Umbilical Artery pH Research Articles

Neuronal exosome proteins: novel biomarkers for predicting neonatal response to therapeutic hypothermia

ObjectiveCentral nervous system (CNS) derived exosomes can be purified from peripheral blood and have been used widely in adult neurological disease. Application to neonatal neurological disease deserves investigation in the...

Effects of colloid preload on the incidence of hypotension in spinal anesthesia for cesarean section: a systematic review and meta-analysis.

Background:Hypotension is a common complication caused by spinal anesthesia (SA), which may have adverse impacts on the condition of the parturient and fetus. Liquid infusion was found to be relatively effective for reducing the incidence of hypotension. However, the question of whether colloid preload can optimize hemodynamic variables in the cesarean section remains controversial. This study aims to determine the effects of colloid preload on the incidence of hypotension induced by SA in elective cesarean section.Methods:Related keywords were searched on PubMed, EMBASE, and Cochrane Library from inception dates to May 2020. Studies included were evaluated for eligibility and quality. The primary outcome was the intra-operative incidence of hypotension and severe hypotension. The secondary outcomes included the lowest intra-operative systolic blood pressure, the maximal intra-operative heart rate, the intra-operative needs of ephedrine and phenylephrine, the incidence of maternal nausea and/or vomiting, and neonatal outcomes (umbilical artery pH and Apgar scores). Apart from the above, RevMan 5.3 was used for the data analysis.Results:Altogether nine randomized controlled trials were included in the meta-analysis. There were no significant differences in the incidence of intra-operative hypotension, severe hypotension, or neonatal outcomes between the colloid preload group and control group, except for the umbilical artery pH.Conclusion:This meta-analysis suggests that colloid preload does not significantly reduce the incidence of hypotension associated with SA in elective cesarean section.

Obstetric Outcomes in Singleton Pregnancies with Abnormal Placental Cord Insertions.

There is wide variation in the management of pregnancies complicated by abnormal placental cord insertion (PCI), which includes velamentous cord insertion (VCI) and marginal cord insertion (MCI). We tested the hypothesis that abnormal PCI is associated with small for gestational age (SGA) infants. This is a retrospective cohort study of all pregnant patients undergoing anatomic ultrasound at a single institution from 2010 to 2017. Patients with abnormal PCI were matched in a 1:2 ratio by race, parity, gestational age at the time of ultrasound, and obesity to patients with normal PCIs. The primary outcome was SGA at delivery. Secondary outcomes were cesarean delivery, preterm delivery, cesarean delivery for nonreassuring fetal status, 5-minute Apgar score < 7, umbilical artery pH < 7.1, and neonatal intensive care unit admission. These outcomes were compared using univariate and bivariate analyses. Abnormal PCI was associated with an increased risk of SGA (relative risk [RR]: 2.43; 95% confidence interval [CI]: 1.26-4.69), increased risk of preterm delivery <37 weeks (RR: 3.60; 95% CI: 1.74-7.46), and <34 weeks (RR: 3.50; 95% CI: 1.05-11.63) compared with patients with normal PCI. There was no difference in rates of cesarean delivery, Apgar score of <7 at 5 minutes, acidemia, or neonatal intensive care unit admission between normal and abnormal PCI groups. In a stratified analysis, the association between abnormal PCI and SGA did not differ by the type of abnormal PCI (p for interaction = 0.46). Abnormal PCI is associated with an increased risk of SGA and preterm delivery. These results suggest that serial fetal growth assessments in this population may be warranted. · Abnormal PCI is associated with SGA infants and preterm birth.. · If an abnormal PCI is identified, the provider should consider serial growth ultrasounds.. · There is no difference in obstetric outcomes between VCI and MCI..

Associated factors with umbilical arterial pH after cesarean delivery under spinal anesthesia: a retrospective cohort study

BackgroundMaximum decrease of blood pressure and number of minutes of hypotension were independently associated with umbilical arterial pH. However, the impact of hypotension considering the duration of it on umbilical arterial pH is unknown. MethodsPregnant women aged ≥ 20 years who delivered a baby at full-term via a cesarean delivery under a single-shot spinal anesthesia between January 2017 and March 2019 were included. The main outcome was to predict umbilical arterial pH, based on the value of the time integral of hypotension. Patient demographics, patient comorbidities, and intraoperative data, including the total dose of ephedrine and phenylephrine by fetal delivery and cumulative duration of maternal hypotension, were evaluated. Maternal hypotension was reflected as a decrease in systolic arterial pressure and mean arterial pressure to < 80% of baseline values. The systolic arterial pressure and mean arterial pressure were independently included in a multiple regression analysis along with all other explanatory factors to predict the umbilical arterial pH. ResultsOf the 416 eligible patients, 381 were enrolled. When including the systolic arterial pressure or mean arterial pressure in the model, emergency cases, the total dose of ephedrine, hypertensive disorders of pregnancy, and systolic arterial pressure or mean arterial pressure values were found to be significant predictive factors of umbilical arterial pH. ConclusionOur results suggest that an elevated time integral of maternal hypotension may have a negative impact on umbilical arterial pH. Therefore, to minimize the risk of fetal acidosis, maternal hypotension should be prevented with the consideration of vasopressors selection.

Decision-to-delivery interval and neonatal outcomes for category-1 caesarean sections during the COVID-19 pandemic.

SummaryGeneral anaesthesia is known to achieve the shortest decision‐to‐delivery interval for category‐1 caesarean section. We investigated whether the COVID‐19 pandemic affected the decision‐to delivery interval and influenced neonatal outcomes in patients who underwent category‐1 caesarean section. Records of 562 patients who underwent emergency caesarean section between 1 April 2019 and 1 July 2019 in seven UK hospitals (pre‐COVID‐19 group) were compared with 577 emergency caesarean sections performed during the same period during the COVID‐19 pandemic (1 April 2020–1 July 2020) (post‐COVID‐19 group). Primary outcome measures were: decision‐to‐delivery interval; number of caesarean sections achieving decision‐to‐delivery interval < 30 min; and a composite of adverse neonatal outcomes (Apgar 5‐min score < 7, umbilical arterial pH < 7.10, neonatal intensive care unit admission and stillbirth). The use of general anaesthesia decreased significantly between the pre‐ and post‐COVID‐19 groups (risk ratio 0.48 (95%CI 0.37–0.62); p < 0.0001). Compared with the pre‐COVID‐19 group, the post‐COVID‐19 group had an increase in median (IQR [range]) decision‐to‐delivery interval (26 (18–32 [4–124]) min vs. 27 (20–33 [3–102]) min; p = 0.043) and a decrease in the number of caesarean sections meeting the decision‐to‐delivery interval target of < 30 min (374/562 (66.5%) vs. 349/577 (60.5%); p = 0.02). The incidence of adverse neonatal outcomes was similar in the pre‐ and post‐COVID‐19 groups (140/568 (24.6%) vs. 140/583 (24.0%), respectively; p = 0.85). The small increase in decision‐to‐delivery interval observed during the COVID‐19 pandemic did not adversely affect neonatal outcomes.

Oxytocin Administration in Low-Risk Women, a Retrospective Analysis of Birth and Neonatal Outcomes.

Background: In recent years, higher than the recommended rate of oxytocin use has been observed among low-risk women. This study examines the relationship between oxytocin administration and birth outcomes in women and neonates. Methods: A retrospective analysis of birth and neonatal outcomes for women who received oxytocin versus those who did not. The sample included 322 women with a low-risk pregnancy. Results: Oxytocin administration was associated with cesarean section (aOR 4.81, 95% CI: 1.80–12.81), instrumental birth (aOR 3.34, 95% CI: 1.45–7.67), episiotomy (aOR 3.79, 95% CI: 2.20–6.52) and length of the second stage (aOR 00:18, 95% CI: 00:04–00:31). In neonatal outcomes, oxytocin in labor was associated with umbilical artery pH ≤ 7.20 (OR 3.29, 95% CI: 1.33–8.14). Admission to neonatal intensive care unit (OR 0.56, 95% CI: 0.22–1.42), neonatal resuscitation (OR 1.04, 95% CI: 0.22–1.42), and Apgar score <7 (OR 0.48, 95% CI: 0.17–1.33) were not associated with oxytocin administration during labor. Conclusions: Oxytocin administration during labor for low-risk women may lead to worse birth outcomes with an increased risk of instrumental birth and cesarean, episiotomy and the use of epidural analgesia for pain relief. Neonatal results may be also worse with an increased proportion of neonates displaying an umbilical arterial pH ≤ 7.20.

Evaluation of Pregnancy Outcomes Among Women With Decreased Fetal Movements

Stillbirth is a devastating pregnancy outcome with far-reaching economic and psychosocial consequences, but despite significant investment, a screening tool for identifying those fetuses at risk for stillbirth remains elusive. Maternal reporting of decreased fetal movements (DFM) has been found to be associated with stillbirth and other adverse perinatal outcomes. To examine pregnancy outcomes of women presenting with DFM in the third trimester at a tertiary Australian center with a clear clinical management algorithm. This cohort study used data on all births meeting the inclusion criteria from 2009 through 2019 at Mater Mothers' Hospital in Brisbane, Australia. This is a tertiary center and Australia's largest maternity hospital. All singleton births without a known congenital anomaly after 28 weeks' gestation were included. Among 203 071 potential participants identified from the hospital database, 101 597 individuals met the eligibility criteria. Data analysis was performed from May through September 2020. Presentation to hospital with DFM after 28 weeks gestation. The primary outcome of this study was the incidence of stillbirth. Multivariate analysis was undertaken to determine the association between DFM and stillbirth, obstetric intervention, and other adverse outcomes, including being born small for gestational age (SGA) and a composite adverse perinatal outcome (at least 1 of the following: neonatal intensive care unit admission, severe acidosis [ie, umbilical artery pH <7.0 or base excess -12.0 mmol/L or less], 5-minute Apgar score <4, or stillbirth or neonatal death). The hypothesis being tested was formulated prior to data collection. Among 101 597 women with pregnancies that met the inclusion criteria, 8821 (8.7%) presented at least once with DFM and 92 776 women (91.3%) did not present with DFM (ie, the control population). Women presenting with DFM, compared with those presenting without DFM, were younger (mean [SD] age, 30.4 [5.4] years vs 31.5 [5.2] years; P < .001), more likely to be nulliparous (4845 women [54.9%] vs 42 210 women [45.5%]; P < .001) and have a previous stillbirth (189 women [2.1%] vs 1156 women [1.2%]; P < .001), and less likely to have a previous cesarean delivery (1199 women [13.6%] vs 17 444 women [18.8%]; P < .001). During the study period, the stillbirth rate was 2.0 per 1000 births after 28 weeks' gestation. Presenting with DFM was not associated with higher odds of stillbirth (9 women [0.1%] vs 185 women [0.2%]; adjusted odds ratio [aOR], 0.54; 95% CI, 0.23-1.26, P = .16). However, presenting with DFM was associated with higher odds of a fetus being born SGA (aOR, 1.14; 95% CI, 1.03-1.27; P = .01) and the composite adverse perinatal outcome (aOR, 1.14; 95% CI, 1.02-1.27; P = .02). Presenting with DFM was also associated with higher odds of planned early term birth (aOR, 1.26; 95% CI, 1.15-1.38; P < .001), induction of labor (aOR, 1.63; 95% CI, 1.53-1.74; P < .001), and emergency cesarean delivery (aOR, 1.18; 95% CI, 1.09-1.28; P < .001). The presence of DFM is a marker associated with increased risk for a fetus. This study's findings of a nonsignificantly lower rate of stillbirth among women with DFM may be reflective of increased community awareness of timely presentation to their obstetric care clinician when concerned about fetal movements and the benefits of tertiary level care guided by a clear clinical management protocol. However, DFM was associated with increased odds of an infant being born SGA, obstetric intervention, early term birth, and a composite of adverse perinatal outcomes.

Comparing the cerebro-placental to umbilico-cerebral Doppler ratios for the prediction of adverse neonatal outcomes in pregnancies complicated by fetal growth restriction

Objective The cerebroplacental ratio (CPR) has shown utility as a surrogate marker for fetal growth restriction and can be used to stratify the risk for adverse perinatal outcomes in affected pregnancies. However, recent studies suggest that its inverse, the umbilico-cerebral ratio (UCR), may be a better predictor of such outcomes. The aim of this study was to compare the prognostic accuracy of CPR to that of UCR Doppler in predicting short-term adverse perinatal outcomes in growth-restricted fetuses. Methods We conducted a secondary analysis using data from a prospective study on women referred for fetal growth ultrasounds between 26 and 36 weeks of gestation and with an EFW < 10th percentile by Hadlock standard. The CPR and UCR were converted into Z-scores adjusted for gestational age at ultrasound. Abnormal CPR was defined as Z-score below the 10th percentile for the gestational age and abnormal UCR as Z-score above the 90th percentile. We calculated sensitivity and specificity of the two Doppler parameters for predicting composite adverse perinatal outcome (APO) defined as the presence of any one of the following: umbilical cord arterial pH <7.10, Apgars at 5 min <7, NICU admission,grade III/IV intraventricular hemorrhage (IVH), neonatal seizure and death. Logistic regression analysis was performed, ROC curves plotted and the area under the ROC curve (AUC) were compared between CPR and UCR. Results Over the study period, there were 197 women meeting inclusion criteria, of which 27 (13.7%) had a composite adverse neonatal outcome. The sensitivity using CPR Z-score for predicting the composite APO was higher thanwas similar to using UCR Z-score (39.3% compared with 37%) for a similar specificity (94.7 versus 94.1), respectively. However, the positive predictive value (PPV) was higher for CPR (55% vs UCR 50%) and the negative predictive values (NPV) were similar. For a fixed false positive rate of 10%, the detection rates for adverse neonatal outcomes were 40% using either CPR or UCR. The AUC for CPR and UCR were 0.70 and 0.68, respectively. Conclusion This study did not find any advantage in utilizing the UCR over the CPR.

Cardiotocograph (CTG) changes and maternal and neonatal outcomes in chorioamnionitis and/or funisitis confirmed on histopathology

ObjectiveTo assess the cardiotocographic changes and maternal and neonatal outcomes in cases of chorioamnionitis and or funisitis confirmed on histopathology. Study DesignA retrospective analysis of histopathology reports confirming chorioamnionitis and/or funisitis was carried out from 2014 to 2020 in a single centre. The preterm births (<37 weeks) were excluded. The maternal records were reviewed to determine the maternal and neonatal outcomes such as the mode of delivery, intrapartum and postpartum complications, umbilical cord arterial pH, and admission to the special care baby unit (SCBU). The CTG features were analysed on admission and during the intrapartum period. The study was approved by the Audit and Clinical Effectiveness department within the centre. ResultsOut of the 57 cases of histologically confirmed chorioamnionitis and/or funisitis, 42 women (73.7 %) had intrapartum pyrexia and none of the mothers had an increased temperature at the point of fetal tachycardia (persistent increase in baseline fetal heart rate (FHR) by >10 % compared to the original baseline FHR). 43 (75.4 %) CTGs showed evidence of uterine tachysystole or hyperstimulation. 15 (26.3 %) cases had meconium stained amniotic fluid (MSAF). 54 (94.7 %) women had a caesarean section, and their babies were admitted to special care baby unit after delivery. 54 (94.7 %) babies had an umbilical artery of more than 7.1. 47 (87 %) of the women were readmitted with wound infection.All CTG traces showed a > 10 % increase in the baseline FHR and variable decelerations with overshoot were noted in cases where funisitis was confirmed in 25 cases (92.6 %). Loss of cycling was noted in 54 CTGs (94.7 %) and a sinusoidal pattern was identified in 27 (47.3 %). ConclusionRising (>10 %) baseline during labour along with loss of cycling with or without features of tachysystole or hyperstimulation should be considered in labour as features of ongoing chorioamnionitis. Chorioamnionitis confirmed on histopathology is associated with an increase in caesarean section rate due to fetal heart rate changes, increased risk of wound infection in mothers, and increased admission of the babies to SCBU.

Clinically relevant umbilical cord inflammation identified based on CD15-associated vasculitis patterning

IntroductionAcute funisitis, a granulocyte-related inflammation of the umbilical cord, is associated with chorioamnionitis and perinatal adverse events. However, there is no efficient procedure for detecting clinically relevant umbilical cord inflammation. The objective of this study was to identify such inflammation, based on immunohistochemical assessment of umbilical cord vasculitis patterns. MethodsAccordingly, 261 cases were retrieved from a single medical institute. Using the well-established granulocyte marker CD15, we developed a five-tier umbilical cord inflammation-scoring system. Additionally, previous morphological assessments from pathological reports were compared to the immunohistochemical findings. ResultsAnalysis of results based on our new scoring system revealed that severe umbilical phlebitis (score 3) was significantly associated with maternal inflammatory response and that severe umbilical arteriophlebitis (score 4) was correlated with low umbilical arterial blood pH, a feature linked to fetal mortality and morbidity. These results corresponded with and were validated by the morphology-based assessments. Additionally, immunohistochemical analysis revealed the clinical and pathological relevance of vitelline vasculitis, a recently proposed condition. We found that analyzing three umbilical cord sections enabled superior detection of severe umbilical vasculitis than analyzing two sections. However, whether these sections were sampled from multiple distant sites or a single localized site did not significantly affect the detection of clinically relevant inflammation. DiscussionCD15 immunohistochemistry is a potent tool for observing the patterns of clinically relevant umbilical vasculitis, especially in cases that were indeterminate according to morphology alone. Sampling three umbilical cord sections was an efficient procedure for addressing the spatial heterogeneity of umbilical cord inflammation. CD15 immunohistochemistry is a potent tool for observing the patterns of clinically relevant umbilical vasculitis, especially in cases that were indeterminate according to morphology alone. Sampling three umbilical cord sections was an efficient procedure for addressing the spatial heterogeneity of umbilical cord inflammation.

Risk factors and outcomes of abnormal bleeding after external cephalic version.

To present the consequences of and risk factors for abnormal bleeding after ECV (external cephalic version). We conducted a retrospective chart review at a single center in Japan. Abnormal bleeding was defined as vaginal bleeding and/or intrauterine hemorrhage. We descriptively assessed birth outcomes among women with abnormal bleeding, and investigated the risk factors using a logistic regression analysis. Of 477 women who received ECV, 39 (8.2%) showed abnormal bleeding, including 16 (3.4%) with intrauterine hemorrhage. Of the 16 women with intrauterine hemorrhage, 14 required emergency cesarean section; none experienced placental abruption, a low Apgar score at 5min (<7), or low umbilical cord artery pH (<7.1). Among 23 women who had vaginal bleeding without intrauterine hemorrhage, four cases underwent emergency cesarean section and one case of vaginal delivery involved placental abruption. The risk of abnormal bleeding was higher in women with a maximum vertical pocket (MVP) of <40mm in comparison to those with an MVP of >50mm (adjusted odds ratio [OR]: 3.48, 95% confidence interval [CI]: 1.23-9.90), as was higher in women with unsuccessful ECV than in those with successful ECV (aOR: 4.54, 95% CI: 1.95-10.6). A certain number of women who underwent ECV had abnormal bleeding, including vaginal bleeding and/or intrauterine hemorrhage, many of them resulted in emergency cesarean section. Although all of cases with abnormal bleeding had good birth outcomes, one case of vaginal bleeding was accompanied by placental abruption. Small amniotic fluid volume and unsuccessful ECV are risk factors for abnormal bleeding.

Clinical evaluation of electrohysterography as method of monitoring uterine contractions during labor: A propensity score matched study

ObjectiveElectrohysterography is a non-invasive technique to monitor uterine activity and has a significantly higher sensitivity compared to conventional external tocodynamometry. Whether this technique could lead to improved obstetrical outcomes is still unknown. In this propensity score matched study, clinical results of the first pilot implementing electrohysterography during labor were evaluated. The hypothesis tested is that electrohysterography will help to optimize uterine activity and thereby lead to fewer obstetric interventions. Secondary outcomes were Apgar score, arterial umbilical pH values, first stage labor duration, episiotomy rate and postpartum vaginal blood loss. Study designFrom November 2017 until October 2018, electrohysterography was introduced as a standard alternative for monitoring uterine activity in high-risk deliveries. It could be applied in case of induced labor, previous cesarean delivery, body mass index ≥30 kg/m2 or an inadequate external tocodynamometry monitoring. Outcomes were compared to a matched group of women in which external tocodynamometry was applied for uterine activity monitoring during labor. These women were identified using propensity scores. ResultsA total of 348 women received electrohysterography as standard method of uterine monitoring during labor. A match (1:1 ratio) was found for 317 women, resulting in a total population of 634 women. No significant differences were seen in obstetric interventions (i.e. cesarean deliveries and assisted vaginal deliveries) between the electrohysterography and tocodynamometry group (P = 0.80). No statistically significant differences were seen regarding the secondary outcomes. ConclusionsThis first pilot study implementing electrohysterography as monitoring method during labor in a high-risk population did not result in statistically significant differences regarding obstetric interventions, low Apgar scores or low umbilical artery pH values. Therefore, we suggest that electrohysterography causes no harm and we recommend further implementation and evaluation in clinical practice.

Associations of ultrasound estimated early mid pregnancy visceral and subcutaneous fat depths and early pregnancy BMI with adverse neonatal outcomes

This study investigated whether maternal central adiposity and body mass index (BMI) were associated with neonatal hypoglycemia and adverse neonatal outcomes. A cohort study was performed at Uppsala University Hospital, Sweden, between 2015 and 2018. Visceral and subcutaneous fat depths were measured by ultrasound at the early second-trimester anomaly scan in 2771 women giving birth to singleton infants. Body mass index was assessed in early pregnancy. Logistic regression models were performed. Adjustments were made for age, BMI (not in model with BMI as exposure), smoking, maternal country of birth, and parity. Outcomes were neonatal hypoglycemia (blood glucose concentration < 2.6 mmol/l), a composite of adverse neonatal outcomes (Apgar < 7 at 5 min of age, or umbilical artery pH ≤ 7.0, or admission to neonatal intensive care unit), and the components of the composite outcome. Visceral and subcutaneous fat depths measured by ultrasound in early mid pregnancy were not associated with any of the outcomes in adjusted analyses. For every unit increase in BMI, the likelihood of neonatal hypoglycemia increased by 5% (aOR 1.05, 95% CI 1.01–1.10), the composite outcome by 5% (aOR 1.05, 95% CI 1.01–1.08), and admission to neonatal intensive care unit by 6% (aOR 1.06, 95% CI 1.02–1.10).

Maternal pre-pregnancy body mass index and foetal acidosis in vaginal and caesarean deliveries: The Japan Environment and Children\u2019s Study

A high maternal body mass index (BMI) is associated with increased risks of asphyxia-related neonatal morbidity. We evaluated the association between maternal pre-pregnancy BMI and foetal acidosis while accounting for the mode of delivery. Participants from the Japan Environment and Children’s Study with singleton pregnancies after 22 weeks of gestation who gave birth during 2011–2014 were included. The participants (n = 71,799) were categorised into five groups according to the pre-pregnancy BMI: G1 (BMI < 18.5 kg/m2), G2 (18.5 to < 20.0 kg/m2), G3 (20.0 to < 23.0 kg/m2), G4 (23.0 to < 25.0 kg/m2), and G5 (≥ 25.0 kg/m2). Foetal acidosis was defined as umbilical artery pH (UmA-pH) < 7.20 or < 7.10. Multiple logistic regression analyses were used to evaluate the effect of pre-pregnancy BMI on foetal acidosis risk, accounting for the mode of delivery. In Japanese women, pre-pregnancy BMI ≥ 25.0 kg/m2 significantly increased the likelihood of foetal acidosis in newborns delivered vaginally. We found no association between pre-pregnancy BMI and foetal acidosis in newborns delivered via caesarean section. Counselling for body weight control before pregnancy and adequate management and selection of the mode of delivery in pregnant women with a high BMI who are in labour may be essential to avoid foetal acidosis.

Colloid preloading versus crystalloid preloading to prevent hypotension after spinal anesthesia for cesarean delivery: A protocol for systematic review and meta-analysis.

Background:Maternal hypotension is the most frequent complication of spinal anesthesia for cesarean delivery, and intravenous fluid preloading is a preventive measure. We aimed to assess the efficacy of colloids versus crystalloids for preloading to reduce the incidence of spinal anesthesia-induced hypotension and vasopressor requirement in healthy parturients during elective cesarean delivery.Methods:We searched the Cochrane Library, MEDLINE and EMBASE to identify all studies published to June, 2019, through OVID and PubMed. We included randomized controlled trials, comparing colloid preloading with crystalloid preloading in women having spinal anesthesia for cesarean delivery. Primary outcomes were the incidence of hypotension and vasopressor requirement. Secondary outcomes included nausea and/or vomiting, neonatal Apgar score, neonatal umbilical blood pH. We used standardized mean differences for expressing continuous outcomes and risk ratios for dichotomous outcomes. Random-effect model was performed to estimate the pooled risk ratios and standardized mean differences.Results:Thirty-three randomized controlled trials contributed data for this meta-analysis. Fewer women experienced hypotension in the colloid group compared with the crystalloid group (risk ratio: 0.72, 95% confidence interval: 0.63–0.82; 2566 women, 32 studies; P < .00001). The total ephedrine dose required was significantly lower with colloid preloading (standardized mean difference: −0.37, 95% CI: −0.64 to −0.09; 1472 women, 19 studies; P = .009). Colloid preloading was also associated with fewer phenylephrine requirement compared with crystalloid preloading (standardized mean difference: -0.54, 95% CI: -0.82 to -0.25; 169 women; P = .0002). The incidence of nausea and/or vomiting was significantly reduced with colloid preloading (risk ratio: 0.72, 95% CI: 0.55–0.95; 1601 women, 20 studies; P = .02). However, the incidence of 1-minute Apgar score < 7, umbilical artery pH < 7.2 and umbilical vein pH < 7.2 were not statistically different between groups.Conclusions:Colloid preloading is superior to crystalloid preloading in reducing the incidence of hypotension induced by spinal anesthesia and vasopressor requirement in the healthy parturients undergoing elective cesarean delivery.The PROSPERO registration number: CRD42018096402.

500 Obesity is associated with increased rates of umbilical artery pH< 7.1 at scheduled cesarean delivery

Limited data suggest obese women are at increased risk for decreased fetal umbilical artery (UA) pH prior to the onset of labor. Reduction in venous return from the weight of the abdominal wall and a decrease in maternal blood pressure in response to neuraxial anesthesia may contribute to hypoperfusion leading to a decreased UA pH. We hypothesize that obese women are at increased risk for UA pH <7.1 at time of non-labor cesarean delivery (CD) under neuraxial anesthesia. This multi-center retrospective cohort includes women who delivered a term, singleton, non-anomalous neonate from 2013-2019 via non-labor CD under neuraxial anesthesia. Multiple gestations and patients with suspected fetal growth restriction were excluded. Universal cord gas collection was routinely performed. Primary outcome was fetal UA pH <7.1 and base deficit ≥12 mmol in obese vs. non-obese gravidas. Secondary outcomes included NICU admission and other neonatal morbidities. Outcomes were assessed using multivariable logistic or linear regression and adjusted for age, race/ethnicity, insurance type, number of prior CDs, maternal medical problems, time from anesthesia placement to delivery and time from skin incision to delivery. Obesity was associated with younger maternal age, longer time from anesthesia placement and skin incision to delivery, non-White race, public insurance, higher order CD, tobacco use, hypertensive disorders and diabetes (all p<0.01). Obese patients were significantly more likely to have UA pH <7.1 (aOR 2.4, 95% CI 1.5-3.6; p<0.01) and UA base deficit ≥12 mmol (aOR 3.1, 95% CI 1.5-3.6; p<0.01). There was a significant trend toward UA pH <7.1 and base deficit ≥12 mmol with increasing class of obesity. We found no differences in secondary outcomes between groups. Maternal obesity is associated with increased rates of UA pH <7.1 and base deficit ≥12 mmol at time of non-labor CD under neuraxial anesthesia. These findings may prompt alterations in management of the obese parturient and may alter prediction of adverse outcomes in the neonate by fetal cord blood gas results.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

1067 Electronic FHR monitoring, pH and newborn outcomes – this is as good as it gets

To examine the relationship between umbilical artery (UA) cord gas values and fetal tolerance of labor and/or delivery. We hypothesized the existence of wide biologic variability in fetal tolerance of metabolic acidemia which, if present, would weaken a fundamental assumption underlying the use of EFHRM. A retrospective cohort study of term, singleton fetuses delivered between 2012 and 2020. Universal cord gases were collected. Umbilical cord gas values and Apgar scores were extracted. We calculated Spearman correlation coefficients (CC) and constructed ROC curves for UA pH and base excess (BE) as predictors of Apgar score. Our cohort included cord gas and Apgar scores from 29,787 deliveries. The statistical correlation between UA pH and BE and both 1 and 5 minute Apgar scores was weak or non-existent in both the group as a whole and in all pH range sub-groups (Table 1). ROC curve analysis of pH as a predictor of 5 minute Apgar >=7 showed only an acceptable discrimination (AUC= 0.75 95%CI 0.71-0.79, p< 0.01)) with a similar story for base excess (AUC=0.745 95%CI 0.708-0.782, p< 0.01). Subgroup analysis of deliveries with pH >7.2 or BE >-4 showed even poorer predictive ability (Figure 1). Of 8 newborns who underwent cooling for HIE, 3 (38%) had UA pH > 7.15. The use of EFHRM is predicated upon a documented correlation between certain FHR patterns and UA pH, and an arbitrary, presumed correlation between pH and fetal tolerance of labor/delivery, as reflected in newborn condition. To the extent that the latter relationship is invalid, the former correlation is irrelevant. Our data demonstrate a weak to absent correlation between metabolic acidemia and even short term fetal condition, confirming wide biologic variability in fetal tolerance of the hypoxic stress of labor and significantly weakening this latter assumption. No amount of future tweaking of FHR pattern interpretation is likely to result in improved newborn outcomes given this flaw in one fundamental assumption upon which FHRM is based.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Role of Neonatal Behavioral Neurological Assessment combined with magnetic resonance diffusion tensor imaging in evaluating white matter development in preterm infants.

To study the correlation of fractional anisotropy (FA) on magnetic resonance diffusion tensor imaging with Neonatal Behavioral Neurological Assessment (NBNA) score in preterm infants, and to study the role of FA in evaluating white matter development from the perspective of imaging. A prospective study was performed for 98 preterm infants who were admitted to the Neonatal Intensive Care Unit of the Third Affiliated Hospital of Zhengzhou University within 24 hours after birth from October 2016 to January 2020. According to the results of NBNA, they were divided into an abnormal group with 51 infants (NBNA score <37) and a normal group with 47 infants (NBNA score ≥37). The FA values of 10 regions of interest were collected and compared between the two groups. The correlations of FA value and umbilical arterial blood gas pH value with the NBNA score were analyzed. Compared with the normal group, the abnormal group had significantly lower FA value of the posterior limb of the internal capsule and umbilical arterial blood pH (P<0.05). The FA value of the posterior limb of the internal capsule and umbilical arterial blood pH were positively correlated with the NBNA score (r=0.584 and 0.604 respectively, P<0.001), and the FA value of the posterior limb of the internal capsule was positively correlated with umbilical arterial blood pH (r=0.426, P<0.05). The FA value of the posterior limb of the internal capsule can quantitatively reflect white matter development in preterm infants and is correlated with the NBNA score. The combination of the two indices can help to evaluate white matter development in preterm infants more accurately and objectively. Citation.

50 The Role of pCO2 in Umbilical Artery Gas Analysis: Predictive of Neonatal Morbidity?

The purpose of this study was to estimate the relationship between umbilical artery (UA) partial pressure of carbon dioxide (pCO2) at time of delivery and neonatal morbidity at term. If a strong relationship could be established, reflecting impaired fetal gas exchange, this would serve to more effectively and accurately predict neonatal morbidity shortly after delivery and inform resource allocation. This was a secondary analysis of a prospective cohort study of term, singleton, non-anomalous deliveries with universal cord gas collection from 2010 to 2014. Patients were included if they had paired and validated umbilical cord gases. The primary outcome was composite neonatal morbidity including neonatal death, hypoxic-ischemic encephalopathy, suspected sepsis, seizures, hypotension requiring vasopressors and hypothermia treatment. Hypercarbia was defined as UA pCO2 75th percentile. Multivariable logistic regression and the Zhang method were used to determine adjusted relative risk for neonatal morbidity in patients with and without hypercarbia and accounting for acidemia (UA pH<7.2). A receiver operating characteristic (ROC) curve was created to determine the predictive value of pCO2 for neonatal morbidity. Of 8580 patients in the cohort, 7608 had validated cord gas data. 697 (9.2%) had composite neonatal morbidity. Hypercarbia was associated with an increased risk of neonatal morbidity (RR 1.58 [95% CI 1.37-1.83]). However, after adjusting for acidemia, this relationship was no longer significant (aRR 1.04 [95% CI 0.86, 1.25]). UA pCO2 was less predictive of neonatal morbidity than UA pH (AUC of 0.57 [0.55,0.59] vs 0.64 [0.62,0.66], p<0.01). Hypercarbia, reflecting impaired fetal gas exchange, is associated with increased neonatal morbidity but is likely due to the presence of concomitant acidemia. UA pCO2 alone is a poor predictor of neonatal morbidity.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

454 Pregnancy outcome after cesarean section following a failed vacuum attempt

To compare pregnancy outcome of women who underwent cesarean section (CS) in second stage of labor, with or without a following failed vacuum extraction attempt (VE). A retrospective cohort study of women who underwent cesarean section during the second stage of labor in a single tertiary university affiliated medical center (2012-2019). Pregnancy outcome was compared for women who underwent cesarean section following a failed vacuum extraction to women who had cesarean section during the second stage of labor with no vacuum extraction attempt. Neonatal outcomes included umbilical artery pH less than 7.1, Apgar at 5 minutes < 7, hypoxemic ischemic encephalopathy and NICU admission. Maternal outcomes included duration of hospitalization, need for blood transfusion and need for re-surgery in 45 days. Overall, 88,375 women delivered during the study period. Of them, 120 women had a cesarean section following failed vacuum (study group). Another 551 women underwent cesarean section in the second stage of labor without VE attempt (control group). The groups were similar with regard to obstetrical and demographic characteristics. The rates of umbilical artery pH<7.1 (17.50% vs 6.53%, p<0.001), NICU admission (13.33% vs 2.90%, p<0.001), hypoxemic ischemic encephalopathy (5.83% vs 0.18%, p<0.001) and epicranial sub-aponeurotic hemorrhage (16.67% vs 2.18%, p<0.001) were significantly higher in the study group. No significant differences were found in maternal outcomes. In a sub-analysis including only labor with reassuring fetal heart tracing, failed vacuum attempt was associated with higher rate of NICU admission and epicranial hemorrhage (16.67% vs 3.13%, p=0.009, 27.78% vs. 3.41, p=0.001, respectively). Failed vacuum attempt is associated with a significant increased neonatal morbidity, but not increased maternal morbidityView Large Image Figure ViewerDownload Hi-res image Download (PPT)