Cord Arterial pH Research Articles

The effect of waterbirth on neonatal mortality and morbidity: a systematic review and meta-analysis.

Women have been giving birth in water in many centers across the globe; however, the practice remains controversial. Qualitative studies highlight the benefits that waterbirth confers on the laboring woman, though due to the nature of the intervention, it is not surprising that there are few randomized controlled trials available to inform practice. Much of the criticism directed at waterbirth focuses on the potential impact on the neonate. The objective of this review was to systematically synthesize the best available evidence regarding the effect of waterbirth, compared to landbirth, on the mortality and morbidity of neonates born to low risk women. This review considered studies that included low risk, well, pregnant women who labor and birth spontaneously, at term (37-42 weeks), with a single baby in a cephalic presentation. Low risk pregnancies are defined as pregnancies with an absence of co-morbidity or obstetric complication, such as maternal diabetes, previous cesarean section, high blood pressure or other illness. Women may be experiencing their first or subsequent pregnancy. The fetus must also be well and without any co-morbidity or complication.The intervention of interest is waterbirth. The comparator is landbirth. Women and their babies must be cared for by qualified maternity healthcare providers throughout their labor and birth. The birth setting must be clearly described but can include home, hospital or birth center, either freestanding or attached to a hospital.This review considered randomized controlled trials, quasi-experimental studies and observational prospective and retrospective cohort studies. A multi-step search strategy was utilized to find published and unpublished studies, in English between January 1999 and June 2014. The first author assessed the quality of all eligible studies. The three secondary authors independently assessed six studies each, followed by group discussion using the appropriate Joanna Briggs Institute appraisal checklist. Data were extracted using a standardized extraction tool from Joanna Briggs Institute. Quantitative studies were pooled, where possible, for meta-analysis using software provided by Cochrane. Effect sizes were expressed as odds ratio or relative risk, according to study design, and the 95% confidence intervals were calculated. Heterogeneity was assessed statistically using the standard Chi-square test. The meta-analyses of 12 studies showed that for the majority of outcomes measured in this review there is little difference between waterbirth and landbirth groups. Meta-analysis was not conducted for mortality within 24 days of birth. Heterogeneity was significant between studies for APGAR (Appearance, Pulse, Grimace, Activity, and Respiration). scores ≤7 at one minute and admission to Special Care nursery. Sensitivity analysis for case control studies describing infection found results that were not statistically significant (OR 0.74, 95% CI 0.05-11.06). Results of meta-analysis were also not significant for studies describing resuscitation with oxygen (OR 1.12, 95% CI 0.14-8.79) and Respiratory Distress Syndrome (OR 0.81, 95% CI 0.44-1.49). Results comparing APGAR scores ≤7 at five minutes for waterbirth and landbirth groups results for included RCTs demonstrated results that were not statistically significant (OR 6.4, 95% CI 0.63-64.71). However, results for included cohort studies describing APGAR scores ≤7 at 5 minutes indicate neonates are less likely to have scores ≤7 in the waterbirth group (OR 0.32, 95% 0.15-0.68). Data were not statistically significant for meta-analysis describing admission to NICU (OR 0.51, 95% CI 0.13-1.96) between water and landbirth groups. The differences in arterial (MD 0.02, 95% CI 0.01-0.02) and venous (MD 0.03, 95% CI 0.03-0.03) cord pH, while statistically significant, were clinically negligible. Analyses of data reporting on a variety of neonatal clinical outcomes comparing land with waterbirth do not suggest that outcomes are worse for babies born following waterbirth. Meta-analysis of results for five-minute APGAR scores ≤7 should be treated with caution due to the different direction of results for meta-analysis of data from randomized controlled trials and cohort studies. Data measuring cord pH (an objective measure of neonatal wellbeing) were robust and showed no difference between groups. Overall this review was limited by heterogeneity between studies and meta-analysis could not be conducted on a number of outcomes. Waterbirth does not appear to be associated with adverse outcomes for the neonate in a population of low risk women. There is no evidence to suggest that the practice of waterbirth in a low risk population is harmful to the neonate. There is a paucity of high level evidence to guide practice in the area of waterbirth. It is unlikely that randomized controlled trials on waterbirth will be acceptable to childbearing women or maternity caregivers. Observational studies are a more appropriate choice for researchers in this field as they offer a more practical and ethical approach.

The impact of intrauterine infection on fetal brain damage assessed by S100B protein concentrations in umbilical cord arteries

Objective: To assess the impact of intrauterine infection on fetal brain damage by measuring S100B protein concentration in umbilical cord arteries. Methods: In the intrauterine infection cases determined by pathology of 25 deliveries (Group I) and non-infection cases of 35 deliveries as control (Group C), we compared gestational age at delivery, birth weight, fetal heart rate monitoring during labor, Apgar score, umbilical cord artery pH and S100B protein concentrations in umbilical arteries measured by two-site immunoradiometric assay kit. Results: (1) There was no significant correlation between pH and concentration of S100B protein. (2) Gestational age at delivery was found to be earlier in Group I, resulting in lower birth weights, when compared with Group C. (3) There was no significant difference between two groups concerning Apgar scores, pH. (4) S100B protein concentrations in Group I was significantly higher than those of Group C (3.9 7 ± 0.66 versus 1.8 9 ± 0.56 μg/L, p < 0.05). (5) The concentration of S100B protein in severe chorioamnionitis (CAM) cases were significantly higher than those of mild CAM and control cases. Conclusion: Higher concentration of S100B protein in Group I suggests that intrauterine infection itself has a serious risk factor on fetal brain damage.

Umbilical Cord Blood pH in Intrapartum Hypoxia.

To determine the association of cord arterial blood pH with neonatal outcome in cases of intrapartum fetal hypoxia. Descriptive analytical study. Gynaecology Unit-II, Civil Hospital, Karachi, from September 2011 to November 2012. All singleton cephalic fetuses at term gestation were included in the study. Those with any anomaly, malpresentation, medical disorders, maternal age < 18 years, multiple gestation and ruptured membranes were excluded. Patients with abnormal cardiotocography and/or meconium stained liquor were enrolled as index case and immediate next delivery with no such signs as a control. Demographic characteristics, pH level < or > 7.25, neonatal outcome measures (healthy, NICU admission or neonatal death), color of liquor and mode of delivery recorded on predesigned proforma. Statistical analysis performed by SPSS 16 by using independent-t test or chi-square test and ANOVA test as needed. A total of 204 newborns were evaluated. The mean pH level was found to be significantly different (p=0.007) in two groups. The pH value 7.25 had significant association (p < 0.001) with the neonatal outcome. However, the association of neonatal outcome with severity of acidemia was not found to be significant. Grading of Meconium Stained Liquor (MSL) also did not relate positively with pH levels as 85.7% of grade I, 68.9% of grade II and 59.4% of grade III MSLhad pH > 7.25. Majority (63.6%) cases needed caesarean section as compared to 31.4% controls. There is a significant association of cord arterial blood pH at birth with neonatal outcome at pH < or > 7.25; but below the level of pH 7.25 it is still inconclusive.

Fractal Analysis and Hurst Parameter for Intrapartum Fetal Heart Rate Variability Analysis: A Versatile Alternative to Frequency Bands and LF/HF Ratio.

BackgroundThe fetal heart rate (FHR) is commonly monitored during labor to detect early fetal acidosis. FHR variability is traditionally investigated using Fourier transform, often with adult predefined frequency band powers and the corresponding LF/HF ratio. However, fetal conditions differ from adults and modify spectrum repartition along frequencies.AimsThis study questions the arbitrariness definition and relevance of the frequency band splitting procedure, and thus of the calculation of the underlying LF/HF ratio, as efficient tools for characterizing intrapartum FHR variability.Study DesignThe last 30 minutes before delivery of the intrapartum FHR were analyzed.SubjectsCase-control study. A total of 45 singletons divided into two groups based on umbilical cord arterial pH: the Index group with pH ≤ 7.05 (n = 15) and Control group with pH > 7.05 (n = 30).Outcome MeasuresFrequency band-based LF/HF ratio and Hurst parameter.ResultsThis study shows that the intrapartum FHR is characterized by fractal temporal dynamics and promotes the Hurst parameter as a potential marker of fetal acidosis. This parameter preserves the intuition of a power frequency balance, while avoiding the frequency band splitting procedure and thus the arbitrary choice of a frequency separating bands. The study also shows that extending the frequency range covered by the adult-based bands to higher and lower frequencies permits the Hurst parameter to achieve better performance for identifying fetal acidosis.ConclusionsThe Hurst parameter provides a robust and versatile tool for quantifying FHR variability, yields better acidosis detection performance compared to the LF/HF ratio, and avoids arbitrariness in spectral band splitting and definitions.

Management of breech presentation at term: a retrospective cohort study of 10 years of experience.

To evaluate the impact of management of childbirth (external cephalic version (ECV) plus planned vaginal delivery (PVD)) of breech presentation at term (⩾37 weeks of gestation). This retrospective cohort study was based on data collected of singleton breech presentations at term in the Obstetrics and Gynaecology Service, Cruces University Hospital (Biscay, Spain), from January 2003 to December 2012. We attended 2377 singleton breech pregnancies at term. We attended 1684 singleton breech term deliveries, attempting vaginal delivery after selection in 52.9% of cases and were successful in 57.5% of attempts. A total of 1360 ECV were attempted, with a success rate of 50.3% of those attempted. The use of ECV has decreased the rate of breech presentation at delivery by 39.0%, the rate of breech presentation as a caesarean section (CS) indication by 47.1% (CS due to breech presentation/total of CS) and the rate of CS for breech presentation out of the total of deliveries by 39.1% (CS due to breech presentation/total of deliveries). Early postnatal parameters (5-min Apgar score, umbilical cord arterial pH and acid-base analysis) were significantly lower following PVD compared with planned CS for breech presentation. However, we did not find any differences in the rates of admissions to the neonatal unit or neonatal mortality. Management of breech presentation with a protocol that includes ECV, careful selection criteria and active management of vaginal delivery achieve a great decrease in the rate of CS for breech presentation.

Umbilical cord blood concentrations of ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) in neonates developing hypoxic-ischemic encephalopathy

Objective: To compare ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) concentrations in umbilical cord blood of neonates who develop Sarnat stage II–III hypoxic-ischemic encephalopathy (HIE) to healthy controls, and to relate the concentrations to the severity of neurology and long-time outcomes.Material and methods: Cord sera of 15 neonates with HIE II–III and 31 matched controls were analyzed for UCH-L1 and GFAP. Comparisons were performed for cord artery pH, amplitude-integrated electroencephalography (aEEG), stage of HIE, and death or sequelae up to an age of 6 years. Parametric and non-parametric statistics were used with a two-sided p < 0.05 considered significant.Results: Among controls no associations between biomarker concentrations and gestational age, birthweight, length of storage of cord sera and degree of hemolysis were found. No significant differences in biomarker concentrations were found between HIE neonates and controls, and no differences were found with regard to HIE stage, cord acidemia, severity of aEEG changes, or persistent sequelae or death.Conclusions: No differences in cord blood UCH-L1 and GFAP concentrations were found between HIE neonates and controls, and no associations were found between the biomarker concentrations and the severity of disease, or whether the condition developed into a permanent or fatal injury.

Ultra high performance liquid chromatography coupled to tandem mass spectrometry determination of lipid peroxidation biomarkers in newborn serum samples

Byproducts of arachidonic (AA) and docosahexaenoic acid (DHA) oxidation are highly relevant for the study of free radical associated conditions in the perinatal period. Plasma metabolites can provide the clinician with a snapshot of the oxidant status of patients before and after specific clinical interventions (e.g.: supplementation with oxygen). We describe a new andreliable ultra-performance liquid mass spectrometry method to determine F2-isoprostanes and other byproducts (isoprostanes, isofurans, neuroprostanes, neurofurans) in newborn serum samples. Cord blood samples were obtained from severely depressed newborn infants (Apgar score 1 min < 3; arterial cord pH < 7.00), and aliquoted for serum determination and stored at −80 °C. A UHPLC-MS/MS method was employed. It has a series of technical advantages: simple sample treatment; reduced sample volume (100 μL) which is essential for preterm neonates with low circulating blood volume, high throughput of sample analysis (96 samples in less than 24 h) and high selectivity for different isoprostanes isomers. Excellent sensitivity was achieved within limits of detection between 0.06 and 4.2 nmol L−1, which renders this method suitable to monitoranalyte concentration in newborn samples. The method's precision was satisfactory; with coefficients of variation around 5–12% (intra-day) and 7–17% (inter-day). The reliability of the described method was assessed by analysis of spiked serum samples obtaining recoveries between 70% and 120%. The proposed method has rendered suitable for serum determination for newborn babies at risk of oxygen free radical associated conditions.

Perinatal Outcome in 1515 Cases of Prolonged Second Stage of Labour in Nulliparous Women.

To examine perinatal outcomes among nulliparous women with a second stage of labour lasting more than three hours. We conducted a retrospective review of all nulliparous women over a 14-year period who had a term, live, singleton, cephalic fetus ≥ 2500 g and who had a second stage of labour lasting at least three hours. Outcome measures included five-minute Apgar score < 7, cord arterial pH < 7.10, admission to the NICU, neonatal seizures, and neonatal death. Rates of serious long-term neurologic morbidity were also analyzed. Outcomes were compared with those of a similar cohort of women who delivered after less than three hours in the second stage. During the study period, 1515 women met the inclusion criteria. The majority of women (67%) delivered vaginally, after up to 10 hours in the second stage of labour. The overall rate of Caesarean section was low (15.7%). The rate of permanent neurologic impairment was 2.6 per 1000 deliveries. Among nulliparous women, 84% were spared a possibly difficult Caesarean section in the second stage of labour or a potentially difficult operative vaginal delivery by allowing a longer second stage. However, surviving neonates had a higher risk of permanent neurologic handicap. Our study indicates that the optimal management of the second stage of labour remains controversial.

Short-Term Variation of the Fetal Heart Rate for Predicting Neonatal Acidosis in Preeclampsia

Introduction: The aim of this study was to measure the performance of short-term variation (STV) in predicting the onset of neonatal acidosis in fetuses at risk due to maternal preeclampsia. Material and Methods: This retrospective study examined data from a series of 159 women with singleton pregnancies, hospitalized for preeclampsia in a level 3 reference maternity hospital in northern France, with an STV measurement in the 24 h preceding cesarean delivery and a measurement of the newborn's arterial cord pH at birth. The main outcome was determined by a correlation between STV and neonatal pH. Results: The last computerized fetal heart rate analysis took place a mean of 7.9 ± 6.3 h before birth, and neonatal acidosis was diagnosed in 38 newborns (23.9%). Although STV and umbilical artery pH at birth were significantly correlated (ρ = 0.16, p < 0.05), the performance of STV in predicting neonatal acidosis was poor, with an area under the ROC curve of 0.63. The sensitivity reached only 50.0% and the specificity 71.9% at the best STV threshold for predicting acidosis. Conclusion: The performance of STV for screening for neonatal acidosis is poor in women with preeclampsia. The divergent results between studies are probably due to the variable intervals between STV measurement and birth.

Mode of delivery of twin gestation with very low birthweight: is vaginal delivery safe?

The purpose of this study was to determine whether planned vaginal delivery is associated with increased risk of perinatal death and morbidity in twin pregnancies that are complicated by a very low birthweight of the second twin. We conducted a retrospective cohort study of twin pregnancies in which the second twin's birthweight was ≤1500 g. One hundred ninety-three twin gestations met the study criteria; patients were classified into 2 groups according to the planned mode of delivery: (1) cesarean delivery (n = 142) and (2) vaginal delivery (n = 51). In the vaginal delivery group, 21 pairs were in cephalic-cephalic presentation at the time of delivery; 28 pairs were cephalic-noncephalic, and 2 pairs were noncephalic-noncephalic. Composite adverse neonatal outcome was defined as the presence of neonatal death, respiratory distress syndrome, sepsis, necrotizing enterocolitis, or intraventricular hemorrhage grade 3-4. Trial of vaginal delivery was successful for both twins in 90.5% of cephalic-cephalic twins and 96.4% in cephalic-noncephalic twins. The rate of intraventricular hemorrhage was significantly higher in the vaginal delivery group (29.4% vs 8.5%, respectively; P = .013; adjusted odds ratio [OR], 3.65; 95% confidence interval [CI], 1.32-10.1). The increased risk of intraventricular hemorrhage in the vaginal delivery groups was evident in both twin A (17.6% vs 7.0%; P = .029) and twin B (15.7% vs 4.9%; P = .014); however, these differences were not significant after adjustment for possible confounders (twin A: adjusted OR, 1.79; 95% CI, 0.58-5.55; twin B: adjusted OR, 2.13; 95% CI, 0.63-7.25). In addition, subgroup analysis revealed that both cephalic-cephalic and cephalic-noncephalic twins who were delivered vaginally had increased risk for intraventricular hemorrhage. There were no significant differences between the cesarean and vaginal delivery groups in the rates of Apgar score <7 at 5 minutes, arterial cord pH <7.1, composite adverse neonatal outcome, and neonatal mortality rate. However, the rate of respiratory distress syndrome was significantly lower in the vaginal delivery group (66.7% vs 69%; P = .042; OR, 0.34; 95% CI, 0.12-0.96). Vaginal delivery of very low birthweight twins is associated with an increased risk of intraventricular hemorrhage, regardless of presentation. Because of the small sample size and the retrospective cohort design, large prospective randomized studies are needed.

Teenage Pregnancies: Obstetric and Neonatal Outcomes at a Danish Regional Hospital

Objective: The aim of our study was to investigate whether Danish teenage pregnancies were associated with increased risks of adverse maternal, obstetrical and neonatal outcomes. Study design: A retrospective case control study. All nulliparous singleton pregnant teenagers ≤ 19 years (n=134) and randomly selected nulliparous women (n=268) aged 20-39 with singleton pregnancy, who gave birth at the Regional Hospital of Randers from 2008 to 2012 were included. Statistical comparisons by independent t-test were applied to continuous data, while Chi-square test was used to examine for differences in frequency data. We calculated Odds ratio (OR), 95% confidence intervals (CI) and p values <0.05 was considered significant. Results: The prevalence of teenage pregnancy in our study was 1.8%. Smoking during pregnancy was significantly higher among pregnant teenagers (46%) versus non-teenagers (9%). There was a significantly higher prevalence of spontaneous vaginal delivery in teenage pregnancies (81%) compared to controls (65%). The prevalence of caesarean section was significantly lower in the study group (6.7%) than in the control group (19%). Third and fourth degree perineal tears and postpartum hemorrhage were significantly less in the study group than in the control group (0.8% vs 6.4% and 16% vs 25.4% respectively). There was no statistically significant association between teenage pregnancies and increased rates of antenatal complications including, preeclampsia, eclampsia and gestational diabetes mellitus. There was no statistical significant difference of the neonatal outcomes; LBW, Apgar score and arterial cord pH between groups. Conclusion: Teenage pregnancies in our setting seem not to be associated with increased risks of adverse maternal, obstetrical and neonatal outcomes. This is probably due to high-quality maternity and neonatal care that is available for teenage pregnancies in Denmark.

Usefulness of fetal urine production measurement for prediction of perinatal outcomes in uteroplacental insufficiency.

To evaluate whether fetal urine production measurement is useful for predicting adverse outcomes in patients with uteroplacental insufficiency. We enrolled patients with uteroplacental insufficiency at 24 to 40 weeks' gestation and normal pregnancies matched for gestational age and divided them into 3 groups according to perinatal outcomes: group 1 (n = 141), a control group of normal pregnancies; group 2 (n = 29), uteroplacental insufficiency without adverse outcomes; and group 3 (n = 18), uteroplacental insufficiency with adverse outcomes. An adverse outcome was defined as 1 or more of the following: (1) cesarean delivery because of fetal distress; (2) admission to the neonatal intensive care unit; (3) cord arterial pH less than 7.15 at birth; and (4) low 5-minute Apgar score (<7). The fetal urine production rate was obtained by serial bladder volume measurement using virtual organ computer-aided analysis. For bladder volume determination, we scanned the bladder in the 3-dimensional mode and defined the bladder surface contour in the reference plane, repeating the rotation of the reference plane with an angle of 30° and determining the surface contour on each plane. Statistical methods, including the Mann-Whitney U test, Fisher exact test, χ(2) test, and Kruskal-Wallis analysis of variance, were used. Group 3 had a lower mean fetal urine production rate than groups 1 and 2, whereas the urine production rate was not different between groups 1 and 2 (group 1, 49.0 mL/h; group 2, 59.4 mL/h; group 3, 20.7 mL/h; P < .001 between groups 1 and 3 and between groups 2 and 3). This difference between groups 2 and 3 remained significant after adjusting for the amniotic fluid index, umbilical artery Doppler pulsatility index, and presence of fetal growth restriction. Uteroplacental insufficiency cases with adverse perinatal outcomes had a lower fetal urine production rate than those without adverse outcomes. This difference might be used to predict adverse perinatal outcomes in uteroplacental insufficiency.

Automated auditory brainstem response in preterm newborns with histological chorioamnionitis

Objective: We investigated whether histological chorioamnionitis is associated with an adverse neonatal hearing outcome.Methods: Two cohorts of very preterm newborns (n = 548, gestational age ≤ 32.0 weeks) were linked to placental histology and automated auditory brainstem response (AABR) outcome.Results: In multivariable analyses, an abnormal AABR was not predicted by the presence of histological chorioamnionitis, either with or without fetal involvement (OR 1.4, 95% CI 0.5 – 3.8, p = 0.54 and OR 1.1, 95% CI 0.4–3.0, p = 0.79, respectively). Significant predictors of abnormal AABR included, e.g. birth weight (per kg increase: OR 0.2, 95% CI 0.0–0.6, p = 0.006), umbilical cord artery pH (per 0.1 increase: OR 0.7, 95% CI 0.5–0.9, p = 0.005) and mechanical ventilation (OR 3.7, 95% CI 1.2–11.6, p = 0.03).Conclusions: Histological chorioamnionitis was not associated with an adverse neonatal hearing outcome in two cohorts of very preterm newborns. Indicators of a complicated neonatal clinical course were the most important predictors of an abnormal hearing screening.

The Incidence of Maternal Artefact During Intrapartum Fetal Heart Rate Monitoring

ObjectiveTo determine the incidence of maternal heart rate artefact (MHRA) when monitoring fetal heart rate (FHR) in labour and to determine obstetrical factors associated with MHRA. MethodsIn a prospective observational study, maternal and fetal heart rates were displayed simultaneously to document the superimposition of the maternal heart rate (MHR) on FHR tracings. All women in labour who were undergoing external fetal monitoring (EFM) at the Ottawa Hospital from October 2011 to March 2012 were eligible. Every episode of MHRA was documented and classified according to its clinical significance. Wilcoxon test, t tests, and chi-square tests were used to identify time-related differences and obstetrical factors (epidural analgesia, fetal presentation, multiple gestation, maternal BMI, umbilical cord arterial pH, five-minute Apgar scores) that were associated with a potential adverse outcome. ResultsWe assessed 1313 tracings with simultaneous displays of the MHR and FHR in labour. MHRA was present at least once in 721 tracings (55%). Of these tracings, 35 were classified as having one or more episodes that might have led to an adverse outcome (either false positive or false negative), giving an incidence of 2.7% of all women in labour. In 33 tracings, the MHRA masked an abnormal FHR tracing. In two tracings, the MHRA masked a normal FHR, which might have resulted in misinterpretation of the tracing (i.e., false positive), leading to unnecessary intervention. ConclusionThe incidence of MHRA is higher than currently thought, and in more than 2% of women in labour may lead to adverse outcomes. We propose routine use of simultaneous maternal and FHR monitoring for women undergoing EFM, especially during the second stage of labour.

Neonatal morbidity associated with shoulder dystocia maneuvers

We sought to examine neonatal morbidity associated with different maneuvers used among term patients who experience a shoulder dystocia. We conducted a retrospective cohort study of all women who experienced a clinically diagnosed shoulder dystocia at term requiring obstetric maneuvers at a single tertiary care hospital from 2005 through 2008. We excluded women with major fetal anomaly, intrauterine death, multiple gestation, and preterm. Women exposed to Rubin maneuver, Wood's screw maneuver, or delivery of the posterior arm were compared to women delivered by McRoberts/suprapubic pressure only, which served as the reference group. The primary outcome was a composite morbidity of neonatal injury (defined as clavicular or humeral fracture or brachial plexus injury) and neonatal depression (defined as Apgar <7 at 5 minutes, arterial cord pH <7.1, continuous positive airway pressure use, intubation, or respiratory distress). Logistic regression was used to adjust for nulliparity and duration of shoulder dystocia, defined as time from delivery of fetal head to delivery of shoulders. Among the 231 women who met inclusion criteria, 135 were delivered by McRoberts/suprapubic pressure alone (57.9%), 83 women were exposed to Rubin maneuver, 53 women were exposed to Wood's screw, and 36 women were exposed to delivery of posterior arm. Individual maneuvers were not associated with composite morbidity, neonatal injury, or neonatal depression after adjusting for nulliparity and duration of shoulder dystocia. We found no association between shoulder dystocia maneuvers and neonatal morbidity after adjusting for duration, a surrogate for severity. Our results demonstrate that clinicians should utilize the maneuver most likely to result in successful delivery.

PO-0732 Hypocarbia In Hypoxic-ischaemic Encephalopathy: Are We Bad With Good Lungs?

Background and aims Hypoxic-ischaemic encephalopathy (HIE) is an important cause of cerebral damage and long-term neurological sequelae. Over-ventilation in infants with HIE can lead to hypocarbia and consequent cerebral vasoconstriction further increasing the risk of brain injury. Our aim was to assess the incidence of hypocarbia in HIE and identify infants at increased risk of hypocarbia. Methods Retrospective review of term admissions with HIE to a tertiary neonatal intensive care unit from 2008 to 2013. Hypocarbia was defined as a partial blood pressure of CO 2 (pCO 2 ) ≤ 4 kPa. Results 74 infants were reviewed. The median (interquartile range) gestational age was 40 (38–41) weeks. 47 (64%) were actively cooled. Arterial cord pH was 6.99 (6.80–7.10). 40 (54%) infants had hypocarbia on day 1: pCO 2 was 3.35 (2.84–3.73) kPa and duration of hypocarbia was 160 (120–300) minutes. 48 (64.9%) were ventilated: 11 (22.9%) with volute targeted-ventilation, 36 (75.0%) with non-volume-targeted ventilation and 1 (1.4%) with high-frequency oscillation. Lowest CO 2 was not significantly different but duration of hypocarbia was significantly longer (p 2 Conclusions Hypocarbia is frequently encountered in HIE. Mechanical ventilation of infants with HIE should aim to avoid hypocarbia by applying “neuroprotective” ventilation strategies such as volume-targeted ventilation.

PO-0407 Perinatal Factors And Perinatal Arterial Ischaemic Stroke (pais): A Prospective Case-control Study

Background Perinatal factors (PF) have been implicated in the pathogenesis of PAIS. Hypoxia has been suggested to be involved as a potential cause of AIS although prospective case-control studies are still warranted. Objective To determine the impact of PF on neonatal cases diagnosed of PAIS in a prospective case-control study. Methods 45 neonates were diagnosed of PAIS within four weeks of life and 85 controls were investigated for the following PF: retarded intrauterine growth restriction, sentinel event, epidural and general anaesthesia, presentation at delivery, type of delivery (vaginal, instrumental, emergency caesarean section), abnormal cardiotocographic monitoring, Apgar score at 1 and 5 min, arterial umbilical cord pH Results The univariate analysis indicated the following associations with PAIS: emergency caesarean section (48.9% vs 14.8%; p A multivariate analysis did not show any independent factor associated to PAIS, except for arterial cord pH Conclusion Our data indicate that PF do not appear to play a major role in PAIS.

Defining an Abnormal First Stage of Labor Based on Maternal and Neonatal Outcomes

Objective The objective of the study was to determine the threshold for defining abnormal labor that is associated with adverse maternal and neonatal outcomes. Study Design This study consisted of a retrospective cohort of all consecutive women admitted at a gestation of 37.0 weeks or longer from 2004 to 2008 who reached the second stage of labor. The 90th, 95th, and 97th percentiles for progress in the first stage of labor were determined specific for parity and labor onset. Women with a first stage above and below each centile were compared. Maternal outcomes were cesarean delivery in the second stage, operative delivery, prolonged second stage, postpartum hemorrhage, and maternal fever. Neonatal outcomes were a composite of the following: admission to level 2 or 3 nursery, 5 minute Apgar less than 3, shoulder dystocia, arterial cord pH of less than 7.0, and a cord base excess of –12 or less. Results Of the 5030 women, 4534 experienced first stage of less than the 90th percentile, 251 between the 90th and 94th percentiles, 102 between the 95th and 96th percentiles, and 143 at the 97th percentile or greater. Longer labors were associated with an increased risk of a prolonged second stage, maternal fever, the composite neonatal outcome, shoulder dystocia, and admission to a level 2 or 3 nursery ( P Conclusion Although women who experience labor dystocia may ultimately deliver vaginally, a longer first stage of labor is associated with adverse maternal and neonatal outcomes, in particular shoulder dystocia. This risk must be balanced against the risks of cesarean delivery for labor arrest.

The Association of Maternal Obesity With Fetal pH and Base Deficit at Cesarean Delivery

OBJECTIVE To evaluate the association between maternal body mass index (BMI) and umbilical cord acid-base status at the time of cesarean delivery. METHODS We conducted a retrospective multicenter cohort study using data from the Cesarean Section Registry of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Women were included if they delivered a live, nonanomalous singleton at 37-41 weeks of gestation by prelabor cesarean under spinal anesthesia. We excluded women with diagnoses that might be associated with uteroplacental insufficiency. Body mass index at delivery was examined both as a continuous and categorical exposure, and acid-base status was based on cord arterial pH and base deficit. RESULTS There were 5,742 mother-neonate pairs who met criteria for analysis. Among possible confounders (including sociodemographic variables, number of previous uterine incisions, diabetes, hematocrit, neonatal gender, and birth weight), African American race, birth weight, parity, and smoking status were significantly associated with both BMI and acid-base parameters. Adjusted for those four factors, with increasing BMI category (less than 25, 25-29.9, 30-34.9, 35-39.9, and 40 or higher), mean pH decreased from 7.25 to 7.22 (P<.001), proportion with pH less than 7.1 increased from 3.5% to 7.7% (P=.011), mean base deficit increased from 4.01 mmol/L to 4.83 mmol/L (P=.030), and proportion with base deficit of 12 mmol/L or more increased from 0.6% to 4.7% (P=.003). When BMI was analyzed continuously and adjusted for these confounders, for every 10-unit increase in BMI, cord arterial pH decreased by 0.01 (P<.001) and base deficit increased by 0.26 mmol/L (P=.005). CONCLUSION For women undergoing nonemergent prelabor cesarean delivery under spinal anesthesia, fetal pH declines and base deficit rises as maternal BMI increases. LEVEL OF EVIDENCE II.

The effects of epidural/spinal opioids in labour analgesia on neonatal outcomes: a meta-analysis of randomized controlled trials.

Epidural/spinal opioids are increasingly used to relieve parturients' pain in labour. Some studies indicate that opioids can induce side effects in neonates, such as respiratory depression and neurobehavioural changes. This meta-analysis aimed to clarify the effects of opioids in labour analgesia on neonates. PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and EMBASE™ were searched for relevant randomized controlled trials (RCTs). The neonatal data of Apgar scores, Neurological and Adaptive Capacity Scores (NACS), and umbilical cord pH values were extracted. Statistical analyses were carried out using Review Manager 5.2 and Stata(®) 10. Twenty-one trials with 2,859 participants were included in our meta-analysis. No difference in the incidence of Apgar scores < 7 was shown between the opioid and control groups at one minute (risk difference [RD] 0.0%, 95% confidence interval [CI]: -3.0 to 2.0, P = 0.78; I (2) = 0%, 95% CI: 0 to 50) and at five minutes (RD -1.0%, 95% CI: -2.0 to 1.0, P = 0.31; I(2) = 0%, 95% CI: 0 to 50). No significant differences were found in the NACS at two hours (mean difference [MD] -0.35, 95% CI: -1.70 to 1.01, P = 0.62; I(2) = 0%, 95% CI: 0 to 79) and at 24 hr (MD -0.45, 95% CI: -1.36 to 0.46, P = 0.33; I(2) = 3%, 95% CI: 0 to 26). Also, no significant differences were found in umbilical cord artery pH (MD -0.02, 95% CI: -0.06 to 0.03, P = 0.48; I(2) = 80%, 95% CI: 46 to 92) and vein pH (MD -0.03, 95% CI: -0.07 to 0.00, P = 0.08; I(2) = 77%, 95% CI: 36 to 91). No significant publication bias was found. The common doses of fentanyl and sufentanil used with an epidural/spinal technique in labour analgesia are safe for neonates up to 24 hr after delivery. In future studies, more attention should be paid to the long-term side effects in neonates.