Evidence of brain injury in fetuses of mothers with preterm labor with intact membranes and preterm prelabor rupture of membranes

BACKGROUND

Brain injury and poor neurodevelopment have consistently been reported in infants and adults born preterm. These changes occur at least in part prenatally and are associated with intra-amniotic inflammation. The pattern of brain changes has been partially documented by magnetic resonance imaging but not with neurosonography in combination with amniotic fluid brain injury biomarkers.

OBJECTIVES

To evaluate the prenatal features of brain remodeling and injury in fetuses from patients with preterm labor with intact membranes or preterm prelabor rupture of membranes and to investigate the potential influence of intra-amniotic inflammation as a mediator of risk.

STUDY DESIGN

In this prospective cohort study, fetal brain remodeling and injury was evaluated by neurosonography and amniocentesis in singleton pregnant patients with preterm labor with intact membranes or preterm prelabor rupture of membranes between 24.0-34.0 weeks, with (n=41) and without (n=54) intra-amniotic inflammation. Controls for neurosonography were outpatient pregnant patients without preterm labor or preterm prelabor rupture of membranes matched 2:1 by gestational age at ultrasound. Amniotic fluid controls were patients with an amniocentesis performed for indications other than preterm labor or preterm prelabor rupture of membranes without brain or genetic defects whose amniotic fluid was collected in our biobank for research purposes matched by gestational age at amniocentesis. The group with intra-amniotic inflammation included those with intra-amniotic infection (microbial invasion of the amniotic cavity and intra-amniotic inflammation) and those with sterile inflammation. Microbial invasion of the amniotic cavity was defined as a positive amniotic fluid culture and/or positive 16S ribosomal RNA gene. Inflammation was defined by amniotic fluid interleukin-6 >13.4 ng/ml in preterm labor and >1.43 ng/ml in preterm prelabor rupture of membranes. Neurosonography included the evaluation of brain structure biometric parameters and cortical development. As amniotic fluid brain injury biomarkers we selected neuron-specific enolase, protein S100B and glial fibrillary acidic protein. Data was adjusted for cephalic biometrics, fetal growth centile, fetal sex, non-cephalic presentation and preterm prelabor rupture of membranes at admission.

RESULTS

Fetuses from mothers with preterm labor with intact membranes or preterm prelabor rupture of membranes had signs of brain remodeling and injury. First, they had a smaller cerebellum. Thus, in intra-amniotic inflammation, non- intra-amniotic inflammation and control groups, transcerebellar diameter (median (25th; 75th percentile)) was 32.7mm (29.8; 37.6), 35.3mm (31.2;39.6) and 35.0mm (31.3;38.3), respectively (p=0.019); vermian height was 16.9 mm (15.5 ;19.6), 17.2 mm (16.0;18.9) and 17.1mm (15.7;19.0), respectively (p=0.041). Second, they presented a lower corpus callosum area (0.72mm2 (0.59;0. 81), 0.71mm2 (0.63;0.82) and 0.78mm2 (0.71;0. 91), respectively (p=0.006). Third, they showed a delayed cortical maturation (Sylvian fissure depth / biparietal diameter ratio was 0.14 (0.12;0.16), 0.14 (0.13;0.16) and 0.16 (0.15;0.17), respectively (p<0.001), and right parieto-occipital sulci depth ratio was 0.09 (0.07;0.12), 0.11 (0.09;0.14) and 0.11 (0.09;0.14), respectively (p=0.012)). Finally, regarding amniotic fluid brain injury biomarkers, fetuses from mothers with preterm labor with intact membranes or preterm prelabor rupture of membranes, had higher concentrations of neuron-specific enolase (11804.6pg/ml (6213.4;21098.8), 8397.7 pg/ml (3682.1;17398.3) and 2393.7pg/ml (1717.1;3209.3), respectively (p<0.001)); protein S100B (2030.6 pg/ml (993;4883.5), 1070.3pg/ml (365.1-1463.2) and 74.8pg/ml (44.7;93.7), respectively (p<0.001)), and glial fibrillary acidic protein (1.01ng/ml (0.54;3.88), 0.965ng/ml (0.59;2.07) and 0.24mg/ml (0.20;0.28), respectively (p=0.002)).

CONCLUSION

Fetuses with preterm labor with intact membranes or preterm prelabor rupture of membranes had prenatal signs of brain remodeling and injury at the time of clinical presentation. These changes were more pronounced in those with intra-amniotic inflammation.

Pulmonary vascular reactivity in growth restricted fetuses using computational modelling and machine learning analysis of fetal Doppler waveforms

The aim of this study was to investigate the pulmonary vasculature in baseline conditions and after maternal hyperoxygenation in growth restricted fetuses (FGR). A prospective cohort study of singleton pregnancies including 97 FGR and 111 normally grown fetuses was carried out. Ultrasound Doppler of the pulmonary vessels was obtained at 24-37 weeks of gestation and data were acquired before and after oxygen administration. After, Machine Learning (ML) and a computational model were used on the Doppler waveforms to classify individuals and estimate pulmonary vascular resistance (PVR). Our results showed lower mean velocity time integral (VTI) in the main pulmonary and intrapulmonary arteries in baseline conditions in FGR individuals. Delta changes of the main pulmonary artery VTI and intrapulmonary artery pulsatility index before and after hyperoxygenation were significantly greater in FGR when compared with controls. Also, ML identified two clusters: A (including 66% controls and 34% FGR) with similar Doppler traces over time and B (including 33% controls and 67% FGR) with changes after hyperoxygenation. The computational model estimated the ratio of PVR before and after maternal hyperoxygenation which was closer to 1 in cluster A (cluster A 0.98 ± 0.33 vs cluster B 0.78 ± 0.28, p = 0.0156). Doppler ultrasound allows the detection of significant changes in pulmonary vasculature in most FGR at baseline, and distinct responses to hyperoxygenation. Future studies are warranted to assess its potential applicability in the clinical management of FGR.

A multivariable prediction model for intra-amniotic infection in patients with preterm labor and intact membranes including a point of care system that measures amniotic fluid MMP-8

OBJECTIVES

Among patients with preterm labor and intact membranes (PTL), those with intra-amniotic infection (IAI) present the highest risk of adverse perinatal outcomes. Current identification of IAI, based on microbiological cultures and/or polymerase chain reaction amplification of the 16S ribosomal RNA gene, delay diagnosis and, consequently, antenatal management. The aim to of the study was to assess the performance of a multivariable prediction model for diagnosing IAI in patients with PTL below 34.0 weeks using clinical, sonographic and biochemical biomarkers.

METHODS

From 2019 to 2022, we prospectively included pregnant patients admitted below 34.0 weeks with diagnosis of PTL and had undergone amniocentesis to rule in/out IAI. The main outcome was IAI, defined by a positive culture and/or 16S ribosomal RNA gene in amniotic fluid. Based on the date of admission, the sample (n=98) was divided into a derivation (2019-2020, n=49) and validation cohort (2021-2022, n=49). Logistic regression models were developed for the outcomes evaluated. As predictive variables we explored ultrasound cervical length measurement at admission, maternal C-reactive protein, gestational age, and amniotic fluid glucose and matrix metalloproteinase-8 (MMP-8) levels. The model was developed in the derivation cohort and applied to the validation cohort and diagnostic performance was evaluated. Clinical management was blinded to the model results.

RESULTS

During the study period, we included 98 patients admitted with a diagnosis of PTL. Of these, 10 % had IAI. The final model included MMP-8 and amniotic fluid glucose levels and showed an area under the receiver operating characteristic curve to predict the risk of IAI of 0.961 (95 % confidence interval: 0.860-0.995) with a sensitivity of 75 %, specificity of 93.3 %, positive likelihood ratio (LR) of 11.3 and negative LR of 0.27 in the validation cohort.

CONCLUSIONS

In patients with PTL, a multivariable prediction model including amniotic fluid MMP-8 and glucose levels might help in the clinical management of patients undergoing amniocentesis to rule in/out IAI, providing results within a few minutes.

Intra-amniotic infection and/or inflammation is associated with fetal cardiac concentric hypertrophy and diastolic dysfunction in preterm labor and preterm prelabor rupture of membranes

BACKGROUND

Preterm delivery is associated with cardiovascular remodeling and dysfunction in children and adults. However, it is unknown whether these effects are caused by the neonatal consequences of preterm birth or if these are already present in utero.

OBJECTIVE

We evaluated fetal cardiac morphology and function in fetuses of mothers admitted for preterm labor or preterm prelabor rupture of membranes and the association of these changes with the presence of intra-amniotic infection and/or inflammation.

STUDY DESIGN

In this prospective cohort study, fetal echocardiography and amniocentesis were performed at admission in singleton pregnant women with preterm labor and/or preterm prelabor rupture of membranes between 24.0 and 34.0 weeks' gestation with (intra-amniotic infection and/or inflammation group, n=41) and without intra-amniotic infection and/or inflammation (non-intra-amniotic infection and/or inflammation, n=54). Controls (n=48) were outpatient pregnant women without preterm labor or preterm prelabor rupture of membranes. Intra-amniotic infection was defined by a positive amniotic fluid culture or positive 16S ribosomal RNA gene. Intra-amniotic inflammation was defined by using the amniotic fluid interleukin-6 cutoff levels previously reported by our group being >1.43 ng/mL in preterm prelabor rupture of membranes and >13.4 ng/mL in preterm labor. Fetal cardiac morphology and function was evaluated using echocardiography, and troponin-I and N-terminal pro-brain natriuretic peptide concentrations were measured in amniotic fluid from women with preterm labor or preterm prelabor rupture of membranes and compared with 20 amniotic fluid Biobank samples obtained for reasons other than preterm labor or preterm prelabor rupture of membranes or cardiac pathology. The data were adjusted for the estimated fetal weight below the 10th percentile and for preterm prelabor rupture of membranes at admission and also for gestational age at amniocentesis when amniotic fluid biomarkers were compared.

RESULTS

From 2018 to 2021, 143 fetuses were included; 95 fetuses were from mothers admitted with a diagnosis of preterm labor or preterm prelabor rupture of membranes, and among those, 41 (28.7%) were in the intra-amniotic infection and/or inflammation group and 54 (37.8%) were in the non-intra-amniotic infection and/or inflammation group. A total of 48 (33.6%) fetuses were included in the control group. Fetuses with preterm labor and/or preterm prelabor rupture of membranes had signs of subclinical cardiac concentric hypertrophy (median left wall thickness of 0.93 [interquartile range, 0.72-1.16] in the intra-amniotic infection and/or inflammation group; 0.79 [0.66-0.92] in the non-intra-amniotic infection and/or inflammation group; and 0.69 [0.56-0.83] in controls; P<.001) and diastolic dysfunction (tricuspid A duration 0.23 seconds [0.21-0.25], 0.24 [0.22-0.25], and 0.21 [0.2-0.23]; P=.007). Systolic function was similar among groups. Higher values of amniotic fluid troponin I (1413 pg/mL [927-2334], 1190 [829-1636], and 841 [671-959]; P<.001) and N-terminal pro-brain natriuretic peptide were detected (35.0%, 17%, and 0%; P=.005) in fetuses with preterm labor or preterm prelabor rupture of membranes when compared with the control group. The highest N-terminal pro-brain natriuretic peptide concentrations were found in the intra-amniotic infection and/or inflammation group.

CONCLUSION

Fetuses with preterm labor or preterm prelabor rupture of membranes showed signs of cardiac remodeling and subclinical dysfunction, which were more pronounced in those exposed to intra-amniotic infection and/or inflammation. These findings support that the cardiovascular effects observed in children and adults born preterm have, at least in part, a prenatal origin.

Mortality and severe neurological morbidity in extremely preterm growth-restricted fetuses

OBJECTIVE

To develop a model for the prediction of adverse perinatal outcome in growth-restricted fetuses requiring delivery before 28 weeks in order to provide individualized patient counseling.

METHODS

This was a retrospective multicenter cohort study of singleton pregnancies with antenatal suspicion of fetal growth restriction requiring delivery before 28 weeks' gestation between January 2010 and January 2020 in six tertiary public hospitals in the Barcelona area, Spain. Separate predictive models for mortality only and mortality or severe neurological morbidity were created using logistic regression from variables available antenatally. For each model, predictive performance was evaluated using receiver-operating-characteristics (ROC)-curve analysis. Predictive models were validated externally in an additional cohort of growth-restricted fetuses from another public tertiary hospital with the same inclusion and exclusion criteria.

RESULTS

A total of 110 cases were included. The neonatal mortality rate was 37.3% and, among the survivors, the rate of severe neurological morbidity was 21.7%. The following factors were retained in the multivariate analysis as significant predictors of mortality: magnesium sulfate neuroprotection, gestational age at birth, estimated fetal weight, male sex and Doppler stage. This model had a significantly higher area under the ROC curve (AUC) compared with a model including only gestational age at birth (0.810 (95% CI, 0.730-0.889) vs 0.695 (95% CI, 0.594-0.795); P = 0.016). At a 20% false-positive rate, the model showed a sensitivity, negative predictive value and positive predictive value of 66%, 80% and 66%, respectively. For the prediction of the composite adverse outcome (mortality or severe neurological morbidity), the model included: gestational age at birth, male sex and Doppler stage. This model had a significantly higher AUC compared with a model including only gestational age at birth (0.810 (95% CI, 0.731-0.892) vs 0.689 (95% CI, 0.588-0.799); P = 0.017). At a 20% false-positive rate, the model showed a sensitivity, negative predictive value and positive predictive value of 55%, 63% and 74%, respectively. External validation of both models yielded similar AUCs that did not differ significantly from those obtained in the original sample.

CONCLUSIONS

Estimated fetal weight, fetal sex and Doppler stage can be combined with gestational age to improve the prediction of death or severe neurological sequelae in growth-restricted fetuses requiring delivery before 28 weeks. This approach may be useful for parental counseling and decision-making. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of adverse neonatal outcome at admission for early-onset preeclampsia with severe features

BACKGROUND

Preeclampsia remains the leading cause of maternal morbidity and mortality. Consequently, research has focused on validating tools to predict maternal outcomes regarding clinical and biochemical features from the maternal compartment. However, preeclampsia also leads to neonatal complications due to placental insufficiency and prematurity, being the early-onset type associated with the poorest outcome. Hence, it is imperative to study whether these existing tools can predict adverse neonatal outcome.

OBJECTIVE

To assess the predictive value for adverse neonatal outcome of Doppler ultrasound, angiogenic factors and multi-parametric risk-score models in women with early-onset severe preeclampsia.

STUDY DESIGN

This is a prospective cohort study of consecutive singleton pregnancies complicated by early-onset (developed before 34 week's gestation) severe preeclampsia.

RESULTS

63 women with early-onset severe preeclampsia, 18 (28.6%) presented an adverse neonatal outcome. Placental growth factor (PlGF) showed the best discrimination between neonatal outcomes among angiogenic factors. PREP-L score is a multi-parametric risk-score for the prediction of complications in early-onset preeclampsia which includes maternal characteristics and clinical and analytical data obtained at admission. Good predictive values for the prediction of neonatal complications were found with the combination of PREP-L score with advanced Doppler (AUC ROC 0.9 95% CI 0.82-0.98]) and with PlGF levels (AUC ROC 0.91 [95% CI 0.84-0.98]).

CONCLUSIONS

The combination of maternal risk scoring (PREP-L score) with angiogenic factors or fetal Doppler ultrasound at the time of diagnosis of early-onset preeclampsia with severe features performs well in predicting adverse neonatal outcome.

Death and severe morbidity in isolated periviable small-for-gestational-age fetuses

OBJECTIVE

This study aims to predict perinatal death or severe sequelae in isolated small-for-gestational-age fetuses, diagnosed at a periviable gestational age, based on ultrasound and Doppler parameters at diagnosis.

DESIGN

Observational study.

SETTING

A tertiary perinatal centre.

POPULATION

A cohort of singleton non-malformed fetuses suspected to be small for gestational age (estimated fetal weight, EFW, <10th centile) diagnosed at 22.0-25.6 weeks of gestation. The following parameters were recorded at diagnosis: severe smallness (<3rd centile); absent or reversed end-diastolic velocity in umbilical artery; abnormal middle cerebral artery Doppler; abnormal cerebroplacental ratio; abnormal uterine artery Doppler; and absent or reversed end-diastolic velocity in the ductus venosus.

METHODS

Logistic regression analysis.

MAIN OUTCOME MEASURES

Predictive performance of EFW and Doppler parameters for short-term adverse outcome of perinatal morbimortality and composite serious adverse outcomes (death, neurological impairment or severe bronchopulmonary dysplasia).

RESULTS

A total of 155 pregnancies were included. There were 13 (8.4%) intrauterine and 11 (7.7%) neonatal deaths. A short-term adverse perinatal outcome occurred in 40 (25.8%) pregnancies. There were 31 (20%) cases of serious adverse outcomes. For the prediction of serious adverse outcomes, the combination of absent or reversed end-diastolic velocity in the umbilical artery and impaired middle cerebral artery detected by Doppler evaluation achieved a detection rate of 87%, with a false-positive rate of 14% (accuracy 86%).

CONCLUSION

In periviable isolated small-for-gestational-age fetuses, a Doppler evaluation of the umbilical and fetal brain circulation can accurately predict short-term adverse perinatal complications and serious adverse outcomes.

Noninvasive prediction models of intra-amniotic infection in women with preterm labor

BACKGROUND

Among women with preterm labor, those with intra-amniotic infection present the highest risk of early delivery and the most adverse outcomes. The identification of intra-amniotic infection requires amniocentesis, perceived as too invasive by women and physicians. Noninvasive methods for identifying intra-amniotic infection and/or early delivery are crucial to focus early efforts on high-risk preterm labor women while avoiding unnecessary interventions in low-risk preterm labor women.

OBJECTIVE

This study modeled the best performing models, integrating biochemical data with clinical and ultrasound information to predict a composite outcome of intra-amniotic infection and/or spontaneous delivery within 7 days.

STUDY DESIGN

From 2015 to 2020, data from a cohort of women, who underwent amniocentesis to rule in or rule out intra-amniotic infection or inflammation, admitted with a diagnosis of preterm labor at <34 weeks of gestation at the Hospital Clinic and Hospital Sant Joan de Déu, Barcelona, Spain, were used. At admission, transvaginal ultrasound was performed, and maternal blood and vaginal samples were collected. Using high-dimensional biology, vaginal proteins (using multiplex immunoassay), amino acids (using high-performance liquid chromatography), and bacteria (using 16S ribosomal RNA gene amplicon sequencing) were explored to predict the composite outcome. We selected ultrasound, maternal blood, and vaginal predictors that could be tested with rapid diagnostic techniques and developed prediction models employing machine learning that was applied in a validation cohort.

RESULTS

A cohort of 288 women with preterm labor at <34 weeks of gestation, of which 103 (35%) had a composite outcome of intra-amniotic infection and/or spontaneous delivery within 7 days, were included in this study. The sample was divided into derivation (n=116) and validation (n=172) cohorts. Of note, 4 prediction models were proposed, including ultrasound transvaginal cervical length, maternal C-reactive protein, vaginal interleukin 6 (using an automated immunoanalyzer), vaginal pH (using a pH meter), vaginal lactic acid (using a reflectometer), and vaginal Lactobacillus genus (using quantitative polymerase chain reaction), with areas under the receiving operating characteristic curve ranging from 82.2% (95% confidence interval, ±3.1%) to 85.2% (95% confidence interval, ±3.1%), sensitivities ranging from 76.1% to 85.9%, and specificities ranging from 75.2% to 85.1%.

CONCLUSION

The study results have provided proof of principle of how noninvasive methods suitable for point-of-care systems can select high-risk cases among women with preterm labor and might substantially aid in clinical management and outcomes while improving the use of resources and patient experience.

Severe smallness as predictor of adverse perinatal outcome in suspected late small-for-gestational-age fetuses: systematic review and meta-analysis

OBJECTIVE

To investigate the performance of severe smallness in the prediction of adverse perinatal outcome among fetuses with suspected late-onset small-for-gestational age (SGA).

METHODS

A systematic search was performed to identify relevant studies in PubMed, Web of Science and Scopus. Late-onset SGA was defined as estimated fetal weight (EFW) or abdominal circumference (AC) < 10^th percentile diagnosed at or after 32 weeks' gestation, while severe SGA was defined as EFW or AC < 3^rd percentile or < 2 SD. Random-effects modeling was used to generate hierarchical summary receiver-operating-characteristics (HSROC) curves. The performance of severe SGA (as a presumptive diagnosis) in predicting adverse perinatal outcome among singleton pregnancies with suspected late-onset SGA was expressed as area under the HSROC curve (AUC), sensitivity, specificity and positive/negative likelihood ratios. The association between suspected severe SGA and adverse perinatal outcome was also assessed by random-effects modeling using the Mantel-Haenszel method and presented as odds ratio (OR). The non-exposed group was defined as non-severe SGA (EFW ≥ 3^rd centile).

RESULTS

Twelve cohort studies were included in this systematic review and meta-analysis. The studies included a total of 3639 fetuses with suspected late-onset SGA, of which 1246 had suspected severe SGA. Significant associations were found between suspected severe SGA and composite adverse perinatal outcome (OR, 1.97 (95% CI, 1.33-2.92)), neonatal intensive care unit admission (OR, 2.87 (95% CI, 1.84-4.47)) and perinatal death (OR, 4.26 (95% CI, 1.07-16.93)). However, summary ROC curves showed limited performance of suspected severe SGA in predicting perinatal outcomes, with AUCs of 60.9%, 66.9%, 53.6%, 57.2%, 54.6% and 64.9% for composite adverse perinatal outcome, neonatal intensive care unit admission, neonatal acidosis, Cesarean section for intrapartum fetal compromise, low Apgar score and perinatal death, respectively.

CONCLUSION

Although suspected severe SGA was associated with a higher risk of perinatal complications, it performed poorly as a standalone parameter in predicting adverse perinatal outcome. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Impact of the COVID-19 Pandemic on Maternal Well-Being during Pregnancy

The outbreak of a pandemic has negative psychological effects. We aimed to determine the impact of the SARS-CoV-2 pandemic during pregnancy and identify the risk factors for maternal well-being. A multicenter, prospective, population-based study was carried out that included women (n = 1320) who were pregnant during the SARS-CoV-2 pandemic in Barcelona (Spain) compared against a pre-pandemic cohort (n = 345). Maternal well-being was assessed using the validated World Health Organization Well-Being Index Questionnaire (WHO-5 Index). Pregnant women attended during the COVID-19 pandemic showed worst WHO-5 well-being scores (median (IQR) of 56 (36−72) for the pandemic cohort vs. 64 (52−76) for the pre-pandemic cohort p < 0.001), with 42.8% of women presenting a poor well-being score vs. 28% for the pre-pandemic cohort (p < 0.001). Presence of a previous psychiatric disorder (OR 7.1; 95% CI 2.6−19, p < 0.001), being in the third trimester of pregnancy (OR 1.7; 95% CI 1.5−2, p < 0.001), or requiring hospital admission for COVID-19 (OR 4.7; 95% CI 1.4−16.7, p = 0.014), significantly contributed to low maternal well-being during the COVID-19 pandemic (multivariate analysis). Being infected by SARS-CoV-2 was not associated with a lower well-being score. We conclude that, during the COVID-19 pandemic, there were higher rates of poor maternal well-being; the infection of SARS-CoV-2 itself did not worsen maternal well-being, but other factors as psychiatric disorders, being in the third trimester of pregnancy or hospital admission for COVID-19 disease did.

How to define late fetal growth restriction

A fraction of third-trimester small fetuses does not achieve their endowed growth potential mainly due to placental insufficiency, usually not evident in terms of impaired umbilical artery Doppler, but severe enough to increase the risk of perinatal adverse outcomes and long-term complications. The identification of those fetuses at higher-risk helps to optimize their follow-up and to decrease the risk of intrauterine demise. Several parameters can help in the identification of those fetuses at higher risk, defined as fetal growth restricted (FGR) fetuses. Severe smallness and the cerebroplacental ratio are the most consistent parameters; regarding uterine artery Doppler, although some evidence in favour has been published, there is currently no consensus about its use. Thirty-two weeks of gestation is the accepted cut-off to define late FGR. The differentiation with early FGR is necessary as these two entities have different clinical maternal manifestations, and different associated short-term and long-term neonatal outcomes. The use of angiogenic factors is promising but more research is needed on this field.

Doppler studies of placental function

Placental-associated diseases account for most cases of adverse perinatal outcome in developing countries. Doppler evaluation has been incorporated as a predictive parameter at early pregnancy for high-risk placental disease, in the diagnosis and management of those fetuses with impaired intrauterine growth and for the evaluation of fetal wellbeing in those high-risk pregnancies. Uterine Doppler at second trimester predicts most instances of early-onset preeclampsia and intrauterine growth restriction. However, the growing evidence of an effective early propylactic strategy, has turned Uterine Doppler an essential parameter to be included in first trimester predictive algorithms. Umbilical artery Doppler helps in the identification of small-for-gestational-age fetuses at higher risk, and is one of the essential vessels in the assessment of fetal hypoxia impairment, especially in the early cases. It helps in the decision timing for ending the pregnancy improving thus perinatal outcomes. Moreover, in high-risk pregnancies, umbilical artery Doppler has demonstrated to reduce the risk of perinatal deaths and the risk of obstetric interventions. On the other hand, middle cerebral artery Doppler reflects fetal adaptation to hypoxia, and with the cerebroplacental ratio, they improve the detection of fetuses a high risk of adverse perinatal outcome, mostly of those late small fetuses, where most instances of adverse outcome occur in fetuses with normal umbilical artery. Ductus venosous Doppler waveform is a surrogate parameter of the fetal base-acid status. Its use has demonstrated to improve perinatal outcomes, mainly reducing the risk of fetal intrauterine death. Alone or in combination with computerized CTG, it helps tailoring the best moment to end the pregnancy among early cases.

Ten-year experience of protocol-based management of small-for-gestational-age fetuses: perinatal outcome in late-pregnancy cases diagnosed after 32 weeks

OBJECTIVE

To report our 10-year experience of protocol-based management of small-for-gestational-age (SGA) fetuses, based on standardized clinical and Doppler criteria, in late-pregnancy cases.

METHODS

A retrospective cohort was constructed of consecutive singleton pregnancies referred for late-onset (> 32 weeks) SGA (defined as estimated fetal weight (EFW) < 10^th centile) that were classified as fetal growth restriction (FGR) or low-risk SGA, based on the severity of smallness (EFW < 3^rd centile) and the presence of Doppler abnormalities (uterine artery pulsatility index (UtA-PI) ≥ 95^th centile or cerebroplacental ratio (CPR) < 5^th centile). Low-risk SGA pregnancies were followed at 2-week intervals and delivered electively at 40 weeks. FGR pregnancies were followed at 1-week intervals, or more frequently if there were signs of fetal deterioration, and were delivered electively after 37 + 0 weeks' gestation. The occurrence of stillbirth and composite adverse outcome (CAO; defined as neonatal death, metabolic acidosis, need for endotracheal intubation or need for admission to the neonatal intensive care unit) was analyzed in low-risk SGA and FGR pregnancies.

RESULTS

A total of 1197 pregnancies with EFW < 10^th centile were identified and classified at diagnosis as low-risk SGA (n = 619; 51.7%) or FGR (n = 578; 48.3%). Of these, 160 were delivered before 37 weeks' gestation; for obstetric reasons in 93 (58.1%) cases, severe pre-eclampsia in 33 (20.6%), FGR with severe hypoxia in 47 (29.4%) and stillbirth in four (2.5%) (indications are non-exclusive). During follow-up, 52/574 (9.1%) low-risk SGA pregnancies were reclassified as FGR, whereas 22/463 (4.8%) FGR pregnancies were reclassified as low-risk SGA. Overall, there were no stillbirths in the low-risk SGA group and four in the FGR group, all of which occurred before 37 weeks. There were no instances of neonatal death in pregnancies delivered ≥ 37 weeks. The risk of CAO was higher in those meeting antenatal criteria for FGR at 37 weeks than in those classified as low-risk SGA (32/493 (6.5%) vs 15/544 (2.8%); odds ratio, 2.5 (95% CI, 1.3-4.6)). In FGR pregnancies, the adjusted odds ratio (95% CI) for CAO was 6.3 (1.8-21.1) in those with EFW < 3^rd centile, while it was 3.2 (1.5-6.8) and 4.2 (1.9-8.9) in those with UtA-PI ≥ 95^th centile and CPR < 5^th centile, respectively, as compared to FGR pregnancies without each of these criteria.

CONCLUSION

Protocol-based risk stratification with different management and monitoring schemes for late pregnancy with a suspected SGA baby, based on clinical and Doppler criteria, enables identification and tailored assessment of high-risk FGR, while allowing expectant management with safe perinatal outcome for low-risk SGA fetuses. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Receptor cell habituation in the A1 auditory receptor of four noctuoid moths

Moths of both sexes of Empyreuma affinis (=pugione) and Syntomeida epilais (Arctiidae, Ctenuchinae), Maenas jussiae (Arctiidae, Arctiinae) and Spodoptera frugiperda (Noctuidae, Amphipyrinae) were studied. Spike activity in the A1 cell was recorded using a stainless-steel hook electrode from the tympanic nerve in the mesothorax. Acoustic stimuli consisting of 25 and 100 ms pulses at the best frequency for the species and at intensities that evoke A1 cell saturation response were used at repetition rates of 0.5 and 5 Hz for 100 ms stimuli, and between 2 and 20 Hz for 25 ms stimuli. Stimuli at a repetition rate corresponding to a duty cycle of 5 % (25 ms at 2 Hz and 100 ms at 0.5 Hz) did not evoke monotonic changes in the responses of the A1 cell. With 25 ms pulses, rates above 5 Hz evoked an exponential decrease in the number of spikes and an increase in the latency of the responses of all the 37 specimens tested. The response duration showed no apparent change with stimulus repetition rates even at the highest duty cycle used (50 %), i.e. 25 ms at 20 Hz and 100 ms at 5 Hz. The higher the rate of stimulus repetition, the more marked were the changes in the A1 cell responses. In 16 of 17 preparations from two species, habituation had no effect on the adaptation rate in each response, while in seven of eight specimens of another species, the adaptation rate decreased with stimulus repetition. These results, and those from another mechanoreceptor cell, indicate that receptor cell adaptation (changes evoked in the response by a stimulus of constant intensity) and habituation (changes in the responses due to stimulus repetition rate) are two distinctive phenomena. The A1 cell in its habituated state showed an increase in its response to incremental increases in stimulus intensity of 10 dB. This result supports the idea that receptor cell habituation does not seem to be due to fatigue, i.e. to a temporary loss of the ability to respond to stimulation induced in a sensory receptor by continued stimulation.