Reply to Rubin, J.M.; Kripfgans, O.D. Comment on "Barbieri et al. Umbilical Vein Blood Flow in Uncomplicated Pregnancies: Systematic Review of Available Reference Charts and Comparison with a New Cohort. J. Clin. Med. 2023, 12, 3132".

We thank the authors for the interest in our paper [...].

A longitudinal study on the effect of obesity upon circulating renin-angiotensin system in normal pregnancy.

BACKGROUND AND AIMS: Obesity is the most common health issue in women of reproductive age, which profoundly affects maternal-fetal health. Despite progress in understanding key inflammatory and metabolic changes, the pathogenesis of the cardiovascular phenotype of obese pregnant women remains to be fully understood. This study aimed at: (i) evaluating the changes of the renin-angiotensin system (RAS) throughout pregnancy in obese vs normal weight (control) women, and (ii) evaluating the presence of any associations between maternal hemodynamic status and RAS changes. METHODS AND RESULTS: Thirty-eight normal weight and nineteen obese pregnant women were included. Clinical assessment, blood samples and maternal hemodynamic evaluation were performed at 12, 20, 30, and 36 weeks, while ultrasound assessment was scheduled at 20, 30, and 36 weeks of gestation. Measurements of sFlt-1, PlGF, Angiotensinogen, Renin, AngII, Ang1-7, ACE and ACE2 were performed by ELISA. Our data show that normotensive obese women had lower placental blood supply, as assessed by UV-Q and UV-Q/EFW, as compared to controls, and significantly higher levels of AngII and AngII/Ang1-7 ratio, which were inversely related to placental blood supply. CONCLUSIONS: Our study shows for the first time that normotensive obese women exhibited a significant progressive increase of AngII and AngII/Ang1-7 throughout pregnancy, which were inversely related to placental blood supply as assessed by UV-Q and UV-Q/EFW. Our data shed light on the early changes in pregnant obese women and suggest that RAS dysregulation is a prerequisite rather than a consequence of hypertensive disorders of pregnancy and other maternal neonatal complications.

Umbilical Vein Blood Flow in Uncomplicated Pregnancies: Systematic Review of Available Reference Charts and Comparison with a New Cohort.

The objectives of the study were (1) to perform a systematic review of the available umbilical vein blood flow volume (UV-Q) reference ranges in uncomplicated pregnancies; and (2) to compare the findings of the systematic review with UV-Q values obtained from a local cohort. Available literature in the English language on this topic was identified following the PRISMA guidelines. Selected original articles were further grouped based on the UV sampling sites and the formulae used to compute UV-Q. The 50th percentiles, the means, or the best-fitting curves were derived from the formulae or the reported tables presented by authors. A prospective observational study of uncomplicated singleton pregnancies from 20+0 to 40+6 weeks of gestation was conducted to compare UV-Q with the results of this systematic review. Fifteen sets of data (fourteen sets belonging to manuscripts identified by the research strategy and one obtained from our cohort) were compared. Overall, there was a substantial heterogeneity among the reported UV-Q central values, although when using the same sampling methodology and formulae, the values overlap. Our data suggest that when adhering to the same methodology, the UV-Q assessment is accurate and reproducible, thus encouraging further investigation on the possible clinical applications of this measurement in clinical practice.

Umbilical vein blood flow: State-of-the-art.

Placental blood supply to the fetus can be measured by evaluating the umbilical vein blood flow. Despite its potential application in healthcare, the umbilical vein blood flow volume is still used only in research setting. One of the reasons is a concern regarding its reproducibility, partly due to technology issues. Nowadays, technology improvements make this evaluation accurate and reproducible. The aim of this review is to refresh basic elements of the physiology of umbilical vein blood flow and its analysis. Its evaluation in normal and abnormal fetal growth is also discussed.

Late-term fetuses with reduced umbilical vein blood flow volume: An under-recognized population at increased risk of growth restriction.

OBJECTIVES: To investigate the umbilical vein and uterine arteries blood flow volume (UV-Q, UtA-Q) in late-term pregnancies. STUDY DESIGN: This was a prospective observational cohort study of singleton pregnancies ≥40 + 0 weeks in which UV-Q and UtA-Q, both absolute and normalized for estimated fetal weight (EFW) values, were evaluated in relation to AC drop of ≥20 percentiles from 20 weeks to term, Doppler signs of fetal cerebral blood flow redistribution and composite adverse perinatal outcome. The presence of neonatal hypoglycaemia and the need of formula milk supplementation were also examined. RESULTS: The study population comprised 200 women. Fetuses with AC drop (n = 34) had a significantly lower UV-Q and UV-Q/EFW than fetuses without AC drop (n = 166): median UV-Q 184 ml/min (IQR 143-225) vs 233 ml/min (IQR 181-277), p = 0.0006; median UV-Q/EFW 55 ml/min/kg (IQR 42-66) vs 63 ml/min/kg (IQR 48-74), p = 0.03. Fetuses with cerebral blood flow redistribution (n = 48) had a significantly lower UV-Q and UV-Q/EFW than those without (n = 134): median UV-Q 210 ml/min (IQR 155-263) vs 236 ml/min (IQR 184-278), p = 0.04; median UV-Q/EFV 58 ml/min/kg (IQR 45-70) vs 65 ml/min/kg (IQR 50-76), p = 0.04. There was a significant moderate correlation between middle cerebral artery pulsatility index (MCA-PI) and UV-Q and UV-Q/EFW (Spearman Rho -0.20 and -0.20; p = 0.008 and p = 0.006). CONCLUSIONS: The umbilical vein blood flow volume might have a potential role to identify fetuses with stunted growth in late-term pregnancies.

Relationship Between Deceleration Morphology and Phase Rectified Signal Averaging-Based Parameters During Labor.

During labor, uterine contractions trigger the response of the autonomic nervous system (ANS) of the fetus, producing sawtooth-like decelerations in the fetal heart rate (FHR) series. Under chronic hypoxia, ANS is known to regulate FHR differently with respect to healthy fetuses. In this study, we hypothesized that such different ANS regulation might also lead to a change in the FHR deceleration morphology. The hypothesis was tested in an animal model comprising nine normoxic and five chronically hypoxic fetuses that underwent a protocol of umbilical cord occlusions (UCOs). Deceleration morphologies in the fetal inter-beat time interval (FRR) series were modeled using a trapezoid with four parameters, i.e., baseline b, deceleration depth a, UCO response time τ u and recovery time τ r . Comparing normoxic and hypoxic sheep, we found a clear difference for τ u (24.8±9.4 vs. 39.8±9.7 s; p < 0.05), a (268.1±109.5 vs. 373.0±46.0 ms; p < 0.1) and Δτ = τ u - τ r (13.2±6.9 vs. 23.9±7.5 s; p < 0.05). Therefore, the animal model supported the hypothesis that hypoxic fetuses have a longer response time τ u and larger asymmetry Δτ as a response to UCOs. Assessing these morphological parameters during labor is challenging due to non-stationarity, phase desynchronization and noise. For this reason, in the second part of the study, we quantified whether acceleration capacity (AC), deceleration capacity (DC), and deceleration reserve (DR), computed through Phase-Rectified Signal Averaging (PRSA, known to be robust to noise), were correlated with the morphological parameters. DC, AC and DR were correlated with τ u , τ r and Δτ for a wide range of the PRSA parameter T (Pearson's correlation ρ > 0.8, p < 0.05). In conclusion, deceleration morphologies have been found to differ between normoxic and hypoxic sheep fetuses during UCOs. The same difference can be assessed through PRSA based parameters, further motivating future investigations on the translational potential of this methodology on human data.

Evidence of bacterial DNA presence in chorionic villi and amniotic fluid in the first and second trimester of pregnancy.

The sterile-womb dogma in uncomplicated pregnancy has been lively debated. Data regarding the in utero microbiome environment are based mainly on studies performed at the time of delivery. Aim: To determine whether human placenta and amniotic fluid are populated by a bacterial microbiota in the first and second trimesters of pregnancy. Materials & methods: We analyzed by next-generation sequencing method 24 and 29 samples from chorionic villus sampling (CVS) and amniocentesis (AC), respectively. The V3 region of the 16S rRNA gene was sequenced. Results: 37.5% of CVS and 14% of AC samples showed the presence of bacterial DNA. Conclusion: Our study suggests that bacterial DNA can be identified in the placenta and amniotic fluid during early prenatal life.

Prenatal diagnosis of isolated clubfoot: Diagnostic accuracy and long-term postnatal outcomes.

OBJECTIVE: To evaluate concordance between prenatal and postnatal diagnosis of congenital talipes equinovarus (cTEV), rates of surgery and postnatal outcomes in relation to the prenatal classification of severity. STUDY DESIGN: This is a retrospective observational cohort study on fetuses with a prenatal diagnosis of cTEV between 2004 and 2018. All cases of isolated cTEV in singleton pregnancies were included. Postnatally, the Ponseti method was applied. Children were followed-up postnatally for at least two years, with a specific focus on neurodevelopmental outcome. RESULTS: The cohort included 81 fetuses with a prenatal diagnosis of cTEV confirmed postnatally in 86.4% of cases. Concordance between prenatal and postnatal assessment was good for both laterality and degree of severity (k = 0.61 and 0.66, respectively). The average Pirani score, number of casts and rates of Achilles tendon tenotomy were higher for III degree cTEV (p < 0.001). Within this group only, the rate of relapse was 11% and the rates of major surgery was 6%. The postnatal outcome was normal in 68.6% newborns, while 14% of cases had a diagnosis of minor additional findings and 17% had an impairment of neurological development. None of the outcome was statistically correlated to the prenatal assessment of laterality or degree. CONCLUSIONS: The accuracy of prenatal ultrasound for isolated cTEV is 86% with a false positive diagnosis of 14%. The grade of cTEV assigned prenatally correlates to postnatal severity and longer orthopedic rehabilitation in terms of number of casts and need of surgery. The assessment of the correlation between cTEV and neurological impairment requires further prospective studies on larger cohorts.

Neurodevelopment of infant with late fetal growth restriction.

Late fetal growth restriction has increasingly gain interest. Differently from early fetal growth restriction, the severity of this condition and the impact on perinatal mortality and morbidity is less severe. Nevertheless, there is some evidence to suggest that fetuses exposed to growth restriction late in pregnancy are at increased risk of neurological dysfunction and behavioral impairment. The aim of our review was to discuss the available evidence on the neurodevelopmental outcome in fetuses exposed to growth restriction late in pregnancy. Cerebral blood flow redistribution, a Doppler hallmark of late fetal growth restriction, has been associated with this increased risk, although there are still some controversies. Currently, most of the available studies are heterogeneous and do not distinguish between early and late fetal growth restriction when evaluating the long-term outcome, thus, making the correlation between late fetal growth restriction and neurological dysfunction difficult to interpret. The available evidence suggests that fetuses exposed to late growth restriction are at increased risk of neurological dysfunction and behavioral impairment. The presence of the cerebral blood flow redistribution seems to be associated with adverse neurodevelopmental outcome, however, from the present literature the causality cannot be ascertained.

Prenatal findings of cataract and arthrogryposis: recurrence of cerebro-oculo-facio-skeletal syndrome and review of differential diagnosis.

BACKGROUND: Cerebro-oculo-facio-skeletal syndrome (COFS) is a severe and progressive neurologic condition characterized by prenatal onset of arthrogryposis, cataract, microcephaly and growth failure. The aim of this study was to present a case of recurrence of the COFS syndrome and to propose a differential diagnosis flow-chart in case of prenatal findings of arthrogryposis and cataract. CASE PRESENTATION: We report a case of recurrence of COFS3 syndrome within the same family, with similar diagnostic features. In the first case the COFS syndrome remained undiagnosed, while in the second case, due to prenatal findings of arthrogryposis and cataract, genetic investigation focusing on responsible genes of COFS (ERCC5, ERCC6 and FKTN genes) was carried out. The fetus was found to be compound heterozygous for two different ERCC5 mutations, confirming the clinical suspect of COFS syndrome. A review of the literature on possible causative genes of prenatal cataract and arthrogryposis was performed and we present a flow-chart to guide differential diagnosis and possible genetic testing in case of these findings. CONCLUSION: COFS syndrome is a rare autosomic recessive condition. However, it can be suspected and diagnosed prenatally. The flow-chart illustrates a pathway to guide differential diagnosis according to the prenatal findings. Main syndromes, key testing and specific genes are included. Targeted molecular testing should be offered to the couple in order to reach a diagnosis and assess the recurrence risk for future pregnancies.