregnancies, 215 before and 251 after introduction of the protocol. Since implementation, there was a significant increase in the number of opioid-exposed patients who have underwent urine drug screening (72.6% to 89.2%, P < 0.0001); a significant reduction in the number of urine drug screenings positive for illicit opioids (50.2% to 29.1%, P < 0.0001); and a significant increase in the number of patients who discontinued illicit opioid use by the time of delivery (24.7% to 39.4%, P < 0.01). There was no difference in the CS rate (27.4% vs. 26.3%, P > 0.05). There were no observed differences in the rate of preterm birth, birth weight <2500 g, or Apgar score <7 (P > 0.05).

CONCLUSIONS

Care of women with increased opioid use during pregnancy is an important but under-studied health issue. A novel protocol for focused antenatal care provision for women with opioid-exposed pregnancies improves standard of care and maternal/fetal outcomes.

Umbilical Artery Half-Peak Systolic Velocity Deceleration Time in Fetal Growth Restriction

Objective: To study the umbilical artery (UA) half-peak systolic velocity deceleration time (hPSV-DT) in pregnancies complicated by fetal growth restriction (FGR). Methods: The study included 266 singleton, high-risk pregnancies with an estimated fetal weight <10th percentile, which were examined between 24 and 40 weeks' gestation and delivered within a week from the last ultrasound evaluation. UA hPSV-DT was measured with Doppler ultrasound in the same wave used to measure the pulsatility index. UA hPSV-DT values were correlated with perinatal outcome. Results: UA hPSV-DT <5th percentile was found in 87 and 98% of fetuses with moderate and severe FGR, respectively. 94% of fetuses with a UA hPSV-DT <90 ms had poor perinatal outcome including perinatal death or prolonged admission to the neonatal intensive care unit. None of the fetuses had a UA hPSV-DT <70 ms. Perinatal death occurred in 39 fetuses; UA hPSV-DT was abnormal in all of them, with 95% of these fetuses having values of ≤120 ms. In the group of fetuses with absent/reverse end-diastolic velocity in the UA, the perinatal mortality rate was 51% for those with a UA hPSV-DT ≤90 ms and only 23% for those having a UA hPSV-DT >90 ms (p < 0.01). Conclusions: UA hPSV-DT seems to be a useful technique in the evaluation of pregnancies at risk for FGR and perinatal death. Additionally, hPSV-DT was shown to be a good predictor of perinatal death, with values of <90 ms corresponding to imminent risk of intrauterine demise and values of <70 ms being likely to be incompatible with intrauterine life.

Velamentous cord insertion as a risk factor for obstetric outcome: a retrospective case-control study

PURPOSE

Velamentous umbilical cord insertion (VCI) is associated with adverse pregnancy outcomes. Literature lacks data on Doppler. We aimed to evaluate obstetric outcomes and results of uterine and umbilical artery Doppler flowmetry associated with VCI.

MATERIALS AND METHODS

In a retrospective case-control study, 108 singleton pregnancies with VCI were age- and body mass index-matched to 108 singleton pregnancies without VCI. The main outcome parameters were obstetric outcome, pregnancy-related complications, uterine artery flowmetry at the second-trimester screening, and umbilical artery flowmetry before delivery. Statistical analysis was accomplished using Pearson's Chi-square test or Fisher's exact test, and the Mann-Whitney U test, where appropriate.

RESULTS

Pregnancies with VCI revealed a significantly higher PI in the umbilical artery during the last measurement before delivery (1.00 ± 0.25 vs. 0.90 ± 0.10; p = 0.001). Gestational age at this measurement did not differ between the groups. Fetal malformations and intrauterine fetal death were more common in pregnancies with VCI (12.7 vs. 0 %; p < 0.001, and 6.5 vs. 0 %; p = 0.014, respectively). Patients with VCI delivered significantly earlier (36.2 ± 4.5 vs. 38.4 ± 2.6; p < 0.001).

CONCLUSION

Higher rates of (early) preterm delivery were found in pregnancies with VCI. Fetuses with VCI also suffered from malformations and IUFD more frequently. The last pulsatility index value in the umbilical artery, before delivery, was significantly higher in pregnancies with VCI, which is of uncertain clinical value.

Antenatal tests of fetal wellbeing

In current obstetric practice, there is frequently a need to assess fetal wellbeing. This is particularly so in those fetuses at risk, including the small-for-gestational-age fetus or the fetus of a mother who presents with reduced fetal movements or who has an obstetric complication such as pre-eclampsia. It is important that the clinician is able to assess fetal wellbeing in such cases, especially in preterm gestations, when inappropriate delivery could have serious adverse consequences. In this paper, we review the current evidence for the use and the limitations of widely used methods of antenatal monitoring including the use of cardiotocography, biophysical profile, and ultrasound-derived parameters including umbilical artery, middle cerebral artery, and ductus venosus Doppler flow.

Impaired fetoplacental angiogenesis in growth-restricted fetuses with abnormal umbilical artery doppler velocimetry is mediated by aryl hydrocarbon receptor nuclear translocator (ARNT)

CONTEXT

Fetal growth restriction with abnormal umbilical artery Doppler velocimetry (FGRadv), reflective of elevated fetoplacental vascular resistance, is associated with increased risks of fetal morbidity and mortality even in comparison to those of growth-restricted fetuses with normal placental blood flow. One major cause of this abnormally elevated fetoplacental vascular resistance is the aberrantly formed, thin, elongated villous vessels that are seen in FGRadv placentas.

OBJECTIVE

The purpose of this study was to determine the role of fetoplacental endothelial cells (ECs) in angiogenesis in normal pregnancies and in those complicated by FGRadv.

DESIGN AND PARTICIPANTS

Human placental specimens were obtained from FGRadv and gestational age-matched, appropriately grown control pregnancies for EC isolation/culture and for immunohistochemical studies. Additional mechanistic studies were performed on ECs isolated from subjects with term, uncomplicated pregnancies.

MAIN OUTCOME MEASURES

We evaluated tube formation and differential angiogenic gene expression in FGRadv and control ECs, and we used ECs from uncomplicated pregnancies to further elucidate the molecular mechanisms by which angiogenesis is impaired in FGRadv pregnancies.

RESULTS

Tube formation assays showed that FGRadv ECs demonstrate fewer branch points and total length compared with those from gestational age-matched controls, and this defect was not rescued by exposure to hypoxia. FGRadv ECs also demonstrated lower aryl hydrocarbon receptor nuclear translocator (ARNT) expression. ARNT knockdown resulted in suppression of key angiogenic genes including vascular endothelial growth factor A expression and led to deficient tube formation.

CONCLUSIONS

ARNT expression in the placental vasculature mediates key angiogenic expression and fetoplacental EC angiogenesis, and low ARNT expression in FGRadv ECs appears to be a key factor in deficient angiogenesis. This, in turn, results in malformed thin villous vessels that structurally contribute to the abnormally elevated fetoplacental vascular resistance that is associated with high morbidity and mortality in fetal growth restriction.

Irisin in idiopathic foetal growth restriction

PURPOSE

The aim of the present study was to compare maternal serum and cord blood irisin levels in females whose pregnancies were or were not complicated by idiopathic foetal growth restriction.

METHODS

A total of 30 subjects participated. The study group consisted of 15 female patients who were referred to our perinatology clinic for delivery because of foetal growth restriction developing in the third trimester. Fifteen females with uncomplicated singleton pregnancies constituted the control group. Irisin levels were assessed in maternal serum, as well as in serum from the umbilical vein and artery.

RESULTS

The demographic features of the two groups were similar (p > 0.05). Gestational age at delivery and birth weight were higher in females with uncomplicated pregnancies (p = 0.001). Umbilical artery irisin levels were significantly lower in pregnancies complicated by foetal growth restriction compared to controls (p = 0.003). Umbilical artery irisin levels were positively correlated with foetal weight (p = 0.01) and foetal abdominal circumference (measured by ultrasonography) (p = 0.01). Maternal and umbilical vein irisin levels did not differ between the two groups (p > 0.05).

CONCLUSIONS

The data suggest that umbilical artery irisin levels were lower in pregnancies complicated by foetal growth restriction. Such lower irisin levels may contribute to the pathogenesis of this common condition, and metabolic syndrome may be a long-term consequence of idiopathic FGR.

Factors that increase reactivity during fetal nonstress testing

PURPOSE OF REVIEW

The most common method of antepartum fetal surveillance is the nonstress test (NST). Although it has satisfactory false-negative rates, dubious nonreactive results may challenge the physician. Any method or factor increasing the reactive NST results or shortening the time to attain a reactive test may be considerably useful.

RECENT FINDINGS

Most of the studies have found no effect of maternal glucose administration on fetal heart rate and fetal activity, specificity of NST, time to reactivity and percentage of reactive NST results when compared with the control group. Maternal intake of 70% cocoa or caffeine had stimulating action on the fetal reactivity, and this effect on the fetal heart rate was more marked with high concentrations of cocoa (80%). Studies on maternal positioning during NST had equivocal results. Fetal manipulation has no impact on the NST reactivity. Vibroacoustic and halogen light stimulation may be associated with a reduction in time to reactivity.

SUMMARY

These methods may increase the reactivity during a NST and may facilitate the antenatal fetal surveillance.