Search Results (37)

Accurate fetal R-peak detection from low-SNR fetal electrocardiogram (FECG) signals remains a critical challenge as current NI-FECG methods struggle to extract high SNR FECG signals and conventional algorithms fail when signal quality deteriorates. We proposed a U-Net-based method that enables robust R-peak detection directly from low-SNR FECG signals (0–12 dB), bypassing the need for high-SNR inputs that are clinically difficult to acquire. The method was evaluated on both real (A&D FECG) and synthetic (FECGSYN) databases, comparing against ten state-of-the-art detectors. The proposed method significantly reduces false predictions compared to commonly used detection algorithms, achieving a PPV of 99.81%, an SEN of 100.00%, and an F1-score of 99.91% on the A&D FECG database and a PPV of 99.96%, an SEN of 99.93%, and an F1-score of 99.94% on the FECGSYN database. Further investigation of robustness in low-SNR conditions (0 dB, 5 dB, and 10 dB) achieved 87.38% F1-score at 0 dB SNR on real signals, surpassing the best-performing algorithm implemented in Neurokit by 13.58%. In addition, the algorithm showed ≤2.65% performance variation across tolerance windows (50 reduced to 20 ms), further underscoring its detection accuracy. Overall, this work reduces the reliance on high-SNR FECG signals by reliably extracting R-peaks from suboptimal signals, providing implications for the reliability of fetal heart rate variability analysis in real-world noisy environments. Full article

Fetal heart rate variability (FHRV) is a critical indicator of fetal well-being and autonomic nervous system development during labor. Traditional monitoring methods often provide limited insights, potentially leading to delayed interventions and suboptimal outcomes. This study proposes an advanced predictive analytics approach by integrating approximate entropy analysis with a hidden Markov model (HMM) within a digital twin framework to enhance real-time fetal monitoring. We utilized a dataset of 469 fetal electrocardiogram (ECG) recordings, each exceeding one hour in duration, to ensure sufficient temporal information for reliable modeling. The FHRV data were preprocessed and partitioned into parasympathetic and sympathetic components based on downward and non-downward beat detection. Approximate entropy was calculated to quantify the complexity of FHRV patterns, revealing significant correlations with umbilical cord blood gas parameters, particularly pH levels. The HMM was developed with four hidden states representing discrete pH levels and eight observed states derived from FHRV data. By employing the Baum–Welch and Viterbi algorithms for training and decoding, respectively, the model effectively captured temporal dependencies and provided early predictions of the fetal acid–base status. Experimental results demonstrated that the model achieved 85% training and 79% testing accuracy on the balanced dataset distribution, improving from 78% and 71% on the imbalanced dataset. The integration of this predictive model into a digital twin framework offers significant benefits for timely clinical interventions, potentially improving prenatal outcomes. Full article

(1) Background: Pregnancy induces significant physiological adaptations with substantial impacts on the cardiovascular system. Hypertensive disorders of pregnancy (HDPs) are connected to significant risks of maternal and fetal complications, contributing significantly to morbidity and mortality across the globe. This study focuses on evaluating autonomic dysfunction by analyzing heart rate variability (HRV) and assessing cardiac performance through global longitudinal strain (GLS) using speckle tracking echocardiography, as well as examining diastolic function in pregnant women with HDP compared to healthy pregnant controls. (2) Methods: A case–control study was conducted involving pregnant women diagnosed with gestational hypertension (GH), preeclampsia (PE), or severe preeclampsia (SPE) as the case group, and healthy pregnant women as the control group. HRV was measured to evaluate autonomic function, GLS was assessed using speckle tracking echocardiography, and diastolic function was evaluated through standard echocardiographic parameters. Data were analyzed to compare cardiac performance and autonomic regulation between the HDP and control group, as well as among the different HDP subgroups. (3) Results: The HDP group exhibited significantly reduced HRV parameters compared to healthy controls, indicating notable autonomic dysfunction. Speckle tracking echocardiography revealed lower GLS among women with HDP, particularly in those with SPE, compared to the control group. Diastolic dysfunction was also present in the HDP group. (4) Conclusions: HRV and GLS are valuable non-invasive tools for detecting autonomic dysfunction and cardiac performance impairments in pregnant women with hypertensive disorders. These findings suggest that autonomic and cardiac dysfunctions are prevalent in HDP. Full article

Background: Fetal Alcohol Spectrum Disorder (FASD) is a consequence of prenatal alcohol exposure (PAE) associated with a range of effects, including dysmorphic features, prenatal and/or postnatal growth problems, and neurodevelopmental difficulties. Despite advances in treatment methods, there are still gaps in knowledge that highlight the need for further research. The study investigates the effect of PAE on the autonomic system, including sex differences that may aid in early FASD diagnosis, which is essential for effective interventions. Methods: During gestational days 5 to 20, five pregnant female Wistar rats were orally administered either glucose or ethanol. After 22 days, 26 offspring were born and kept with their mothers for 21 days before being isolated. Electrocardiographic recordings were taken on the 29th and 64th day. Heart rate variability (HRV) parameters were collected, including heart rate (HR), standard deviation (SD), standard deviation of normal-to-normal intervals (SDNN), and the root mean square of successive differences between normal heartbeats (RMSSD). Additionally, a biochemical analysis of basic serum parameters was performed on day 68 of the study. Results: The study found that PAE had a significant impact on HRV. While electrolyte homeostasis remained mostly unaffected, sex differences were observed across various parameters in both control and PAE groups, highlighting the sex-specific effects of PAE. Specifically, the PAE group had lower mean heart rates, particularly among females, and higher SDNN and RMSSD values. Additionally, there was a shift towards parasympathetic activity and a reduction in heart rate entropy in the PAE group. Biochemical changes induced by PAE were also observed, including elevated levels of alanine transaminase (ALT) and aspartate aminotransferase (AST), especially in males, increased creatinine concentration in females, and alterations in lipid metabolism. Conclusions: PAE negatively affects the development of the autonomic nervous system, resulting in decreased heart rate and altered sympathetic activity. PAE also induces cardiovascular abnormalities with sex-specific effects, highlighting a relationship between PAE consequences and sex. Elevated liver enzymes in the PAE group may indicate direct toxic effects, while increased creatinine levels, particularly in females, may suggest an influence on nephrogenesis and vascular function. The reduced potassium content may be linked to hypothalamus–pituitary–adrenal axis overactivity. Full article

The modality of endometrial preparation for the transfer of frozen-thawed embryos may influence maternal and fetal adaptation to pregnancy and could thus impact the results of the first trimester combined screening test. We conducted a retrospective cross-sectional study on singleton pregnancies achieved by embryo transfer of a single frozen-thawed blastocyst, comparing two different endometrial preparation protocols: natural cycle (n = 174) and hormone replacement therapy (HRT) (n = 122). The primary outcome was the risk of preeclampsia at the first trimester combined screening test. Secondary endpoints included variable reflecting fetal cardiac function (nuchal translucency and fetal heart rate), maternal adaptation (median arterial blood pressure—MAP and uterine arteries pulsatility index—UtA-PI), and placentation (pregnancy associated plasma protein A and placental growth factor). The risk of early preeclampsia was comparable in the two groups (38% vs. a 28%, p = 0.12). However, women in the natural cycle group showed lower fetal heart rate (159 [155–164] vs. 164 [158–168], p = 0.002) and higher UtA-PI (0.96 [0.74–1.18] vs. 0.72 [0.58–0.90], p < 0.001). The frequency of a screening test at high risk for aneuploidies was similar. The modality of transfer of frozen-thawed embryos is associated with changes in the variables reflecting maternal and fetal cardiovascular function. Full article

The maternal cardiovascular-circulatory system undergoes profound changes almost from the conception of a pregnancy until the postpartum period to support the maternal adaptions required for pregnancy and lactation. Maintenance of cardiovascular homeostasis requires changes in the cardiovascular autonomic responses. Here, we present a longitudinal study of the maternal cardiovascular autonomic responses to pregnancy and maternal position. Over a normal gestation, in the left lateral position there are significant changes in both time and frequency domain parameters reflecting heart rate variability. We show that cardiovascular autonomic responses to physiological stressors (standing and supine positions in late pregnancy) became significantly different with advancing gestation. In the third trimester, 60% of the subjects had an unstable heart rate response on standing, and these subjects had a significantly reduced sample entropy evident in their heart rate variability data. By 6 weeks, postpartum function returned to near the non-pregnant state, but there were consistent differences in high-frequency power when compared to nulligravid cases. Finally, we review complementary evidence, in particular from magnetic resonance imaging, that provides insights into the maternal and fetal impacts of positioning in pregnancy. This demonstrates a clear relationship between supine position and maternal hemodynamic parameters, which relates to compression of the inferior vena cava (p = 0.05). Together, these studies demonstrate new understanding of the physiology of physiological stressors related to position. Full article

Heart rate variability (HRV) has emerged as an essential non-invasive tool for understanding cardiac autonomic function over the last few decades. This can be attributed to the direct connection between the heart’s rhythm and the activity of the sympathetic and parasympathetic nervous systems. The cost-effectiveness and ease with which one may obtain HRV data also make it an exciting and potential clinical tool for evaluating and identifying various health impairments. This article comprehensively describes a range of signal decomposition techniques and time-series modeling methods recently used in HRV analyses apart from the conventional HRV generation and feature extraction methods. Various weight-based feature selection approaches and dimensionality reduction techniques are summarized to assess the relevance of each HRV feature vector. The popular machine learning-based HRV feature classification techniques are also described. Some notable clinical applications of HRV analyses, like the detection of diabetes, sleep apnea, myocardial infarction, cardiac arrhythmia, hypertension, renal failure, psychiatric disorders, ANS Activity of Patients Undergoing Weaning from Mechanical Ventilation, and monitoring of fetal distress and neonatal critical care, are discussed. The latest research on the effect of external stimuli (like consuming alcohol) on autonomic nervous system (ANS) activity using HRV analyses is also summarized. The HRV analysis approaches summarized in our article can help future researchers to dive deep into their potential diagnostic applications. Full article

A code is generally defined as a system of signals or symbols for communication. Experimental evidence is synthesized for the presence and utility of such communication in heart rate variability (HRV) with particular attention to fetal HRV: HRV contains signatures of information flow between the organs and of response to physiological or pathophysiological stimuli as signatures of states (or syndromes). HRV exhibits features of time structure, phase space structure, specificity with respect to (organ) target and pathophysiological syndromes, and universality with respect to species independence. Together, these features form a spatiotemporal structure, a phase space, that can be conceived of as a manifold of a yet-to-be-fully understood dynamic complexity. The objective of this article is to synthesize physiological evidence supporting the existence of HRV code: hereby, the process-specific subsets of HRV measures indirectly map the phase space traversal reflecting the specific information contained in the code required for the body to regulate the physiological responses to those processes. The following physiological examples of HRV code are reviewed, which are reflected in specific changes to HRV properties across the signal–analytical domains and across physiological states and conditions: the fetal systemic inflammatory response, organ-specific inflammatory responses (brain and gut), chronic hypoxia and intrinsic (heart) HRV (iHRV), allostatic load (physiological stress due to surgery), and vagotomy (bilateral cervical denervation). Future studies are proposed to test these observations in more depth, and the author refers the interested reader to the referenced publications for a detailed study of the HRV measures involved. While being exemplified mostly in the studies of fetal HRV, the presented framework promises more specific fetal, postnatal, and adult HRV biomarkers of health and disease, which can be obtained non-invasively and continuously. Full article

Our objective is to develop a model for the prediction of minimum fetal blood pressure (FBP) during fetal heart rate (FHR) decelerations. Experimental data from umbilical occlusions in near-term fetal sheep (2698 occlusions from 57 near-term lambs) were used to train a convolutional neural network. This model was then used to estimate FBP for decelerations extracted from the final 90 min of 53,445 human FHR signals collected using cardiotocography. Minimum sheep FBP was predicted with a mean absolute error of $6.7$ mmHg (25th, 50th, 75th percentiles of $2.3$, $5.2$, $9.7$ mmHg), mean absolute percentage errors of $17.3$% ($5.5$%, $12.5$%, $23.9$%) and a coefficient of determination $R^2=0.36$. While the model was unable to clearly predict severe compromise at birth in humans, there is positive evidence that such a model could predict human FBP with further development. The neural network is capable of predicting FBP for many of the sheep decelerations accurately but performed far from satisfactory at identifying FHR segments that correspond to the highest or lowest minimum FBP. These results indicate that with further work and a larger, more variable training dataset, the model could achieve higher accuracy. Full article

Background: IntraUterine Growth Restriction (IUGR) is a global public health concern and has major implications for neonatal health. The early diagnosis of this condition is crucial for obtaining positive outcomes for the newborn. In recent years Artificial intelligence (AI) and machine learning (ML) techniques are being used to identify risk factors and provide early prediction of IUGR. We performed a systematic review (SR) and meta-analysis (MA) aimed to evaluate the use and performance of AI/ML models in detecting fetuses at risk of IUGR. Methods: We conducted a systematic review according to the PRISMA checklist. We searched for studies in all the principal medical databases (MEDLINE, EMBASE, CINAHL, Scopus, Web of Science, and Cochrane). To assess the quality of the studies we used the JBI and CASP tools. We performed a meta-analysis of the diagnostic test accuracy, along with the calculation of the pooled principal measures. Results: We included 20 studies reporting the use of AI/ML models for the prediction of IUGR. Out of these, 10 studies were used for the quantitative meta-analysis. The most common input variable to predict IUGR was the fetal heart rate variability (n = 8, 40%), followed by the biochemical or biological markers (n = 5, 25%), DNA profiling data (n = 2, 10%), Doppler indices (n = 3, 15%), MRI data (n = 1, 5%), and physiological, clinical, or socioeconomic data (n = 1, 5%). Overall, we found that AI/ML techniques could be effective in predicting and identifying fetuses at risk for IUGR during pregnancy with the following pooled overall diagnostic performance: sensitivity = 0.84 (95% CI 0.80–0.88), specificity = 0.87 (95% CI 0.83–0.90), positive predictive value = 0.78 (95% CI 0.68–0.86), negative predictive value = 0.91 (95% CI 0.86–0.94) and diagnostic odds ratio = 30.97 (95% CI 19.34–49.59). In detail, the RF-SVM (Random Forest–Support Vector Machine) model (with 97% accuracy) showed the best results in predicting IUGR from FHR parameters derived from CTG. Conclusions: our findings showed that AI/ML could be part of a more accurate and cost-effective screening method for IUGR and be of help in optimizing pregnancy outcomes. However, before the introduction into clinical daily practice, an appropriate algorithmic improvement and refinement is needed, and the importance of quality assessment and uniform diagnostic criteria should be further emphasized. Full article

Objective: Evidence regarding the clinical significance of a single sporadic variable deceleration (SSD) in reactive non-stress test (NST) is scarce, and optimal management has yet to be established. We aim to evaluate whether SSD during a reactive NST at term is associated with a higher risk for fetal heart rate decelerations during labor and the need for intervention. Methods: This was a retrospective, case-control study of singleton term pregnancies at one university-affiliated medical center in 2018. The study group consisted of all pregnancies with an SSD in an otherwise reactive NST. For each case, two consecutive pregnancies without SSD were matched in a 1:2 ratio. The primary outcome was the rate of cesarean delivery (CD) due to non-reassuring fetal heart rate monitoring (NRFHRM). Results: 84 women with an SSD were compared to 168 controls. SSD during antenatal fetal surveillance did not increase the rate of CD overall or for NRFHRM (17.9% vs. 13.7% and 10.7% vs. 7.7%, respectively, p > 0.05). Rates of assisted deliveries and maternal and neonatal complications were similar between the groups. Conclusions: SSD during a reactive NST in term pregnancies is not associated with an increased risk for adverse perinatal outcomes. SSD should not necessarily require induction of labor, and expectant management is a reasonable alternative. Full article

A 34-year-old nulliparous gravid female presented with acute bilateral pyelonephritis at 29 + 5 weeks gestation. The patient was relatively well until two weeks ago when a slight increase in amniotic fluid was noted. Further investigation revealed myoglobinuria and significantly elevated levels of creatine phosphokinase. The patient was subsequently diagnosed with rhabdomyolysis. Twelve hours after admission, the patient noted reduced fetal movements. A non-stress test revealed fetal bradycardia and non-reassuring variability in fetal heart rate. An emergency cesarean section was performed, and a “floppy” female child was delivered. Genetic testing revealed congenital myotonic dystrophy, and the mother was also diagnosed with myotonic dystrophy. Rhabdomyolysis has a very low incidence in pregnancy. Herein, we report a rare case of myotonic dystrophy with rhabdomyolysis in a gravid female with no history of myotonic dystrophy. Acute pyelonephritis is a causative agent of rhabdomyolysis that results in preterm birth. Full article

Anti-Müllerian hormone (AMH) and antral follicular count (AFC) decrease in women with ovarian endometrioma (OMA) and in vitro fertilization (IVF). In addition, these parameters drop even further when women with OMA undergo surgery. In this study, the primary aim was to compare the reproductive variables in IVF-treated women with and without endometriosis. The secondary aim was to explore if the reproductive variables were modified by endometrioma surgery. In this retrospective study, 244 women undergoing IVF were enrolled at the Hospital Universitario La Paz (Madrid, Spain). Women were categorized as OMA not surgically treated (OMA; n = 124), OMA with surgery (OMA + S; n = 55), and women with infertility issues not related to OMA (control; n = 65). Demographic and clinical variables, including age, body mass index (BMI), and reproductive (AMH, AFC, number of extracted oocytes, and transferred embryos) and obstetrical data (biochemical pregnancy and fetal heart rate at 6 weeks) were collected. Adjusted logistic regression models were built to evaluate reproductive and pregnancy outcomes. The models showed that women with OMA (with and without surgery) had significantly decreased levels of AMH and AFC and numbers of cycles and C + D embryos. Women with OMA + S had similar rates of pregnancy to women in the control group. However, women with OMA had lower biochemical pregnancy than controls (aOR = 0.08 [0.01; 0.50]; p-value = 0.025). OMA surgery seems to improve pregnancy outcomes, at least until 6 weeks of gestation. However, it is important to counsel the patients about surgery expectations due to the fact that endometrioma itself reduces the quality of oocytes. Full article

The objective was to determine the prevalence of oesophageal atresia (OA) and describe the characteristics of OA cases diagnosed before the first year of life, born between 2007 and 2019, and residents in the Valencian Region (VR), Spain. Live births (LB), stillbirths (SB), and termination of pregnancy for fetal anomaly (TOPFA) diagnosed with OA were selected from the Congenital Anomalies population-based Registry of VR (RPAC-CV). The prevalence of OA per 10,000 births with 95% confidence interval was calculated, and socio-demographic and clinical variables were analyzed. A total of 146 OA cases were identified. The overall prevalence was 2.4/10,000 births, and prevalence by type of pregnancy ending was 2.3 in LB and 0.03 in both SB and TOPFA. A mortality rate of 0.03/1000 LB was observed. A relationship was found between case mortality and birth weight (p-value < 0.05). OA was primarily diagnosed at birth (58.2%) and 71.2% of the cases were associated with another congenital anomaly, mainly congenital heart defects. Significant variations in the prevalence of OA in the VR were detected throughout the study period. In conclusion, a lower prevalence in SB and TOPFA was identified compared to EUROCAT data. As several studies have identified, an association between OA cases and birth weight was found. Full article

While the effect of antenatally administered corticosteroids on fetal heart rate (HR) and heart rate variability (HRV) is well established, little information is available on how these drugs affect maternal physiology. In this secondary analysis of a prospective, observational cohort study, we quantify how corticosteroids affect maternal HR and HRV, which serve as a proxy measure for autonomic regulation. Abdominal ECG measurements were recorded before and in the five days following the administration of betamethasone—a corticosteroid commonly used for fetal maturation—in 46 women with singleton pregnancies. Maternal HR and HRV were determined from these recordings and compared between these days. HRV was assessed with time- and frequency-domain features, as well as non-linear and complexity features. In the 24 h after betamethasone administration, maternal HR was significantly increased (p < 0.01) by approximately 10 beats per minute, while HRV features linked to parasympathetic activity and HR complexity were significantly decreased (p < 0.01 and p < 0.001, respectively). Within four days after the initial administration of betamethasone, HR decreases and HRV features increase again, indicating a diminishing effect of betamethasone a few days after administration. We conclude that betamethasone administration results in changes in maternal HR and HRV, despite the heterogeneity of the studied population. Therefore, its recent administration should be considered when evaluating these cardiovascular metrics. Full article