Fetal ischemia monitoring with in vivo implanted electrochemical multiparametric microsensors

Under intrauterine growth restriction (IUGR), abnormal attainment of the nutrients and oxygen by the fetus restricts the normal evolution of the prenatal causing in many cases high morbidity being one of the top-ten causes of neonatal death. The current gold standards in hospitals to detect this relevant problem is the clinical observation by echography, cardiotocography and Doppler. These qualitative techniques are not conclusive and requires risky invasive fetal scalp blood testing and/or amniocentesis. We developed micro-implantable multiparametric electrochemical sensors for measuring ischemia in real time in fetal tissue and vascular. This implantable technology is designed to continuous monitoring for an early detection of ischemia to avoid potential fetal injury. Two miniaturized electrochemical sensors were developed based on oxygen and pH detection. The sensors were optimized in vitro under controlled concentration, to assess the selectivity and sensitivity required. The sensors were then validated in vivo in the ewe fetus model, by means of their insertion in the muscle leg and inside the iliac artery of the fetus. Ischemia was achieved by gradually obstructing the umbilical cord to regulate the amount of blood reaching the fetus. An important challenge in fetal monitoring is the detection of low levels of oxygen and pH changes under ischemic conditions, requiring high sensitivity sensors. Significant differences were observed in both; pH and pO2 sensors under changes from normoxia to hypoxia states in the fetus tissue and vascular with both sensors. Herein, we demonstrate the feasibility of the developed sensors for future fetal monitoring in medical applications.

The Diagnostic Ability of the Cerebroplacental Ratio for the Prediction of Adverse Perinatal Outcome and Intrapartum Fetal Compromise within One Day of Delivery

<b><i>Objectives:</i></b> The objectives of this study were to evaluate the diagnostic abilities of the cerebroplacental ratio (CPR) for the prediction of adverse perinatal outcome (APO) and cesarean section for intrapartum fetal compromise (CS-IFC) within 1 day of delivery. <b><i>Design:</i></b> Retrospective observational case-control study. <b><i>Methods:</i></b> This was a study of 254 high-risk fetuses attending the day hospital unit of a tertiary referral hospital that underwent an ultrasound examination at 32–41 weeks and gave birth within 1 day of examination. APO was defined as a composite of abnormal intrapartum fetal heart rate or intrapartum fetal scalp pH &#x3c;7.20 requiring urgent cesarean section, neonatal umbilical cord pH &#x3c;7.10, 5-min Apgar score &#x3c;7, and postpartum admission to neonatal or pediatric intensive care units. CS-IFC was defined in case of abnormal intrapartum fetal heart rate or intrapartum fetal scalp pH &#x3c;7.20 requiring urgent cesarean section. The diagnostic ability of CPR for the prediction of APO and CS-IFC was calculated alone and in combination with estimated fetal weight and gestational clinical parameters, including the type of labor onset, using ROC curves and logistic regression analysis. <b><i>Results:</i></b> CPR in multiples of the median (MoM) was a moderate predictor of APO (area under the curve [AUC] = 0.77, <i>p</i> &#x3c; 0.0001) and CS-IFC (AUC = 0.82, <i>p</i> &#x3c; 0.0001). The predictive abilities of the multivariable model for APO (AUC = 0.81, <i>p</i> &#x3c; 0.0001) and CS-IFC (AUC = 0.82, <i>p</i> &#x3c; 0.0001) did not differ from those of CPR alone . <b><i>Limitations:</i></b> The small number of cases and the scarcity of information concerning labor induction. <b><i>Conclusion:</i></b> In high-risk pregnancies, CPR MoM is a moderate predictor of APO and CS-IFC when performed within 24 h of delivery.

Prognostic Value of Cerebroplacental Ratio in Appropriate-for-Gestational-Age Fetuses Before Induction of Labor in Late-Term Pregnancies

Purpose To evaluate the relationship between cerebroplacental ratio (CPR) and the need for operative delivery due to intrapartum fetal compromise (IFC) and adverse perinatal outcome (APO) in appropriate-for-gestational-age (AGA) late-term pregnancies undergoing induction of labor. The predictive performance of CPR was also assessed. Materials and Methods Retrospective study including singleton AGA pregnancies that underwent elective induction of labor between 41 + 0 and 41 + 6 weeks and were delivered before 42 + 0 weeks. IFC was defined as persistent pathological CTG or pathological CTG and fetal scalp pH < 7.20. Operative delivery included instrumental vaginal delivery (IVD) and cesarean section (CS). APO was defined as a composite of umbilical artery pH < 7.20, Apgar score < 7 at 5 minutes, and admission to the neonatal intensive care unit for > 24 hours. Results The study included 314 women with 32 (10 %) IVDs and 49 (16 %) CSs due to IFC and 85 (27 %) APO cases. Fetuses with CPR < 10th percentile showed a significantly higher rate of operative delivery for IFC (40 % (21/52) vs. 23 % (60/262); p = 0.008) yet not a significantly higher rate of APO (31 % (16/52) vs. 26 % (69/262); p = 0.511). The predictive values of CPR for operative delivery due to IFC and APO showed sensitivities of 26 % and 19 %, specificities of 87 % and 84 %, positive LRs of 2.0 and 1.2, and negative LRs of 0.85 and 0.96, respectively. Conclusion Low CPR in AGA late-term pregnancies undergoing elective induction of labor was associated with a higher risk of operative delivery for IFC without increasing the APO rate. However, the predictive value of CPR was poor.

Preterm Labour

Preterm delivery is defined as delivery before 37 weeks completed gestation. It represents a major cause of neonatal morbidity and mortality and accounts for 5–10% of all deliveries. Cervical length assessment between 16–24 weeks and positive fetal fibronectin beyond 21 weeks gestation are proved to useful tools in prediction of preterm labour. Treating asymptomatic bacteruia and bacterial vaginosis in high-risk women reduces the incidence of preterm labour. Cervical cerclage is recommended to reduce the incidence of preterm birth in women with 2nd trimester losses and those with cervical length of 25 mm or less on transvaginal ultrasound between 16–24 weks gestation. Atosiban and nifidipine are currently the agents of choice in tocolysis. Antenal steriods in womens with threating preterm labour reduces the perinatal morbidties. Magnisum sulphate role is established for neuroprotection especially in extreme gestations between 24–30 weeks. Vaginal delivery is mode of choice for delivery with consideration to avoid fetal blood sampling, fetal scalp electrodes and ventouse prior to 34 weeks gestations. Caesarean section is considered for obstetric reasons that guide labour management at term.

Neonatal brain abscess development following fetal scalp electrode placement: a rare complication

A fetal scalp electrode (FSE) is a frequently used investigation during labor. However, it is an invasive procedure which can lead to complications. Our patient developed a very large brain abscess after initial superficial infection of the skin site due to an FSE. The patient was admitted to the hospital after an asymmetric growth of the skull was noticed with no further signs of clinical illness. MRI showed a very large brain abscess which was aspirated and treated with antibiotics for 10 weeks. A 2-year follow-up showed only a slight developmental delay in gross motor skills. Only once before a similar case has been described at which the patient developed a brain abscess after superficial infection of the scalp following an FSE. In both cases, the brain abscess was noticed due to an asymmetric growth of the skull without any further signs of clinical illness. A brain abscess has a high mortality and morbidity rate, and early diagnosis is vital for the optimal outcome. We therefore recommend to organize an out-patient clinical follow-up for every infant with a superficial infection of the skin site after placement of an FSE.

Proposed cut-off for fetal scalp blood lactate in intrapartum fetal surveillance based on neonatal outcomes: a prospective observational study

Objective Determination of lactate in fetal scalp blood (FBS) during labor has been studied since the 1970s. The internationally accepted cut-off of >4.8mmol/L indicating fetal acidaemia is exclusive for the point-of-care device (POC) LactateProTM, which is no longer in production. The aim of this study was to present a new cut-off for scalp lactate based on neonatal outcomes with the use of StatstripLactate®/StatstripXpress® Lactate system, the only POC lactate meter designed for hospital use. Design Observational Study Setting January 2016 to March 2020 labouring women with an indication for FBS were prospectively included from seven Swedish and one Australian delivery unit. Population Inclusion criteria: singleton pregnancy, vertex presentation, ≥35+0 gestational weeks. Method Based on the optimal correlation between FBS lactate and cord pH/lactate, only cases with ≤25 minutes from FBS to delivery were included in the final calculations. Main outcome measures Metabolic acidosis in cord blood was defined as pH <7.05 plus BDecf >10 mmol/L and/or lactate >10 mmol/L. Results 3334 women were enrolled of which 799 were delivered within 25 minutes. The areas under the ROC curves (AUC) and corresponding optimal lactate cut-off values were as follows; metabolic acidosis AUC 0.87(95% CI:0.77-0.97), cut-off 5.7mmol/L; pH <7.0 AUC 0.83(95% CI:0.68-0.97), cut-off 4.6mmol/L; pH <7.05 plus BD ≥12mmol/L AUC 0.97(95% CI:0.92-1), cut-off 5.8mmol/L; Apgar score <7 at 5 minutes AUC 0.74(95% CI:0.63-0.86), cut-off 5.2mmol/L; and pH <7.10 plus composite neonatal outcome AUC 0.76(95% CI:0.67-0.85), cut-off 4.8mmol/L. Conclusions Suggested intervention threshold for fetal acidemia is scalp lactate of 5.2mmol/L using the StatstripLactate®/StatstripXpress®.