Umbilical cord arterial lactate compared with pH for predicting neonatal morbidity at term

An Assessment of the Relationships Between Umbilical Cord Blood Gas Analysis, APGAR (Appearance, Pulse, Grimace, Activity, and Respiration) Scores, and Neonatal Outcomes

Introduction Intrapartum hypoxic-ischemic injury is a condition that significantly affects neonatal health and, therefore, needs to be attended to urgently. Umbilical cord blood gas analysis (BGA) results and APGAR (appearance, pulse, grimace, activity, and respiration) scores are commonly used to assess birth asphyxia and the severity of neonatal acidemia. In this context, this study was conducted to investigate the correlations of BGA results and APGAR scores with neonatal outcomes to determine the combined value of BGA results and APGAR scores in neonatal health assessment. Methods The sample of this retrospective cohort study consisted of 593 consecutive-term newborns delivered in a tertiary referral center in Turkey between January 2020 and December 2022. All newborns' maternal, delivery, and neonatal characteristics, BGA results, and APGAR scores were analyzed to determine correlations with composite adverse neonatal outcomes. The study's primary outcome was defined as the rate of the composite adverse neonatal outcomes, whereas the secondary outcomes were determined as the impact of maternal and neonatal characteristics on composite neonatal morbidity and the correlation between the one- and five-minute APGAR scores and umbilical cord BGA parameters. Results Of the 593 infants included in the study, 191 (32.2%) infants experienced composite adverse neonatal outcomes, primarily mechanical ventilation (47.7%), followed by respiratory distress/syndrome (35.6%). Significant correlations were detected between composite adverse neonatal outcomes and advanced maternal age (p = 0.025), cesarean section history (p < 0.001), preterm delivery (p < 0.001), lower one- and five-minute APGAR scores (p < 0.001 for both cases), and acidemia severity (p = 0.007). However, the correlations between BGA parameters and APGAR scores were weak (r < 0.2). Conclusion This study investigated the correlations between neonatal mortality and morbidity and maternal factors, delivery characteristics, and fetal features, including one- and five-minute APGAR scores and BGA parameters. Nevertheless, weak correlations between BGA parameters and APGAR scores warrant further comprehensive prospective studies.

Umbilical Artery Cord Gas Abnormalities in the Presence of a Nuchal Cord in Term Singleton Pregnancies: A Cohort Study

OBJECTIVE

 The clinical significance of nuchal cord (NC) at the time of delivery is unclear. Studies have found that NC is associated with lower umbilical artery (UA) pH. Since fetal hypercarbia precedes respiratory acidosis, we hypothesize UA pCO2 is elevated in neonates with NC at the time of delivery.

STUDY DESIGN

 This is a secondary analysis of a prospective cohort study of women with full-term singleton pregnancies admitted in labor or for induction of labor at an institution with a universal umbilical cord gas policy. We compared patients with NC at the time of delivery to those without NC. Women were excluded if they did not have validated UA gases, had a major fetal anomaly, or had an intrauterine fetal demise. The primary outcome of the study was UA pCO2. Secondary outcomes were other components of UA gas and neonatal morbidity composite. Baseline characteristics were compared utilizing chi-square or Fisher's exact test or the Student's t-test. UA gas parameters were compared using the Kruskal-Wallis test. Multivariable logistic regression was utilized to adjust for confounders.

RESULTS

 Of the 8,580 study participants, 7,608 had validated umbilical cord gases. The incidence of NC in the population was 24.15% (n = 1,837). UA pCO2 was higher in those with NC than without (58 mm Hg [53-64] vs. 55 mm Hg [50-60], p < 0.01). There was a greater odds of hypercarbia in the NC group (pCO2 > 65 mmHg; adjusted odds ratio [aOR]: 1.97, 95% confidence interval [CI]: 1.72-2.25, p < 0.01). Additionally, the NC group was more likely to be mildly acidemic (pH < 7.2, aOR: 1.74, 95% CI: 1.51-2.01, p < 0.01). There was no difference in composite neonatal morbidity between the groups.

CONCLUSION

 NC is associated with an increased risk of hypercarbia and acidemia. However, this is not associated with increased risk of neonatal morbidity.

KEY POINTS

· Nuchal cord is associated with an increased risk of hypercarbia and mild acidemia.. · Nuchal cord is not likely associated with neonatal morbidity.. · Neonatal management should not be altered due to the presence of a nuchal cord at delivery..

The Risk of Neonatal Morbidity in Umbilical Artery Hypercarbia and Respiratory Acidosis

OBJECTIVE

 To test the hypothesis that elevated umbilical artery (UA) partial pressure of carbon dioxide (pCO2) is associated with neonatal morbidity and to compare the risk of neonatal morbidity with different patterns of UA acidosis.

STUDY DESIGN

 This was a secondary analysis of a prospective cohort of term, singleton, nonanomalous deliveries with universal cord gas collection. The primary outcome was composite neonatal morbidity. Multivariable logistic regression was used to determine the relative risk (RR) for neonatal morbidity in patients with and without UA hypercarbia. A receiver operating characteristic curve determined the predictive value of pCO2 for neonatal morbidity. An additional multivariable logistic regression was used to evaluate the risk of neonatal morbidity in different patterns of UA acidosis.

RESULTS

 UA hypercarbia was associated with an increased risk of neonatal morbidity (RR: 2.56, 95% confidence interval [CI]: [2.07, 3.17]). After adjusting for UA acidemia, this association remained significant (adjusted RR: 1.39, 95% CI: [1.05, 1.83]). UA pCO2 was less predictive of neonatal morbidity than UA pH (area under the curve [AUC]: 0.65, 95% CI: [0.62, 0.68] vs. AUC: 0.72, 95% CI: [0.69, 0.75], p < 0.01). The odds ratios for neonatal morbidity for respiratory, mixed, and metabolic acidosis compared with normal cord gases were 1.48 (95% CI: [0.88, 2.49]), 6.41 (95% CI: [3.68, 11.17]), and 7.49 (95% CI: [5.76, 9.72]), respectively, p-trend < 0.01.

CONCLUSION

 UA hypercarbia is an independent predictor of neonatal morbidity, even in the setting of concomitant UA acidemia. UA mixed and metabolic acidosis carry significantly greater risk of neonatal morbidity compared with respiratory acidosis.

KEY POINTS

· UA pCO2 is associated with neonatal morbidity.. · UA respiratory acidosis is the UA cord gas pattern least associated with neonatal morbidity.. · UA pH is a superior predictor of neonatal morbidity compared with UA pCO2..

Association between Elevated Intrauterine Resting Tone during Labor and Neonatal Morbidity

OBJECTIVE

 Internal contraction monitoring provides a quantitative assessment of intrauterine resting tone. During the course of labor, elevated intrauterine resting tone may be identified. We hypothesized that elevated intrauterine resting tone could lead to compression of the spiral arteries, thus limiting uterine blood flow and resulting in neonatal compromise. Therefore, our objective was to assess the association between elevated resting tone during labor and neonatal morbidity.

STUDY DESIGN

 This was a secondary analysis of a prospective cohort study of singleton deliveries at ≥37 weeks of gestation. Patients with ruptured membranes and an intrauterine pressure catheter in place for at least 30 minutes prior to delivery were included. Intrauterine resting tone was calculated as the average baseline pressure between contractions during the 30 minutes prior to delivery. The study group had elevated intrauterine resting tone, defined as intrauterine resting tone ≥75th percentile (≥12.3 mm Hg). Primary outcome was composite neonatal morbidity: hypoxic-ischemic encephalopathy, hypothermia treatment, intubation, seizures, umbilical arterial pH ≤7.1, oxygen requirement, or death. Secondary outcomes included umbilical artery pH <7.2, lactate ≥4 mmol/L, and rates of neonatal intensive care unit admission.

RESULTS

 Of the 8,580 patients in the cohort, 2,210 (25.8%) met the inclusion criteria. The median intrauterine resting tone was 9.7 mm Hg (interquartile range: 7.3-12.3 mm Hg). Elevated resting tone was associated with a shorter median duration of the first stage of labor (10.0 vs. 11.0 hours, p < 0.01) and lower rates of labor induction and oxytocin augmentation (p < 0.01). Neonatal composite morbidity was higher among patients with elevated intrauterine resting tone (5.1 vs. 2.9%, p = 0.01). After adjusting for chorioamnionitis and amnioinfusion, elevated intrauterine resting tone was associated with increased risk of neonatal morbidity (adjusted odds ratio: 1.70, 95% confidence interval: 1.06-2.74).

CONCLUSION

 Our findings suggest that elevated intrauterine resting tone is associated with increased risk of neonatal composite morbidity.

KEY POINTS

· Higher intrauterine resting tone is associated with increased risk of neonatal morbidity.. · Elevated intrauterine tone can negatively impact umbilical artery pH and lactate levels.. · If elevated intrauterine pressure is noted, we recommend close monitoring of fetal status..

Pain control and neonatal outcomes in 211 women under epidural anesthesia during childbirth at high altitude in Qinghai, China

Background

High altitudes are characterized by low-pressure oxygen deprivation. This is further exacerbated with increasing altitude. High altitudes can be associated with reduced oxygenation, which in turn, can affect labor, as well as maternal and fetal outcomes. Epidural anesthesia can significantly relieve labor pain. This study aimed to assess the effects of elevation gradient changes at high altitude on the analgesic effect of epidural anesthesia, labor duration, and neonatal outcomes.

Methods

We divided 211 women who received epidural anesthesia into groups according to varying elevation of their residence (76 in Xining City, mean altitude 2,200 m; 63 in Haibei Prefecture, mean altitude 3,655 m; and 72 in Yushu Prefecture, mean altitude 4,493 m). The analgesic effect was assessed using a visual analog scale (VAS). Labor duration was objectively recorded. The neonatal outcome was assessed using Apgar scores and fetal umbilical artery blood pH.

Results

VAS scores among the three groups did not differ significantly (p > 0.05). The neonatal Apgar scores in descending order were: Xining group > Haibei group > Yushu group (p < 0.05). The stage of labor was similar among the three groups (p > 0.05). Fetal umbilical artery blood pH in descending order were: Xining group > Haibei group > Yushu group (p < 0.05).

Conclusion

Elevation gradient changes in highland areas did not affect the efficacy of epidural anesthesia or labor duration. However, neonatal outcomes were affected.

Umbilical arterial lactate levels after normal vaginal and elective cesarean delivery: The role of a longer active second stage most significant in high levels after vaginal delivery

AIM

To evaluate umbilical arterial lactate concentrations after spontaneous vaginal delivery and after elective Cesarean delivery, and to study the simultaneous effects of maternal and obstetric variables in high lactate levels in vaginally delivered healthy term singletons.

METHODS

The birth register study included information about the umbilical artery lactate values and clinical perinatal data from 7723 women and their singleton newborns (7301 spontaneous vaginal and 422 elective cesareans) from Kuopio University Hospital, Finland. High lactate levels were evaluated more extensively among healthy term neonates (N = 6541), to evaluate high levels after normal vaginal labors.

RESULTS

The mean lactate level was significantly lower after elective cesarean compared to vaginal delivery (2.42 [0.94] vs. 3.56 [1.62] mmol/l; p < 0.0001). Consequently, the 90th percentile limit values were 3.60 and 5.80 mmol/L. Among healthy term newborns born vaginally, higher lactate values (≥5.80 mmol/L) were independently associated with a longer duration of the active second stage of labor (ORs 1.91-10.97) and duration of ruptured fetal membranes (ORs 1.36-2.46), higher gestational age at birth (ORs 1.41-1.86), null parity (OR 2.17), maternal infection (OR 1.81) and short maternal stature (OR 1.45). We report 90th/95th limits for umbilical arterial lactate values in relation to the various durations of labors for term newborns who are delivered by the vaginal route.

CONCLUSIONS

Even though the high umbilical lactate levels may indicate serious birth asphyxia, levels after vaginal birth reflect the physiological stress and subclinical transient asphyxia frequently seen in normal vaginal deliveries.

Incidence of encephalopathy and comorbidity in infants with perinatal asphyxia: a comparative prospective cohort study

Background

Programs that aim to improve the detection hypoxic-ischemic encephalopathy (HIE) should establish which neonates suffering from perinatal asphyxia need to be monitored within the first 6 h of life.

Method

An observational prospective cohort study of infants with gestational age ≥35 weeks, and above 1,800g, were included according to their arterial cord pH value (ApH): ≤7.00 vs. 7.01-7.10. Data was collected including obstetrical history, as well as neonatal comorbidities, including the presence of HIE, that happened within 6 h of life. A standardized neurological exam was performed at discharge.

Results

There were 9,537 births; 176 infants with ApH 7.01-7.10 and 117 infants with ApH ≤7.00. All 9 cases with moderate-to-severe HIE occurred among infants with ApH ≤7.00. The incidence of global and moderate-severe HIE was 3/1,000 and 1/1,000 births, respectively. Outcome at discharge (abnormal exam or death) showed an OR 12.03 (95% CI 1.53, 94.96) in infants with ApH ≤7.00 compared to ApH 7.01-7.10 cohort. Ventilation support was 5.1 times (95% CI 2.87, 9.03) more likely to be needed by those with cord ApH ≤7.00 compared to those with ApH 7.01-7.10, as well as hypoglycemia (37% vs. 25%; p = 0.026). In 55%, hypoglycemia occurred despite oral and/or intravenous glucose administration had been already initiated.

Conclusions

Cord pH 7.00 might be a safe pH cut-off point when developing protocols to monitor infants born with acidemia in order to identify infants with moderate or severe HIE early on. There is non-negligible comorbidity in the ApH ≤7.00 cohort, but also in the 7.01-7.10 cohort.

The effect of fetal hypoxia on myeloperoxidase levels in cord blood: a prospective study

BACKGROUND

We aimed to compare myeloperoxidase (MPO) levels in cord blood samples of mothers with and without perinatal hypoxia, since fetal hypoxia results in decreased pH, base excess, and an increase in pCO2 and lactate levels.

METHODS

We enrolled 42 pregnant women to this cross-sectional analytic study if they had met following criteria: uneventful gestational follow-ups, no known chronic or pregnancy-associated diseases, a BMI of <29.9, a singleton pregnancy, those with pregnancy over 34 weeks. The exclusion criteria for the study and control groups were as follows: presence of multiple pregnancies, fetal abnormality, any disease diagnosed before or during antenatal follow-up e.g., diabetes, hypertension, thyroid dysfunction, uncontrolled endocrine disease or abnormal kidney function, autoimmune disease, chronic inflammatory diseases, IUGR, preeclampsia), maternal age below 18 or above 35, intrauterine exitus, pregnancy with assisted reproductive technique, alcohol or smoking addiction, and any chronic drug use. The subjects were 1:1 randomized to either hypoxic newborns (N.=21) and those in the control group (N.=21) and their myeloperoxidase levels were measured from cord blood samples. Results were expressed as U/L. Patient data regarding age, gestation, parity, birth weight, birth length, APGAR scores, and neonatal complications were collected. All the women signed written informed consent forms and accepted verbal consent before being included in the study.

RESULTS

The mean age of the study population was 26.9±5.3 years. The mean BMI was 28.3±3.5 kg/m2. For the hypoxic group, 21 newborns with cord blood below 7.25 were included in the study group. The bloods with pH above 7.25 formed the control group. Mean pH and five (5) minute APGAR scores were found to be significantly lower in the study group, while base excess (BE) was found to be significantly higher. In this study, we compared the MPO levels of hypoxic newborns and those in the control group, and we did not find a significant difference between the two groups (P=0.147). Pearson Correlation Analysis is at -0.566 with P value (0.008) showing significant negative correlation between MPO and pH in the study group.

CONCLUSIONS

We found that MPO values are negatively correlated with cord blood pH among newborns diagnosed with fetal hypoxia.

Effect of maternal oxygen supplementation for parturient undergoing elective cesarean section by high-flow nasal oxygen compared with room air on fetal acidemia: study protocol for a randomized controlled trial

BACKGROUND

Maternal oxygen supplementation is usually used as an intrauterine resuscitation technique to prevent fetal hypoxia and acidemia during delivery. However, there has been a great deal of controversy regarding the effects of prophylactic maternal oxygen during cesarean section, during which the incidence of fetal acidemia seems to be higher compared with that during labor. High-flow nasal oxygen (HFNO) can improve oxygenation better in patients with high-flow oxygen airflow. The purpose of this study is to determine whether maternal oxygen supplementation with HFNO has a positive effect on fetal acidemia during cesarean section through umbilical arterial blood gas analysis.

METHOD

This prospective, single-center, randomized, double-blinded trial will enroll 120 patients undergoing cesarean section. Participants will be randomly assigned to the HFNO group or air group at a 1:1 ratio. For parturients in the HFNO group, the flow rate is 40L/min, and the oxygen is heated to 37℃ with humidity 100% oxygen concentration through the Optiflow high-flow nasal oxygen system. And for the air group, the flow rate is 2 L/min with an air pattern through the same device. The primary outcome was umbilical artery (UA) lactate. Secondary outcomes include UA pH, PO2, PCO2, BE, the incidence of pH < 7.20 and pH < 7.10, Apgar scores at 1 and 5 min, and neonatal adverse outcomes.

DISCUSSION

Our study is the first trial investigating whether maternal oxygen supplementation with HFNO can reduce the umbilical artery lactate levels and the incidence of fetal acidemia in cesarean section under combined spinal-epidural anesthesia.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05921955. Registered on 27 June 2023.

Association between Serum Lactate and Morbidity and Mortality in Neonates: A Systematic Review and Meta-Analysis

OBJECTIVE

Lactate is a marker of hypoperfusion in critically ill patients. Whether lactate is useful for identifying and stratifying neonates with a higher risk of adverse outcomes remains unknown. This study aimed to investigate the association between lactate and morbidity and mortality in neonates.

METHODS

A meta-analysis was performed to determine the association between blood lactate levels and outcomes in neonates. Ovid MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov were searched from inception to 1 May 2021. A total of 49 observational studies and 14 data accuracy test studies were included. The risk of bias was assessed using the Newcastle-Ottawa Scale for observational studies and the QUADAS-2 tool for data accuracy test studies. The primary outcome was mortality, while the secondary outcomes included acute kidney injury, necessity for renal replacement therapy, neurological outcomes, respiratory morbidities, hemodynamic instability, and retinopathy of prematurity.

RESULTS

Of the 3184 articles screened, 63 studies fulfilled all eligibility criteria, comprising 46,069 neonates. Higher lactate levels are associated with mortality (standard mean difference, -1.09 [95% CI, -1.46 to -0.73]). Using the estimated sensitivity (0.769) and specificity (0.791) and assuming a prevalence of 15% for adverse outcomes (median of prevalence among studies) in a hypothetical cohort of 10,000 neonates, assessing the lactate level alone would miss 346 (3.46%) cases (false negative) and wrongly diagnose 1776 (17.76%) cases (false positive).

CONCLUSIONS

Higher lactate levels are associated with a greater risk of mortality and morbidities in neonates. However, our results do not support the use of lactate as a screening test to identify adverse outcomes in newborns. Research efforts should focus on analyzing serial lactate measurements, rather than a single measurement.

Umbilical cord gas analysis: clinical implications of a comprehensive, contemporary determination of normal ranges

BACKGROUND

Umbilical cord gases are often used to assess the impact of labor and delivery on the fetus. However, no large series exists that reflects contemporary obstetrical practice or that analyzed blood gas ranges by route of delivery. Baseline, prelabor acid-base status in the human fetus is also poorly defined, rendering the assessment of blood gas changes during labor difficult.

OBJECTIVE

This study aimed to define normal umbilical cord gas and lactate values, stratified by mode of delivery, in a large contemporary series in which universal umbilical cord gas evaluation was dictated by protocol.

STUDY DESIGN

This was a retrospective cohort study. We analyzed the umbilical cord gas and lactate data of an unselected population of infants born between March 2012 and April 2022 at a large teaching hospital. These values were then analyzed by mode of delivery and, for cesarean deliveries, by indication for cesarean delivery and type of anesthesia. Umbilical cord gas values from infants delivered by elective cesarean delivey under general anesthesia without labor were considered representative of baseline, prelabor values.

RESULTS

Data were available for 45,475 infants. The median arterial pH values and interquartile ranges for vaginal births, elective cesarean deliveries without labor, and cesarean deliveries performed for fetal heart rate concerns were 7.27 (0.09), 7.27 (0.06), and 7.25 (0.09), respectively. Arterial lactate values for these same 3 groups were 4.1 (2.5), 2.5 (1.2), and 4.0 (2.8) mmoles/L, respectively. Because of the very large sample size, most comparisons yielded differences that were statistically significant, but clinically irrelevant. Of all the infants, 14% had an arterial pH <7.20; a pH value of 7.1 represents 2 standard deviations from the mean.

CONCLUSION

This large, population-based study of umbilical cord gas and lactate levels in an unselected population, stratified by delivery mode, represents a previously unavailable benchmark for the evaluation of umbilical cord gases. Arterial umbilical cord pH values for infants delivered by elective caesarean delivery without labor (median pH 7.28) reflect a lower prelabor fetal pH baseline than previously assumed. This finding, coupled with our determination that a 2 standard deviation below normal pH limit of 7.1, instead of the historic arbitrary pH of 7.2 threshold, helps to explain the poor positive predictive value of electronic fetal heart rate monitoring, a test designed to detect arterial pH levels that have fallen from an assumed baseline near pH 7.4 to an assumed potentially injurious pH level of <7.2. Uncomplicated labor, even when prolonged, does not generally lead to a clinically significant cumulative hypoxic stress to the human fetus. These findings, along with our determination that there is no difference in the acid-base status among infants delivered by cesarean delivery for fetal heart rate concerns, help to explain the failure of current approaches in labor and delivery management to reduce the rates of neonatal hypoxic-ischemic encephalopathy and cerebral palsy, conditions that almost always reflect developmental events rather than the effects of labor on the fetus.

A comparison of criteria for defining metabolic acidemia in live-born neonates and its effect on predicting serious adverse neonatal outcomes

BACKGROUND

Metabolic acidemia is a known risk factor for serious adverse neonatal outcomes in both preterm and term infants.

OBJECTIVE

This study aimed to evaluate the clinical significance of delivery umbilical cord gas measurements with regard to serious adverse neonatal outcomes, and to determine if distinct thresholds for defining metabolic acidemia differ in their ability to predict such adverse neonatal complications.

STUDY DESIGN

This is a retrospective cohort study of singleton live-born deliveries between January 2011 and December 2019. Stratification according to gestational age at birth (≥35 and <35 weeks of gestation) was performed, and comparisons of maternal characteristics, obstetrical complications, intrapartum events, and adverse neonatal outcomes were made between neonates with metabolic acidemia and those without. Metabolic acidemia (based on delivery umbilical cord gas analyses) was defined using both American College of Obstetricians and Gynecologists and Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria. The primary outcome of interest was hypoxic-ischemic encephalopathy requiring whole-body hypothermia.

RESULTS

A total of 91,694 neonates born at ≥35 weeks of gestation met the inclusion criteria. By American College of Obstetricians and Gynecologists criteria, 2659 (2.9%) infants had metabolic acidemia. Neonates with metabolic acidemia were at markedly increased risk for neonatal intensive care unit admission, seizures, need for respiratory support, sepsis, and neonatal death. Metabolic acidemia by American College of Obstetricians and Gynecologists criteria was associated with an almost 100-fold increased risk of hypoxic-ischemic encephalopathy requiring whole-body hypothermia (relative risk, 92.69; 95% confidence interval, 64.42-133.35) in neonates born at ≥35 weeks of gestation. Diabetes mellitus, hypertensive disorders of pregnancy, postterm deliveries, prolonged second stages, chorioamnionitis, operative vaginal deliveries, placental abruption and cesarean deliveries were associated with metabolic acidemia in neonates born ≥ 35 weeks of gestation. The highest relative risk was in those diagnosed with placental abruption (relative risk, 9.07; 95% confidence interval, 7.25-11.36). The neonatal cohort born <35 weeks of gestation had similar findings. When comparing those infants born ≥ 35 weeks of gestation with metabolic acidemia by American College of Obstetricians and Gynecologists criteria vs Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria, the Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria identified more neonates at risk for serious adverse neonatal outcomes. In particular, 4.9% more neonates were diagnosed with metabolic acidemia, and 16 more term neonates were identified as requiring whole-body hypothermia. Mean 1-minute and 5-minute Apgar scores were similar and reassuring among neonates born at ≥35 weeks of gestation with and without metabolic acidemia as defined by both American College of Obstetricians and Gynecologists and Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria (8 vs 8 and 9 vs 9, respectively; P<.001). Sensitivity and specificity were 86.7% and 92.2%, respectively, with the Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria, and 74.2% and 97.2% with the American College of Obstetricians and Gynecologists criteria.

CONCLUSION

Infants with metabolic acidemia identified on cord gas collection at delivery are at considerably greater risk of serious adverse neonatal outcomes, including an almost 100-fold increased risk of hypoxic-ischemic encephalopathy requiring whole-body hypothermia. Use of the more sensitive Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria for defining metabolic acidemia identifies more neonates born at ≥35 weeks of gestation at risk for adverse neonatal outcomes, including hypoxic-ischemic encephalopathy requiring whole-body hypothermia.

Maternal and umbilical cord blood lactate for predicting perinatal death: a secondary analysis of data from a randomized controlled trial

BACKGROUND

In high resource settings, lactate and pH levels measured from fetal scalp and umbilical cord blood are widely used as predictors of perinatal mortality. However, the same is not true in low resource settings, where much of perinatal mortality occurs. The scalability of this practice has been hindered by difficulty in collecting fetal scalp and umbilical blood sample. Little is known about the use of alternatives such as maternal blood, which is easier and safer to obtain. Therefore, we aimed to compare maternal and umbilical cord blood lactate levels for predicting perinatal deaths.

METHODS

This was secondary analysis of data from a randomized controlled trial assessing the effect of sodium bicarbonate on maternal and perinatal outcomes among women with obstructed labour at Mbale regional referral hospital in Eastern Uganda. Lactate concentration in maternal capillary, myometrial, umbilical venous and arterial blood was measured at the bedside using a lactate Pro 2 device (Akray, Japan Shiga) upon diagnosis of obstructed labour. We constructed Receiver Operating Characteristic curves to compare the predictive ability of maternal and umbilical cord lactate and the optimal cutoffs calculated basing on the maximal Youden and Liu indices.

RESULTS

Perinatal mortality risk was: 102.2 deaths per 1,000 live births: 95% CI (78.1-130.6). The areas under the ROC curves were 0.86 for umbilical arterial lactate, 0.71 for umbilical venous lactate, and 0.65 for myometrial lactate, 0.59 for maternal lactate baseline, and 0.65 at1hr after administration of bicarbonate. The optimal cutoffs for predicting perinatal death were 15 0.85 mmol/L for umbilical arterial lactate, 10.15mmol/L for umbilical venous lactate, 8.75mmol/L for myometrial lactate, and 3.95mmol/L for maternal lactate at recruitment and 7.35mmol/L after 1 h.

CONCLUSION

Maternal lactate was a poor predictor of perinatal death, but umbilical artery lactate has a high predictive value. There is need for future studies on the utility of amniotic fluid in predicting intrapartum perinatal deaths.

Considering the Effects and Maternofoetal Implications of Vascular Disorders and the Umbilical Cord

The umbilical cord is a critical anatomical structure connecting the placenta with the foetus, fulfilling multiple functions during pregnancy and hence influencing foetal development, programming and survival. Histologically, the umbilical cord is composed of three blood vessels: two arteries and one vein, integrated in a mucous connective tissue (Wharton's jelly) upholstered by a layer of amniotic coating. Vascular alterations in the umbilical cord or damage in this tissue because of other vascular disorders during pregnancy are worryingly related with detrimental maternofoetal consequences. In the present work, we will describe the main vascular alterations presented in the umbilical cord, both in the arteries (Single umbilical artery, hypoplastic umbilical artery or aneurysms in umbilical arteries) and the vein (Vascular thrombosis, aneurysms or varicose veins in the umbilical vein), together with other possible complications (Velamentous insertion, vasa praevia, hypercoiled or hypocoiled cord, angiomyxoma and haematomas). Likewise, the effect of the main obstetric vascular disorders like hypertensive disorders of pregnancy (specially pre-eclampsia) and chronic venous disease on the umbilical cord will also be summarized herein.

Clinical Scoring Systems in the Newborn Calf: An Overview

Simple Summary

Clinical scores are gaining increasing popularity in veterinary medicine thanks to their multiple advantages, which include quickness, ease, and convenience of use. This review discusses the applications of some already-known clinical scores in newborn calf management at birth and during the first weeks of age. Clinical scores are employed to assess newborn calf viability and to diagnose and monitor neonatal calf diarrhea and respiratory diseases, helping the clinician promptly recognize calves needing medical assistance. This review discusses limitations pertaining to their use and encourages efforts towards a greater consistency in definition and validation.

Abstract

A scoring system is an instrument that enables the scorers, including farmers, technicians, and veterinarians, to adopt a systematic approach for diagnosis or monitoring, as it decreases bias and confounding and increases objectivity. Practically, it is a number assigned to a patient that correlates with a probability that a diagnosis can be confirmed or that a specific outcome will follow. This article examines the clinical scores designed or adapted to bovine medicine that aim to assess newborn calf viability and to diagnose and monitor neonatal calf diarrhea and respiratory diseases, helping the clinician promptly recognize calves needing medical assistance. Despite the large number of clinical scores described in the literature, these are still barely used in farm animal practice; possibly, the complexity of the scores and missing recommendations for intervention are reasons for their lack of popularity as well as the crosswise lack of consistency among scores designed for the same purpose. Further research is needed in this regard to increase scores validation and encourage their application in bovine calf neonatology.

A novel scoring system (YASHMA) predicting brain injury in asphyxiated newborns

BACKGROUND

Hypoxic-ischemic encephalopathy is a complication of adverse intrapartum events and birth asphyxia resulting in brain injury and mortality in late preterm and term newborns.

OBJECTIVES

In this study, we aimed to predict brain damage on magnetic resonance imaging (MRI) with a new scoring system.

METHODS

Yieldly And Scorable Holistic Measuring of Asphyxia (YASHMA) is generated for detection of brain injury in asphyxiated newborns. Total scores were calculated according to scores of birth weight, gestation weeks, APGAR scores at first and fifth minutes, aEEG patterns and epileptic status of patients. The major outcome of the scoring system was to determine correlation between poor scores and neonatal brain injury detected on MRI.

RESULTS

In hypothermia group with brain injury, low gestational weeks and lowest APGAR scores, abnormal aEEG findings were statistically different from others. YASHMA scores were statistically significant with high sensitivity, specificity, AUC and 95% confidence interval values.

CONCLUSIONS

YASHMA scoring system is feasible and can be suggestive for detecting brain injury in low-income countries.

Comparative study of dinoprostone and misoprostol for induction of labor in patients with premature rupture of membranes after 35 weeks

The modalities of induction of labor in the event of premature rupture of membranes are controversial. The main purpose of this study was to compare the modalities of delivery after the use of dinoprostone or misoprostol for labor induction in the preterm rupture of membranes after 35 weeks in women with an unfavorable cervix. We then studied maternal and fetal morbidity for the two drugs. Retrospective, single-center, comparative cohort study in a level 3 maternity unit in France from 2009 to 2018 comparing vaginal administration of misoprostol 50 µg every six hours (maximum 150 µg) and administration of dinoprostone 10 mg, a slow-release vaginal insert, for 24 h (maximum 20 mg), for labor induction in the preterm rupture of membranes after 35 weeks in women with an unfavorable cervix (Bishop score < 6). We included 904 patients, 656 in the misoprostol group and 248 in the dinoprostone group. Vaginal delivery rate was significantly higher in the dinoprostone group (89% vs. 82%, p = 0.016). There were more cesarean sections for abnormal fetal heart rate in the misoprostol group (p = 0.005). The time interval from induction to the beginning of the active phase of labor and the duration of labor were shorter in the misoprostol group than in the dinoprostone group (437 min vs. 719 min, p < 0.001 and 335 min vs. 381 min, p = 0.0023, respectively). Maternal and neonatal outcomes were not significantly different in the two groups. Vaginal dinoprostone used for labor induction in preterm rupture of membranes seems to be more effective for vaginal delivery than vaginal misoprostol (50 µg).

Umbilical Cord Blood Acid-Base Parameters and Lactate as Predictors of Subsequent Meconium Aspiration Syndrome in Neonates

Meconium aspiration syndrome (MAS) in neonates born through meconium-stained amniotic fluid (MSAF) causes significant morbidity and mortality. Early recognition of at-risk neonates could help optimize treatment. The aim was to determine predictive characteristics of cord blood pH, base deficit and lactate with subsequent MAS. Receiver operating characteristic (ROC) curves with area under curve (AUC) were estimated. Among 231 MSAF complicated pregnancies, 25 (10.8%) had MAS. Mean cord pH was significantly lower in neonates with MAS compared to those without MAS (7.15 ± 0.11 vs. 7.26 ± 0.07; p < 0.001). Median lactate between the two groups [5.6 (7.5, 3.7) vs. 2.7 (4.5, 2.0)] and base deficit [-10.6 (-13.2, -4.2) vs. -3.7 (-6.3, -2.6)] also differed significantly (p = 0.01). ROC curve area for cord lactate, pH, and base deficit were 0.81, 0.79, and 0.75, respectively. The predictive cutoff values for pH, lactate, and base deficit were 7.20, 3.55 mmol/L, and -5.3 mmol/L, respectively.

A Height-Based Dosing Algorithm of Bupivacaine in Spinal Anesthesia for Decreasing Maternal Hypotension in Cesarean Section Without Prophylactic Fluid Preloading and Vasopressors: A Randomized-Controlled Non-Inferiority Trial

Background

There is a high incidence of maternal hypotension in spinal anesthesia for cesarean section. The aim of the study is to investigate whether there is a height-based dosing algorithm of bupivacaine that provides adequate anesthesia with less maternal hypotension.

Methods

There were 2 groups of 280 parturients who did not receive prophylactic fluid preloading: Test and Conventional group. In Test group, a height based dosing algorithm was used to confirm the dose of bupivacaine in parturients without prophylactic vasopressors. In the Conventional group, a constant dose of bupivacaine was used. The complications and quality of anesthesia were evaluated.

Results

In the Conventional group, the shorter participants had higher incidence of hypotension, faster sensory block time, and more participants with complete motor block (p = 0.030, 2.957 × 10^-14, and 0.012). In the Test group, the incidence of hypotension, sensory block time, and number of participants with complete motor block did not change with height (p = 0.199, 0.617, and 0.209). The height-based dosing algorithm of bupivacaine decreased the incidence of hypotension (p = 0.004), induced lower sensory block level and less degree of motor block (p = 3.513 × 10^-7 and 5.711 × 10^-11). The quality of analgesia, quality of muscle relaxation, and degree of intraoperative comfort were similar in both groups (p = 0.065, 0.498, and 0.483).

Conclusions

The height influences the dose of bupivacaine in spinal anesthesia; without prophylactic fluid pre-loading and vasopressors, the height-based dosing algorithm of bupivacaine is suitable, and meets the cesarean section' requirement with less maternal hypotension.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier: NCT03497364.

Maternal obesity-associated disruption of polarized lactate transporter MCT4 expression in human placenta

Maternal obesity is associated with an increased risk of adverse pregnancy outcomes including stillbirth, and their etiology is thought to be related to placental and fetal hypoxia. In this study, we sought to investigate the levels of lactate in maternal and umbilical cord blood, a well characterized biomarker for hypoxia, and expression of plasma membrane lactate transporter MCT1 and MCT4 in the placental syncytiotrophoblast (STB), which are responsible for lactate uptake and extrusion, respectively, from pregnant women with a diagnosis of obesity following a Cesarean delivery at term. With use of approaches including immunofluorescence staining, Western blot, RT-qPCR and ELISA, our results revealed that in controls the expression of MCT1 was equally observed between basal (fetal-facing, BM) and microvillous (maternal-facing, MVM) membrane of the STB, whereas MCT4 was predominantly expressed in the MVM but barely detected in the BM. However, obese patients demonstrated significant decreased MCT4 abundance in the MVM coupled with concurrent elevated expression in the BM. We also found a linear trend toward decreasing MCT4 expression ratio of MVM to BM with increasing maternal pre-pregnancy BMI. Furthermore, our data showed that the lactate ratios of fetal cord arterial to maternal blood were remarkably reduced in obese samples compared to their normal counterparts. Collectively, these results suggest that the loss of polarization of lactate transporter MCT4 expression in placental STB leading to disruption of unidirectional lactate transport from the fetal to the maternal compartment may constitute part of mechanisms linking maternal obesity and pathogenesis of stillbirth.

The association of fetal acidemia with adverse neonatal outcomes at time of scheduled cesarean delivery

BACKGROUND

Fetal acidemia at the time of a scheduled cesarean delivery is generally unexpected. In the setting of reassuring preoperative monitoring, the duration of fetal acidemia in this scenario is presumably brief. The neonatal sequelae and risks associated with brief fetal acidemia in this setting are unknown.

OBJECTIVE

We aimed to assess whether fetal acidemia at the time of a scheduled prelabor cesarean delivery is associated with adverse neonatal outcomes.

STUDY DESIGN

This was a retrospective cohort study of singleton, term, nonanomalous, liveborn neonates delivered by scheduled cesarean delivery that was performed under regional anesthesia from 2004 to 2014 at a single tertiary care center with a universal umbilical cord gas policy. Neonates born to laboring gravidas and those whose cesarean delivery was performed for nonreassuring fetal status were excluded. All included patients had reassuring preoperative fetal monitoring. The primary outcome was a composite adverse neonatal outcome that included neonatal death, encephalopathy, therapeutic hypothermia, seizures, intubation, and respiratory distress. This outcome was compared between patients with and those without fetal acidemia (umbilical artery pH <7.2). A multivariable logistic regression was used to adjust for confounders. Cases of fetal acidemia were further characterized as respiratory, metabolic, or mixed acidemia based on additional umbilical cord gas values. Secondary analyses examining the association between the type of acidemia and neonatal outcomes were also performed.

RESULTS

Of 2081 neonates delivered via scheduled cesarean delivery, 252 (12.1%) had fetal acidemia at the time of delivery. Acidemia was more common in breech neonates and in neonates born to gravidas with obesity and gestational diabetes mellitus. Compared with fetuses with normal umbilical artery pH, those with fetal acidemia were at a significantly increased risk for adverse neonatal outcome (adjusted relative risk, 2.95; 95% confidence interval, 2.03-4.12). This increased risk was similar regardless of the type of acidemia.

CONCLUSION

Even a brief period of mild acidemia is associated with adverse neonatal outcomes at the time of a scheduled cesarean delivery despite reassuring preoperative monitoring. Addressing modifiable intraoperative factors that may contribute to fetal acidemia at the time of a scheduled cesarean delivery, such as maternal hypotension and prolonged operative time, is an important priority to potentially decrease neonatal morbidity in full-term gestations.

Short-term morbidity and types of intrapartum hypoxia in the newborn with metabolic acidaemia: a retrospective cohort study

Objectives

To assess labour characteristics in relation to the occurrence of Composite Adverse neonatal Outcome (CAO) within a cohort of fetuses with metabolic acidaemia.

Design

Retrospective cohort study.

Setting

Three Italian tertiary maternity units.

Population

431 neonates born with acidaemia ≥36 weeks.

Methods

Intrapartum CTG traces were assigned to one of these four types of labour hypoxia: acute, subacute, gradually evolving and chronic hypoxia. The presence of CAO was defined by the occurrence of at least one of the following: Sarnat Score grade ≥2, seizures, hypothermia and death <7 days from birth.

Main outcome measures

To compare the type of hypoxia on the intrapartum CTG traces among the acidaemic neonates with and without CAO.

Results

The occurrence of a CAO was recorded in 15.1% of neonates. At logistic regression analysis, the duration of the hypoxia was the only parameter associated with CAO in the case of an acute or subacute pattern (odds ratio [OR] 1.3; 95% CI 1.02–1.6 and OR 1.04; 95% CI 1.0–1.1, respectively), whereas both the duration of the hypoxic insult and the time from PROM to delivery were associated with CAO in those with a gradually evolving pattern (OR 1.13; 95% CI 1.01–1.3 and OR 1.04; 95% CI 1.0–1.7, respectively). The incidence of CAO was higher in fetuses with chronic antepartum hypoxia than in those showing CTG features of intrapartum hypoxia (64.7 vs. 13.0%; P < 0.001).

Conclusions

The frequency of CAO seems related to the duration and the type of the hypoxic injury, being higher in fetuses showing CTG features of antepartum chronic hypoxia.

Tweetable abstract

This study demonstrates that in a large population of neonates with metabolic acidaemia at birth, the overall incidence of short‐term adverse outcome is around 15%. Such risk seems closely correlated to the duration and the type of hypoxic injury, being higher in fetuses admitted in labour with antepartum chronic hypoxia than those experiencing intrapartum hypoxia.

This study demonstrates that in a large population of neonates with metabolic acidaemia at birth, the overall incidence of short‐term adverse outcome is around 15%. Such risk seems closely correlated to the duration and the type of hypoxic injury, being higher in fetuses admitted in labour with antepartum chronic hypoxia than those experiencing intrapartum hypoxia.

Association of umbilical cord blood gas values with mortality and severe neurologic injury in preterm neonates <29 weeks' gestation: a national cohort study

BACKGROUND

Umbilical cord arterial and venous blood gas values reflect the acid-base balance status of a newborn at birth. Derangement in these values has been linked to poor neonatal outcomes in term and late preterm neonates; however, the utility of these values in preterm neonates of <29 weeks' gestation is unclear.

OBJECTIVE

This study aimed to determine the associations of umbilical cord arterial and venous blood gas values with neonatal mortality and severe neurologic injury in extremely preterm neonates and to identify the cutoff values associated with 2.5-fold increases or decreases in the posttest probabilities of outcomes.

STUDY DESIGN

This was a retrospective cohort study of neonates who were born at 23+0 to 28+6 weeks' gestation between January 1, 2018 and December 31, 2019, and who were admitted to neonatal units in Canada.

EXPOSURE

Various cut-offs of umbilical cord blood gas values and lactate values were studied.

MAIN OUTCOMES AND MEASURES

The main outcomes were mortality before discharge from the neonatal unit and severe neurologic injury defined as grade 3 or 4 periventricular or intraventricular hemorrhage or periventricular leukomalacia. The outcome rates were calculated for various cutoff values of umbilical cord blood gas parameters and were adjusted for birthweight, gestational age, sex, and multiple births. Likelihood ratios were calculated to derive posttest probabilities.

RESULTS

A total of 1040 and 1217 neonates had analyzable umbilical cord arterial and venous blood gas values, respectively. In the cohort, the mean (standard deviation) gestational age was 26.5 (1.5) weeks, the mean birthweight was 936 (215) g, the prevalence of mortality was 10% (105/1040), and the prevalence of severe neurologic injury was 9% (92/1016). An umbilical cord arterial pH of ≤7.1 and base excess of ≤-12 mmol/L were associated with >2.5-fold higher posttest probability of mortality, and an umbilical cord arterial or venous lactate value of <3 was associated with a 2.5-fold lower posttest probability of mortality. An umbilical cord arterial base excess of <-16 mmol/L was associated with a higher posttest probability of severe neurologic injury, whereas a lactate value of <3 was associated with a lower posttest probability.

CONCLUSION

In preterm neonates of <29 weeks' gestation, low umbilical cord arterial pH and high umbilical cord arterial base excess values were associated with a clinically important increase in the posttest probability of mortality, whereas low umbilical cord arterial or venous lactate values were associated with a decrease in the posttest probability of mortality.

Point-of-care assessment of combined umbilical arterial and venous lactate: A potential screening test for neonatal acidosis

OBJECTIVE

To examine the relationship between point-of-care (POC) measurement of combined umbilical arterial and venous (CUAV) lactate and umbilical artery (UA) lactate to determine whether POC assessment of this sample could be an alternative screening modality for neonatal acidosis and aid prediction of neonatal morbidity.

METHODS

In this cross-sectional pilot study, UA and CUAV cord blood samples were collected from live, singleton neonates delivered between June and August 2019, at a tertiary care center. UA samples were analyzed for pH and lactate using a blood gas analyzer. CUAV lactate was also assessed on a blood gas analyzer and at the POC. Linear regression was used to determine the correlation between these samples.

RESULTS

A total of 152 neonates were included. There was a statistically significant correlation between CUAV lactate concentrations and UA lactate concentrations (R²  = 0.744). Additionally, CUAV lactate concentration measured at the POC was significantly correlated with that measured on a traditional blood gas analyzer (R²  = 0.928).

CONCLUSION

POC testing of CUAV lactate is reliable and closely correlated with UA lactate concentrations, making POC testing of CUAV lactate a potential screening test for neonatal acidosis. More data are needed to establish standardization of this test relative to its predictive value in clinical neonatal outcomes.

Blood gas measures as predictors for neonatal encephalopathy severity

OBJECTIVE

To correlate arterial umbilical cord gas (aUCG) and infant blood gas with severity of neurological injury.

STUDY DESIGN

Retrospective single-site study of infants evaluated for therapeutic hypothermia. Clinical neurological examination and a validated MRI scoring system were used to assess injury severity.

RESULTS

Sixty-eight infants were included. aUCG base deficit (BD) and lactate correlated with infant blood gas counterparts (r = 0.43 and r = 0.56, respectively). aUCG and infant pH did not correlate. Infant blood gas lactate (R_ADJ² = 0.40), infant BD (R_ADJ² = 0.26), infant pH (R_ADJ² = 0.17), aUCG base deficit (R_ADJ² = 0.08), and aUCG lactate (R_ADJ² = 0.11) were associated with clinical neurological examination severity. aUCG and infant blood gas measures were not correlated with MRI score.

CONCLUSION

Metabolic measures from initial infant blood gases were most associated with the clinical neurological examination severity and can be used to evaluate hypoxic-ischemic cerebral injury risk.

Calcium and lactate in the fetal-to-neonatal transition

OBJECTIVE

To explore the relationship between calcium and lactate in arterial cord blood of healthy term neonates in response to the stress of labor.

METHODS

This was a prospective cohort study of consecutive, vaginal, term births in a community medical center (April 2029 to February 2020). Calcium and lactate were measured in cord blood gas analysis immediately after delivery.

RESULTS

In the arterial cord blood of 480 neonates, calcium levels were 1.5 (1.4; 1.5) mmol/L and lactate levels were 3.8 (2.9; 4.9) mmol/L. Calcium and lactate showed a statistically significant positive correlation (Pearson's correlation, r = 0.15, p = .001). Calcium levels had a significant positive correlation with PaCO₂ and a significant negative correlation with pH, PaO₂, HCO₃^-, and ABE levels. Multivariable analysis models confirmed that calcium levels were associated with HCO₃^-, gestational age, and birth weight, all accounting for 7% of the variability.

CONCLUSION

In healthy term vaginally delivered neonates, it was found that calcium and lactate were strongly correlated, together pointing to a neonatal response to the stress of labor and delivery. Cord blood calcium regulation may have an ancillary role in defining neonatal adaptation to extrauterine life.

Mild Neonatal Acidemia is Associated with Neonatal Morbidity at Term

OBJECTIVE

The aim of this study is to determine the association between mild acidemia (umbilical artery [UA] pH: 7.11-7.19) and neonatal morbidity in neonates at term.

STUDY DESIGN

This is a secondary analysis of a prospective cohort of women admitted for labor at ≥37 weeks of gestation within a single institution from 2010 to 2015. Universal umbilical cord blood gas assessment was performed and validated. A composite neonatal morbidity index was created including respiratory distress, mechanical ventilation, meconium aspiration syndrome, suspected or confirmed sepsis, hypoxic-ischemic encephalopathy, need for therapeutic hypothermia, seizures and death. The cohort was stratified by UA pH into normal (≥7.20), mild acidemia (7.11-7.19), acidemia (7.00-7.10), and severe acidemia (≤7.00). A subanalysis was also performed where neonates with UA pH between 7.11 and 7.19 were further stratified into two groups (7.11-7.14 and 7.15-7.19) to determine if mildly acidotic infants at the lower end of the pH range were at increased risk of morbidity. Multivariable logistic regression was used to estimate the association between UA pH and neonatal morbidity.

RESULTS

Among 6,341 participants, 614 (9.7%) had mild acidemia. These infants were more likely to experience morbidity compared with those with normal UA pH (adjusted odds ratio [aOR]: 2.14; [1.68-2.73]). Among neonates with mild acidemia, UA pH 7.11 to 7.14 was associated with increased risk of composite neonatal morbidity (aOR: 3.02; [1.89-4.82]), as well as respiratory distress and suspected or confirmed sepsis when compared with UA pH 7.15 to 7.19.

CONCLUSION

These data demonstrate that term neonates with mild acidemia at birth are at higher odds for short-term morbidity compared with neonates with normal UA pH. Furthermore, among neonates with mild acidemia, those with lower UA pH had worse neonatal outcomes than those with higher UA pH. This suggests that closer evaluation of neonates with UA pH higher than traditionally used could allow for earlier detection of morbidity and possible intervention.

KEY POINTS

· Neonates with mild acidemia (umbilical artery [UA] pH: 7.11-7.19) demonstrated an increased risk of composite morbidity compared with those with normal UA pH (≥7.20).. · Among neonates with mild acidemia, those with lower UA pH (7.11-7.14) had a greater risk of morbidity compared with those with higher UA pH (7.15-7.19), suggesting a progression of risk of morbidity as UA pH decreases.. · The majority of prior research has focused on severe acidemia (UA pH ≤ 7.00) using outcomes of severe neurologic morbidity and mortality. These data suggest that an increased risk of morbidity exists at higher pH values when more proximal and less severe outcomes are included, such as respiratory distress and neonatal sepsis..

Interventions for Intrapartum Fetal Heart Rate Abnormalities

Intrapartum fetal heart rate (FHR) decelerations may represent interrupted oxygen transfer to the fetus. In many cases, these interruptions are transient and do not result in progressive fetal acidemia with risk for asphyxia and neurological compromise. When significant FHR decelerations are present, reversible causes of reduced fetal oxygen delivery should be considered and corrective measures should be undertaken to optimize oxygenation. In this review, we describe potential intrapartum causes of reduced fetal oxygen delivery and the efficacy of common interventions for an abnormal FHR tracing.

The effect of adolescent and advanced-age pregnancies on maternal and early neonatal clinical data

BACKGROUND

This study compared early post-natal clinical data of adolescent and advanced maternal-age mothers and their infants and early post-natal clinical data of mothers 20-34 years old who delivered and their infants.

METHODS

This retrospective study included 1676 newborns who were born at or after 25 gestational weeks and 1638 puerperal women who gave birth at the Health Sciences University Bakırköy Dr. Sadi Konuk Health Practice and Research Center Gynecology and Obstetrics Clinic between January 2017 and January 2018. Maternal demographic and clinical data and neonatal demographic, anthropometric, and early delivery room clinical data of the study group patients were transcribed from clinical file records to electronic records.

RESULTS

We found that the intensive care admission/2nd- or 3rd-level intensive care referral rates of newborns of advanced-age and adolescent mothers were significantly higher than those of the control group. No significant differences were found between intensive care admission and referral rates among age groups when only healthy pregnancies were considered. Cesarean sections, abortion and smoking rates of mothers with advanced maternal age; LGA rates of newborns of women in this age group; macrosomic rates; and free-flow oxygen requirements were significantly higher than in the other age groups. In advanced-age healthy pregnancies, abortion rates were the same as those in the control group, and there was no significant difference in the LGA rate or free-flow oxygen requirement of newborns in this group. Additionally, the 1-min APGAR scores of the newborns of advanced-age mothers were significantly lower than those of the control newborns, and the pCO₂ values measured in the cord or blood gases obtained within the first hour were significantly higher. In healthy pregnancies, no significant differences in APGAR scores or pCO₂ values were found between age groups. The cord or blood gas lactate values of newborns who were born from adolescent pregnancies taken within the first hour were significantly higher than those of newborns born in other age groups; considering only healthy adolescent pregnancies, the results did not change. Newborns born from healthy adolescent pregnancies had significantly lower resuscitation needs than those born from other age groups.

CONCLUSIONS

Newborns who are born from adolescent and advanced-age pregnancies are more likely to have risky early post-natal clinical findings than are newborns who were born from mothers 20-34 years of age. The early period clinical approach and follow-up of newborns born from adolescent and advanced-age maternal pregnancies are very important for pediatric management.

Maternal Oxygen Supplementation Compared With Room Air for Intrauterine Resuscitation: A Systematic Review and Meta-analysis

IMPORTANCE

Supplemental oxygen is commonly administered to pregnant women at the time of delivery to prevent fetal hypoxia and acidemia. There is mixed evidence on the utility of this practice.

OBJECTIVE

To compare the association of peripartum maternal oxygen administration with room air on umbilical artery (UA) gas measures and neonatal outcomes.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials were searched from February 18 to April 3, 2020. Search terms included labor or obstetric delivery and oxygen therapy and fetal blood or blood gas or acid-base imbalance.

STUDY SELECTION

Studies were included if they were randomized clinical trials comparing oxygen with room air at the time of scheduled cesarean delivery or labor in patients with singleton, nonanomalous pregnancies. Studies that did not collect paired umbilical cord gas samples or did not report either UA pH or UA Pao2 results were excluded.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by 2 independent reviewers. The analysis was stratified by the presence or absence of labor at the time of randomization. Data were pooled using random-effects models.

MAIN OUTCOMES AND MEASURES

The primary outcome for this review was UA pH. Secondary outcomes included UA pH less than 7.2, UA Pao2, UA base excess, 1- and 5-minute Apgar scores, and neonatal intensive care unit admission.

RESULTS

The meta-analysis included 16 randomized clinical trials (n = 1078 oxygen group and n = 974 room air group). There was significant heterogeneity among the studies (I2 = 49.88%; P = .03). Overall, oxygen administration was associated with no significant difference in UA pH (weighted mean difference, 0.00; 95% CI, -0.01 to 0.01). Oxygen use was associated with an increase in UA Pao2 (weighted mean difference, 2.57 mm Hg; 95% CI, 0.80-4.34 mm Hg) but no significant difference in UA base excess, UA pH less than 7.2, Apgar scores, or neonatal intensive care unit admissions. Umbilical artery pH values remained similar between groups after accounting for the risk of bias, type of oxygen delivery device, and fraction of inspired oxygen. After stratifying by the presence or absence of labor, oxygen administration in women undergoing scheduled cesarean delivery was associated with increased UA Pao2 (weighted mean difference, 2.12 mm Hg; 95% CI, 0.09-4.15 mm Hg) and a reduction in the incidence of UA pH less than 7.2 (relative risk, 0.63; 95% CI, 0.43-0.90), but these changes were not noted among those in labor (Pao2: weighted mean difference, 3.60 mm Hg; 95% CI, -0.30 to 7.49 mm Hg; UA pH<7.2: relative risk, 1.34; 95% CI, 0.58-3.11).

CONCLUSIONS AND RELEVANCE

This systematic review and meta-analysis suggests that studies to date showed no association between maternal oxygen and a clinically relevant improvement in UA pH or other neonatal outcomes.

Umbilical Cord Blood Gas Parameters and Apgar Scoring in Assessment of New-Born Dogs Delivered by Cesarean Section

Simple Summary

The article presents the results of the clinical evaluation and umbilical cord blood analysis obtained from newborn pups delivered by the elective Caesarean section. In human medicine both the umbilical cord blood and Apgar score were proved to provide valuable information on neonatal status. In veterinary medicine very few reports concerning the relation between the clinical neonatal assessment (Apgar score) and umbilical cord blood parameters exist. All puppies show mild respiratory acidemia regardless the Apgar scores result. The lactates were not elevated whereas all the puppies with low Apgar sores had higher glucose and mortality rates. Only pups with low initial Apgar scores were at risk of death within first 24 h. Adaptation to the extra-uterine life is crucial and any practical improvement in neonatal diagnostics and care would be beneficial for newborn puppy survival.

Abstract

The article presents the results of the clinical evaluation (Apgar scores, AS) and umbilical cord blood gas analysis (UCBGA) obtained from clamped umbilical cords of newborn pups delivered by the elective Caesarean section. The study was planned as a controlled clinical study, the newborns were allocated into one of the groups, I—critical neonates (severe distress, AS ≤ 3), II—weak neonates (moderate distress, AS 4–6) and III—healthy neonates (no distress, AS ≥ 7). The following parameters were evaluated: pH (pH units), carbon dioxide partial pressure (pCO₂; mmHg), oxygen partial pressure (pO₂; mmHg), actual bicarbonate (cHCO₃⁻; mmol/L), total carbon dioxide (cTCO₂; mmol/L), base excess of extracellular fluid (BE(ecf); mmol/L), base excess of blood (BE(b); mmol/L), oxygen saturation (csO₂; %), lactate (Lac; mg/dL), hematocrit (Hct; %PCV), hemoglobin (cHgb; g/dL), glucose (Glu; mg/dL), ions (Na, K, Ca, Cl). The majority of puppies had low AS at birth (AS 4–6 in 38.1% and AS ≤ 3 in 57.1% of the neonates), but most of them (85.7%) improved by the 20th min. reaching AS of 7 and more. Moreover, puppies with lower AS (≤ 3) were at higher risk of death within the first 24h (20.8% did not survive). The positive correlation was found between Apgar score measured at 0 min and pH (r = 0.46, p = 0.01), and between Apgar score (at 0 min) and base excess in whole blood measured [BE(b)] r = 0.36, p = 0.03). Whereas, a negative correlation was detected between Apgar score at 0 and 5th min and glycemia (r = −0.42, p = 0.05, r = −0.34, p = 0.02 respectively. Overall, the puppies with higher glucose levels had lower Apgar scores and were at higher risk of death. Furthermore, in our study, the newborn puppies had mild acidemia with elevated pCO₂ levels and the HCO₃ at the lower range of normal limits, suggesting the mixed component in the acidemic state. Adaptation to extra-uterine life is crucial and any practical improvement in neonatal diagnostics and care would be beneficial for newborn puppy survival.

Reference Values for Umbilical Artery Lactate by Mode of Delivery and Gestational Age: A Retrospective Observational Study

INTRODUCTION

Umbilical artery cord blood provides information about the intrauterine metabolism during labor. Umbilical artery lactate is a useful parameter in predicting neonatal morbidity, but data on normal values are limited. We aimed to provide reference ranges of umbilical artery lactate values across the combination of gestational age and mode of delivery.

METHODS

A single-center retrospective observational study of liveborn infants born between 23 and 42 completed weeks gestation was conducted. Lactate, base deficit (BD), and pH from arterial cord blood were assessed between June 2018 and November 2020 and compared across gestational ages and modes of delivery.

RESULTS

Overall, there were 3,353 infants with evaluable data. Lactate values at the 50th, 90th, and 97th percentile were 3.4, 7.0, and 9.0 mmol/L. Lactate was inversely correlated with pH (r = -0.77, p < 0.001) and positively correlated with BD (r = 0.63, p < 0.001). Lactate values changed significantly across gestational age (Kruskal-Wallis test, p < 0.001) which was attributable to an increase in lactate at 39-41 weeks gestational age. Also, lactate values were different across modes of delivery (Kruskal-Wallis test, p < 0.001) with lowest values in elective CS and highest values in vaginal instrumental deliveries. Comprehensive reference ranges across modes of delivery and gestational ages could be established.

DISCUSSION

Mode of delivery and gestational age contribute to lactate levels with highest values occurring in vaginal instrumental deliveries and between 39 and 41 weeks gestational age. Based on these observations, we provide detailed reference ranges for clinical use.

Umbilical cord lactate compared with pH as predictors of intrapartum asphyxia

Despite advances in fetal monitoring during labor, one of the most critical causes of neonatal death and neurologic injuries remains intrapartum asphyxia. Umbilical cord gases can be used to detect acidosis and fetal distress. We conducted a retrospective, multicenter study to evaluate umbilical cord blood pH and lactate as a mean of evaluating the degree of intrapartum hypoxia and also to establish which of the two is more reliable in predicting morbidity in term neonates. The present study utilized a total of 124 cases that met the criteria for intrapartum asphyxia and 150 normal term newborns that were randomly selected as case control. Both umbilical cord lactate and pH proved to be accurate predictors of neonatal morbidity caused by intrapartum hypoxia. Lactate proved to be superior to pH in predicting adverse neonatal outcome. The greatest sensibility and specificity in predicting intrapartum asphyxia were achieved in our study by using a cutoff value of 3.75 mmol/l for lactate and 7.24 for pH.

The effects of time and temperature on umbilical cord gas analysis

OBJECTIVE

Our objective was to evaluate the effects of time and temperature on umbilical-cord blood analysis.

METHODS

This prospective study included the term spontaneous vaginal deliveries. One venous and seven arterial samples were drawn from each umbilical cord within 5 min from delivery. Three samples were immediately refrigerated (3 °C), while all other samples were stored at room temperature (23-26 °C). Samples were analyzed in pairs (refrigerated and room-temperature samples) at 0, 20, 40, and 60 min after delivery for pH and lactate levels. Repeated-measures analysis using a generalized linear model was used to compare the change in pH and lactate values over time.

RESULTS

518 samples from 74 women were analyzed. The mean gestational age was 39.1 ± 1.1 weeks. All neonates had an Apgar score of ≥9 in the 1st and 5th minutes. Mean arterial pH and lactate levels at delivery (time 0) were 7.32 ± 0.07 and 4.00 ± 1.36 mmol/L, respectively. Over time, a statistically significant decrease in pH and a reciprocal increase in lactate levels were observed. The mean change in arterial pH following 60 min was 0.021 ± 0.028 (room-temperature) and 0.016 ± 0.023 (refrigerated); p < 0.001. Compared to pH, a greater change was demonstrated in lactate levels over time; the mean change in lactate following 60 min was -0.896 ± 0.535 (room temperature) and -0.512 ± 0.450 mmol/L (refrigerated). Temperature significantly altered both pH and lactate levels, but lactate levels were altered at earlier time points.

CONCLUSION

Both time and temperature have significant effects on cord blood analysis. Yet, these changes are minor and may not have any clinical significance unless in extreme cases in which medicolegal aspects emerge.

Predicting long-term neurodevelopmental outcomes in very preterm neonates by umbilical cord gas parameters

BACKGROUND

The predictive value of acidemia at birth on long-term neurodevelopmental outcomes remains poorly understood, especially in preterm neonates.

OBJECTIVE

This study aimed to assess the relationship between the umbilical artery acid-base status and major neurodevelopmental disability at an age of between 5 and 8 years among children born very prematurely.

STUDY DESIGN

We performed a secondary analysis of the data from a follow-up study of a prospective cohort of 457 children aged between 23 weeks and 31 weeks and 6 days from 1996 to 2001. Arterial cord gas parameters that were <10th percentile in the original cohort of 457 neonates (ie, pH of <7.1, base deficit of <-8.6 mEq/L, and a partial pressure of CO₂ of >77 mm Hg) were considered abnormal. Sensitivity analyses considered alternative definitions for abnormal cord gases including a pH of <7.0 or base deficit of <-12 mEq/L. The primary outcome was a composite of major neurodevelopmental disability, including an intelligence quotient score of <70, cerebral palsy, blindness, deafness, abnormal balance, impaired cognition, dystonia, and seizure disorder. A logistic regression analysis was used to adjust for race and caregiver intelligence quotient score and, in an additional analysis, for gestational age.

RESULTS

A total of 259 of 261 maternal-infant dyads were evaluated at a mean child age of 6.8 years, with complete umbilical cord gas data for 228 of those. Infants with an abnormal pH and a base deficit (defined above) were over 4-fold more likely to have the composite disability and an intelligence quotient score of <70. These increased odds persisted after adjusting for age and caregiver intelligence quotient score, but when considering gestational age as well, none of the umbilical cord gas parameters significantly predicted the presence of the composite disability or an intelligence quotient score of <70. However, when using the stricter umbilical cord gas criteria (ie, pH of <7.0 and a base deficit of <-12 mEq/L), a base deficit of <-12 mEq/L was independently associated with both neurodevelopmental disability and an intelligence quotient score of <70.

CONCLUSION

When defined more strictly, abnormal umbilical cord gases, specifically a base deficit of <-12 mEq/L, are associated with an increased risk for major long-term neurodevelopmental disability and an intelligence quotient score of <70 in children born very prematurely.

Diabetes Leads to Alterations in Normal Metabolic Transitions of Pregnancy as Revealed by Time-Course Metabolomics

Women with diabetes during pregnancy are at increased risk of poor maternal and neonatal outcomes. Despite this, the effects of pre-gestational (PGDM) or gestational diabetes (GDM) on metabolism during pregnancy are not well understood. In this study, we utilized metabolomics to identify serum metabolic changes in women with and without diabetes during pregnancy and the cord blood at birth. We observed elevations in tricarboxylic acid (TCA) cycle intermediates, carbohydrates, ketones, and lipids, and a decrease in amino acids across gestation in all individuals. In early gestation, PGDM had elevations in branched-chain amino acids and sugars compared to controls, whereas GDM had increased lipids and decreased amino acids during pregnancy. In both GDM and PGDM, carbohydrate and amino acid pathways were altered, but in PGDM, hemoglobin A1c and isoleucine were significantly increased compared to GDM. Cord blood from GDM and PGDM newborns had similar increases in carbohydrates and choline metabolism compared to controls, and these alterations were not maternal in origin. Our results revealed that PGDM and GDM have distinct metabolic changes during pregnancy. A better understanding of diabetic metabolism during pregnancy can assist in improved management and development of therapeutics and help mitigate poor outcomes in both the mother and newborn.

Evolution of Gut Microbiome and Metabolome in Suspected Necrotizing Enterocolitis: A Case-Control Study

Background: Necrotizing enterocolitis (NEC) is a devastating condition in preterm infants due to multiple factors, including gut microbiota dysbiosis. NEC development is poorly understood, due to the focus on severe NEC (NEC-2/3). Methods: We studied the gut microbiota, microbiome and metabolome of children with suspected NEC (NEC-1). Results: NEC-1 gut microbiota had a higher abundance of the Streptococcus (second 10-days of life) and Staphylococcus (third 10-days of life) species. NEC-1 children showed a microbiome evolution in the third 10-days of life being the most divergent, and were associated with a different metabolomic signature than in healthy children. The NEC-1 microbiome had increased glycosaminoglycan degradation and lysosome activity by the first 10-days of life, and was more sensitive to childbirth, low birth weight and gestational age, than healthy microbiome. NEC-1 fecal metabolome was more divergent by the second month of life. Conclusions: NEC-1 gut microbiota and microbiome modifications appear more distinguishable by the third 10-days of life, compared to healthy children. These data identify a precise window of time (i.e., the third 10-days of life) and provide microbial targets to fight/blunt NEC-1 progression.

Umbilical cord arterial and venous gases, ionogram, and glucose level for predicting neonatal morbidity at term

OBJECTIVE

To determine which parameter of umbilical arterial cord gas analysis, pH, base deficit, lactate concentration, ionogram values, or glucose level index is the best predictor of neonatal morbidity at term.

DESIGN

We conducted a 15-month retrospective cohort study that included all nonanomalous, singleton, term births at a single center. The predictive ability of lactate concentration, base deficit, pH, ionogram values, and glucose level were compared using receiver-operating characteristic curves for global and neurological composite morbidity. Optimal cutoff values for lactate concentration, base deficit, and pH were estimated based on their maximum area under the curve.

RESULTS

We included 5161 newborns: 52 (1.01 %) had global composite morbidity, and 17 had (0.33 %) neurological composite morbidity. Blood levels of potassium, calcium, natremia, glucose level, and HCO₃^- did not differ significantly between groups. pH, partial pressure of CO₂, partial pressure of O₂, base deficit, and lactate levels differed significantly between neonates in the groups with and without global composite morbidity. Nearly similar results were found for neurological composite morbidity. The predictive ability did not differ between arterial pH and arterial lactate concentration (P = .25) and base deficit (P = .79). Optimal cutoff values to predict global composite morbidity were arterial pH 7.144, venous pH 7.236, and arterial lactate concentration 6.5 mmol/L.

CONCLUSIONS

Acid-base status analysis remains the best objective indicator for predicting neonatal morbidity and can be estimated using pH, lactate, or base deficit. Ionogram cord blood composition and glucose level do not appear to be useful for this purpose.

Gestational age reference ranges for umbilical cord blood lactate: An external validation study of post-date pregnancies

A previous study published in 2008 by Wiberg et al demonstrated increasing umbilical cord blood lactate at delivery by gestational age in vigorous offspring (n = 10 169, gestational age 24-43 weeks). Based on these results the authors concluded that gestational age-independent umbilical cord lactate cut-off could give false-negative or false-positive diagnosis of lacticemia. To our knowledge, these findings have not been incorporated into clinical interpretations in delivery units. To perform an external validity study for the findings by Wiberg et al, we analyzed umbilical cord blood lactate levels according to gestational age in a post-date delivery study population at our large, tertiary obstetric unit. The parallel finding of our study to that of Wiberg et al highlights the importance of using available gestational age dependent reference ranges (eg as presented in Wiberg's publication), when interpreting umbilical cord blood lactate levels for fetal wellbeing.

Marked variability in intrapartum electronic fetal heart rate patterns: association with neonatal morbidity and abnormal arterial cord gas

OBJECTIVE

Investigate marked variability in fetal heart rate (FHR) patterns before delivery and its association with neonatal morbidity and abnormal arterial cord gases.

STUDY DESIGN

Prospective cohort of laboring patients at term. Composite neonatal morbidity (respiratory distress, mechanical ventilation, suspected sepsis, meconium aspiration syndrome, therapeutic hypothermia, hypoxic-ischemic encephalopathy, seizure, and death) and abnormal arterial cord gases (pH < 7.10, lactate ≥ 4 mmol/L, base deficit < -12 mEq/L) were assessed with multivariable logistic regression.

RESULT

Three hundred and ninety (4.5%) neonates had marked variability in FHR patterns before delivery. There was no difference in composite neonatal morbidity (aRR 1.22; 95% CI 0.91-1.63), though neonates with marked variability in FHR patterns were more likely to have a respiratory distress (aRR 1.85; 95% CI 1.25-2.70). There was an increased risk of composite abnormal arterial cord gases (aRR 1.66; 95% CI 1.47-1.88).

CONCLUSION

Marked variability in FHR patterns was not associated with composite neonatal morbidity but was associated with abnormal arterial cord gases.

The prognostic value of the level of lactate in umbilical cord blood in predicting complications of neonates with meconium aspiration syndrome

BACKGROUND

In spite of significant advances in therapeutic, diagnostic and even medical modalities, meconium management continues to be a concern for management. It has been recently assumed that trace of lactate in both serum and urine can be a sign of the asphyxia in neonates. However, no study has been done on the prognostic value of increasing lactate concentration in umbilical cord blood for predicting the outcomes of meconium aspiration syndrome (MAS), which was our aim in this study.

METHODS

Thin cross-sectional study was performed on 150 neonates suffering meconium aspiration syndrome who were admitted to Akbar Abadi hospital in Tehran between 2016 and 2018. Samples of umbilical cord blood were extracted from neonates and sent to the reference laboratory to measure lactate level as well as arterial blood gas analysis. The neonatal characteristics as well as postdelivery complications were also collected by reviewing the hospital recorded files.

RESULTS

Thick meconium stained amniotic fluid (TKMSF) was found in 40.0% and thin meconium stained amniotic fluid (TNMSF) in 60.0%. The mean level of lactate was significantly higher in those neonates with morbidities including pulmonary hemorrhage, persistent pulmonary hypertension of the neonate (PPHN), intraventricular hemorrhage (IVH), and respiratory failure requiring ventilation support. According to the ROC curve analysis, increasing lactate in umbilical cord blood could predict occurrence of pulmonary hemorrhage (AUC = 0.885), PPHN (AUC = 0.832), IVH (AUC = 0.898), and requiring ventilation (AUC = 0.833). Comparing the two groups with TKMSF and TNMSF showed higher gestational age, lower Apgar score, lower BE, higher PCO₂, lower PO₂, lower PH as well as higher serum lactate. In this regard and using the ROC curve analysis (Table 4), increased lactate could effectively discriminate TKMSF from TNMSF (AUC = 0.998) with the best cut-off value of 4.10.

CONCLUSION

The increase in lactate in the umbilical cord blood (>4.1 mmol/L with high sensitivity and specificity) can distinguish between thick meconium and thin meconium forms in amniotic acid and thus can determine the severity of MAS. Also, increasing serum lactate levels is an accurate indicator for predicting complications such as pulmonary hemorrhage, PPHN, IVH, and need for ventilation in newborns with this syndrome. This diagnostic accuracy is even beyond the usual markers for arterial gas analysis, such as PH, PCO₂, PO₂ and BE.

Height-based dosing algorithm of bupivacaine in spinal anaesthesia for decreasing maternal hypotension in caesarean section without prophylactic fluid preloading and vasopressors: study protocol for a randomised controlled non-inferiority trial

INTRODUCTION

Effectively preventing or treating spinal-induced maternal hypotension is considered to be the Holy Grail of obstetric anaesthesia. Prophylactic fluid preloading and vasopressors decrease hypotension but may aggravate heart load, induce fetal acidosis or maternal bradycardia. Using low-dose local anaesthetic decreases hypotension but may cause insufficient anaesthesia. Whether there is a height-based dosing algorithm of local anaesthetic in spinal anaesthesia for caesarean section that can provide sufficient anaesthesia with less hypotension without prophylactic fluid preloading and vasopressors is unclear. This study was designed to investigate a height-based dosing algorithm of bupivacaine in spinal anaesthesia for caesarean section.

METHODS AND ANALYSIS

This single-centre, double-blinded, prospective, non-inferiority, randomised controlled trial will include 264 parturients (between 18 and 45 years of age) who are scheduled for caesarean section. All participants will not receive prophylactic fluid preloading. The participants will be randomly divided into two groups: the test group or conventional group. For parturients in the test group, 0.5% isobaric bupivacaine (1.15-1.70 mL) will be injected into the subarachnoid space without prophylactic vasopressors. The bupivacaine dose depends on the height of subjects. For parturients in the conventional group, 0.5% bupivacaine (1.8 mL) will be injected into the subarachnoid space along with prophylactic vasopressors. The primary outcome is the incidence of maternal hypotension. The secondary outcomes include the failure rate of spinal anaesthesia, level of sensory block, degree of motor block, other complications in parturients, time of operation, neonatal outcome and quality of anaesthesia.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee of Shenzhen People's Hospital of Jinan University (Permit No. SZY-00251, chairperson Xiaofang Yu) on 8 February 2018The study results will be disseminated through peer-reviewed journals, professional societies and meetings.

TRIAL REGISTRATION NUMBER

NCT03497364; Pre-results.

Elevated umbilical cord arterial lactate at birth and electronic fetal monitoring characteristics on admission and in the active phase

OBJECTIVE

To investigate the association between elevated umbilical arterial lactate at birth and electronic fetal monitoring (EFM) characteristics at admission and in the beginning of the active phase of labor.

STUDY DESIGN

Nested case-control study within a prospective cohort of laboring patients at term who achieved active labor. Neonates with umbilical arterial lactate ≥ 4 mmol/L (cases, n = 119), were matched 1:1 to controls with lactate < 4 mmol/L. EFM patterns were compared with multivariable logistic regression.

RESULT

There were no differences in EFM parameters in the first 60 minutes after admission. At the beginning of active labor, 13.5% of cases and 26.1% of controls had always category I tracings, adjusted odds ratio 0.48, 95% confidence interval 0.24-0.94). Cases were less likely to have an always category I tracing from admission into the active phase.

CONCLUSION

Elevated umbilical arterial lactate at birth is associated with distinct EFM patterns early in the labor course.

Effect of Oxygen vs Room Air on Intrauterine Fetal Resuscitation: A Randomized Noninferiority Clinical Trial

IMPORTANCE

Two-thirds of women in labor receive supplemental oxygen to reverse perceived fetal hypoxemia and prevent acidemia. Oxygen is routinely administered for category II fetal heart tracings, a class of fetal tracing used to designate intermediate risk for acidemia. This liberal use of oxygen may not be beneficial, particularly because neonatal hyperoxygenation is harmful.

OBJECTIVE

To test the hypothesis that room air is noninferior to oxygen in improving fetal metabolic status among patients with category II fetal heart tracings.

DESIGN, SETTING, AND PARTICIPANTS

This was a randomized, unblinded noninferiority clinical trial conducted between June 2016 and July 2017 in the labor and delivery ward of a single tertiary care center. Women with singleton pregnancies at 37 weeks' gestational age or more who were admitted for delivery were eligible. Of those who met inclusion criteria, the patients who developed category II tracings in labor that necessitated intrauterine resuscitation were randomized in a 1:1 ratio to room air or oxygen. Analyses were intention-to-treat.

INTERVENTIONS

The oxygen group received 10 L of oxygen per minute by nonrebreather facemask until delivery. The room air group was exposed to room air only without a facemask.

MAIN OUTCOMES AND MEASURES

The primary outcome was umbilical artery lactate, a marker of metabolic acidosis and neonatal morbidity. Noninferiority was defined as a mean difference between groups of less than 9.0 mg/dL (1.0 mmol/L). Secondary outcomes were other umbilical artery gases, cesarean delivery for nonreassuring fetal status, and operative vaginal delivery.

RESULTS

Of the 705 patients who met inclusion criteria, 277 (39.3%) were enrolled on admission. During labor, 114 patients (41.2% of the enrolled patients) developed category II tracings and were randomized to room air (57 patients; 50.0% of the randomized patients) or oxygen (57 patients; 50.0% of the randomized patients). A total of 99 patients (86.8% of the randomized patients) with paired cord gases were included in the modified intention-to-treat analysis. The 99 patients included 76 African American women (77%); mean (SD) age was 27.3 (6.3) years in the oxygen group and 27.8 (5.3) years in the room air group. There was no difference in umbilical artery lactate between the group on oxygen and the group on room air (mean, 30.6 mg/dL [95% CI, 27.0 to 34.2 mg/dL] vs 31.5 mg/dL [95% CI, 27.9 to 36.0 mg/dL]); P = .69). The mean difference in lactate was 0.9 mg/dL (95% CI, -4.5 to 6.3 mg/dL), which was within the noninferiority margin. There was no difference in other umbilical artery gas components or mode of delivery between groups.

CONCLUSIONS AND RELEVANCE

Among patients with category II fetal heart tracings, intrauterine resuscitation with room air is noninferior to oxygen in improving umbilical artery lactate. The results of this trial challenge the efficacy of a ubiquitous obstetric practice and suggest that room air may be an acceptable alternative.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02741284.

The comparison of umbilical cord arterial blood lactate and pH values for predicting short-term neonatal outcomes

OBJECTIVE

Current clinical practice of assessing neonatal condition is based on evaluation of umbilical cord arterial blood pH value rather than lactate. However, evidence shows that lactate is direct and more predictive measurement than pH or at least of equal importance. This study is to assess and compare umbilical cord arterial lactate and pH values for predicting short-term neonatal outcomes.

MATERIALS AND METHODS

A retrospective cohort study was conducted at the tertiary level hospital, were arterial umbilical cord blood sampling was collected according to the standard procedures. Neonatal morbidity was registered if at least one of the following conditions was noted: Apgar score at 1 min after delivery was 6 or lower, resuscitation performed, including assisted ventilation and requirement of admission to neonatal intensive care unit. Mothers-newborns pairs were allocated into two groups: newborns exposed to perinatal hypoxia (group 1) and observed as healthy newborns (group 2). Receiver operating characteristics curves (ROC) were generated to assess the predictive ability of pH and lactate for the short-term neonatal outcomes.

RESULTS

901 neonates born at ≥37 weeks of gestation were included. Newborns exposed to perinatal hypoxia (group 1) encompassed 39 (4.3%) patients, and observed as healthy (group 2) - 862 (95.7%). Arterial umbilical cord blood pH in group 1 was 7.160 ± 0.126 as compared to 7.314 ± 0.083 in group 2; p < 0.001. Mean arterial lactate was significantly higher in group 1 than group 2 (6.423 ± 2.335 as compared to 3.600 ± 1.833; p < 0.001). The difference between areas under ROC curves representing pH and lactate was not significant (0.848 and 0.831 respectively; p = 0.6132).

CONCLUSION

Umbilical cord arterial lactate and pH predicted short-term neonatal outcomes with similar efficacies.

Assessment of lactate production as a response to sustained intrapartum hypoxia in large-for-gestational-age newborns

INTRODUCTION

Lactate concentration in umbilical cord blood is an important measure of intrapartum anaerobic metabolism. The aim of the study was to compare lactate production of large-for-gestational-age (LGA) fetuses against appropriate-for-gestational-age (AGA) fetuses during hypoxia, in diabetic and non-diabetic mothers.

MATERIAL AND METHODS

A total of 17 358 validated paired arterial and venous umbilical cord blood samples taken at birth with a full panel of pH, glucose, and lactate were analyzed relative to LGA (n = 2789) and AGA (n = 14 569). Umbilical cord blood acidemia (pH < mean minus 2 SD) was identified in 518 cases.

RESULTS

Diabetes, but not acidemia, was more common among LGA (5.4%) than AGA cases (2.9%) (respectively P < .0001 and P < .69). At normal pH, glucose was lower in non-diabetes LGA cases, but not in diabetes LGA compared with corresponding AGA cases (respectively P < .0001 and P < .067). Glucose levels were higher in all groups during acidemia (P ≤ .0005), with lower values in non-diabetes LGA but not in diabetes LGA compared with corresponding AGA cases (respectively P = .005 and P < .58). At normal pH, lactate was lower in non-diabetes LGA but not in diabetes LGA compared with corresponding AGA cases (respectively P < .0001 and P < .98); during acidemia, lactate levels were higher in all groups (P < .0001), resulting in no significant difference between LGA and AGA in diabetes as well as in non-diabetes cases (respectively P = .29 and P < .084).

CONCLUSIONS

Considering cord acidemia a proxy for intrapartum hypoxia, LGA fetuses showed no impaired ability to produce lactate during hypoxia. Maternal diabetes did not hamper the ability of LGA fetuses to produce lactate during hypoxia.

Determination of reference intervals for umbilical cord arterial and venous blood gas analysis of healthy Thoroughbred foals

Although umbilical cord blood gas analysis is considered the best way to assess in utero oxygenation in human neonates, there is limited evaluation of this method in equine neonatology. Our objectives were to assess the practicality of obtaining umbilical cord blood gas samples in the field and to determine umbilical cord arterial and venous blood gas reference intervals (RI) for healthy, newborn foals. Thoroughbred foals >320 days gestation from healthy mares with uneventful pregnancies at one stud farm were evaluated. All parturitions were observed, with paired umbilical arterial and venous whole-blood samples obtained immediately following parturition for blood gas and lactate concentrations measured in duplicate. Apgar scores were assigned immediately and 10 min after birth, with all foals subsequently examined on days 1-28 to monitor for development of perinatal asphyxia syndrome. Foals were excluded from analysis based on abnormalities of stage 2 labour, Apgar scores and gross and histological placental assessment. Data was analysed using a Student's t-test, Pearson's correlation and the Robust method with P ≤ 0.05 significant. Umbilical cord samples were simple to obtain with minimal disruption to the foaling environment. Of the n = 34 foals assessed, n = 7 were excluded based on premature placental separation deliveries. The mean time for stage 2 labour and blood gas analysis after parturition was 17.3 ± 5.1 min and 5.0 ± 2.3 min, respectively. RI were identified for umbilical arterial and venous pH (7.19-7.42 vs. 7.34-7.44), PO₂ (15.5-48.39 mmHg vs. 16.6-52.7 mmHg), PCO₂ (49.5-82.29 mmHg vs. 45.4-63.1 mmHg), SO₂ (9.19-76.89% vs. 39.9-84.88%), bicarbonate (27.3-38.7 mmol/l vs. 27.7-37.8 mmol/l), base excess (0.36-12.9 mmol/l vs. 1.97-13.1 mmol/l), TCO₂ (28.99-40.3 mmHg vs. 29.0-39.5 mmHg) and lactate (1.4-7.3 mmol/l vs. 1.3-4.9 mmol/l). Umbilical arterial samples had lower pH (P < 0.0001), PO₂ (P = 0.002) and SO₂ (P < 0.0001) and higher PCO₂ (P < 0.0001) and lactate (P < 0.0001) than venous samples. The initial Apgar score was positively correlated to umbilical arterial SO₂ (r = 0.4, P = 0.05) and negatively with umbilical arterial TCO₂ (r = -0.6, P = 0.004). Overall, umbilical cord sampling was simple and minimally disruptive, with RI obtained for blood gas measurements. RI for umbilical blood gas measurements from a larger population of healthy and unhealthy foals is required to evaluate the accuracy of this method for assessing in utero oxygenation.