Neonatal Umbilical Artery pH Research Articles

Perioperative Supplemental Oxygen for the Prevention of Surgical Site Infection After Cesarean Section: A Systematic Review of Existing Literature.

Initial systematic reviews demonstrated the reduction of surgical site infection (SSI) following perioperative oxygen supplementation. SSI among colorectal surgeries was reduced by more than 50% with high-flow oxygen. However, recent randomized trials are coming up with conflicting results. The objective of this review was to comprehend whether the application of perioperative supplemental oxygen decreased the hazard of SSI following cesarean delivery.The initial search identified 95 studies. After screening title and abstracts 59 studies were included, and 33 studies were found to be relevant after checking eligibility. After a careful analysis, five articles were found fit for this systematic review. Extracted information included study design and methodology, the cumulative incidence of post-cesarean SSI following supplemental oxygen, the odds ratio, and associated variability for all factors considered in univariate and/or multivariate analysis. The cumulative incidence of the standard care group and supplemental oxygen group were comparable in all five studies with statistically significant differences. The secondary outcomes such as hospital readmission, wound separation, and intravenous antibiotics were similar in both groups as stated in the two studies. The rate of SSI in diabetics was 6.9% and 14.4% in the standard care group and supplemental oxygen group, respectively, as analyzed in a study. An increase in intra-operative blood loss was found to be the major risk factor leading to SSI. In one of the studies, Caucasian race, increased basal metabolic index, and prolonged surgery were associated with increased risk of SSI. There was no difference in neonatal umbilical artery pH resulting from supplemental oxygen during cesarean.The available literature is quite sufficient to prove that supplemental oxygen offers no added benefit in reducing post-cesarean SSI. Hence, we do not recommend its use for this purpose.

Intravenous ondansetron for the prevention of supine hypotensive syndrome during spinal anesthesia for cesarean section: a randomized controlled trial.

Background: Supine hypotensive syndrome is a common complication in late pregnancy. This study aims to explore the effects of ondansetron on the prevention of supine hypotensive syndrome during spinal anesthesia for cesarean section. Methods: A total of 80 women undergoing elective cesarean delivery were randomly assigned to two groups (the ondansetron group and the control group), with 40 cases in each group. The ondansetron group received 0.075mg/kg of ondansetron intravenously 5min before the induction of spinal anesthesia; the control group was given the same volume of saline solution. The blood pressure and heart rate were measured. Umbilical artery pH was analyzed, and the incidence of nausea and vomiting and vasoconstrictor drug usage were noted. Results: The incidence of supine hypotensive syndrome, nausea and vomiting, and vasoconstrictor drug use were significantly lower in the ondansetron group than the control group (2.5% vs. 20%, p = 0.029; 2.5% vs. 22.5%, p = 0.007; and 5% vs. 22.5%, p = 0.012, respectively). Umbilical artery pH was higher in the ondansetron group than the control group, and statistical significance was observed (7.31 ± 0.03 vs. 7.28 ± 0.04, p = 0.002). The maternal hemodynamic parameters and the neonatal Apgar score were similar between the two groups. Conclusion: Ondansetron can effectively prevent supine hypotensive syndrome, reduce the incidence of nausea, vomiting, and vasoconstrictor drug use, and improve neonatal umbilical arterial pH during spinal anesthesia for cesarean section. Clinical Trial Registration: https://www.chictr.org.cn/, identifier ChiCTR180018756.

Added value of the pulmonary vein pulsatility index and its correlation to neonatal umbilical artery pH in fetal growth restrictions: a Vietnamese matched cohort study

BackgroundIn clinical obstetrics, many guidelines recommended the use of Doppler fetal ductus venosus blood flow to monitor and to manage fetal growth restriction (FGR). The ductus venosus and the pulmonary venous flow pattern of fetuses are similar. Umbilical artery pH (UA pH) is essential in identifying adverse pregnancy outcomes, particularly in fetal growth restriction cases. Nevertheless, the literature indicates that the relationship between pulmonary vein pulsatility index (PVPI) and UA pH in FGR cases has not been well investigated. This study aimed to identify the alteration in PVPI in FGR cases and evaluate the correlation between PVPI and UA pH in FGR newborns.MethodsThis matched cohort study of singleton pregnancies from 28+ 0 to 40+ 0 weeks of gestation without congenital abnormalities included 135 cases of FGR (disease group) and 135 cases of normal growth (control group). The PVPI was measured at the proximal segment of the right or left pulmonary vein, approximately 5 mm from the left atrium wall. The umbilical artery pulsatility index (UAPI) was measured on the free umbilical cord. An elective cesarean section or labor induction are both options for ending the pregnancy, depending on the condition of the mother or fetus. Umbilical artery blood samples were collected within 5 min of delivery for UA pH measurement. SPSS version 20 and Medcalc version 20.1 were used for data analysis.ResultsFGR cases had a significantly higher mean fetal PVPI than the control group (1.16 ± 0.26 vs. 0.84 ± 0.16; p < 0.01), and PVPI and UAPI were positively correlated (r = 0.63; p < 0.001). PVPI and UA pH were negatively correlated in FGR patients, with r = -0.68; p < 0.001. The PVPI value on the 95th percentile had a prognostic value of UA pH < 7.20 with a sensitivity of 88.2%, specificity of 66.3%, positive predictive value of 46.9%, and negative predictive value of 94.3%.ConclusionsThere was a statistically significant difference in PVPI values in FGR cases compared to the normal growth group, a positive correlation between PVPI and UAPI, and a negative correlation between PVPI and UA pH. PVPI might have a prognostic meaning in predicting UA pH at birth.

The Association of Anesthesia Type and Neonatal Outcomes Following Category-1 Cesarean Delivery: A Retrospective Cohort Study.

Objectives Neuraxial anesthesia is the preferred anesthesia technique for cesarean delivery due to a decreased risk of adverse events. However, general anesthesia is often employed during emergent cesarean deliveries to achieve a shorter decision-to-delivery interval. The objective of this study was to determine if the conversion of epidural labor analgesia to surgical anesthesia for a category-1 cesarean delivery is associated with significant neonatal morbidity. Study design This was a retrospective cohort study of all intrapartum category-1 cesarean deliveries performed at an academic tertiary care institution between August 2016 and July 2021. The primary outcome was neonatal morbidity, defined as a composite of neonatal umbilical artery pH < 7.10 and/or 5-min Apgar score < 7, and/or neonatal intensive care unit admission. A multivariate regression analysis was performed to control for the presence of covariates and examine the degree to which they influenced the outcome. Results A total of 185 mother-neonate pairs qualified for inclusion, of which 23 had cesarean delivery under general anesthesia and 162 under epidural anesthesia. There was no significant difference in adverse neonatal outcomes between category-1 cesarean deliveries done under general anesthesia compared to epidural anesthesia (47% vs 35%,p = 0.3). The incidence of umbilical arterial pH < 7.10 was higher in the general anesthesia group compared to the epidural anesthesia group (35% vs 12%,p = 0.018). The multivariate regression model showed that gestational age (OR = 0.63; 95% CI = 0.51-0.75, p = <0.001) and non-reassuring fetal heart trace (OR = 0.18; 95% CI = 0.05-0.58, p = 0.005) were significant predictors of adverse neonatal outcome. Conclusion Our results suggest that the conversion of epidural analgesia to surgical anesthesia for category-1 cesarean delivery in women with a functional labor epidural catheter is not associated with poorer neonatal outcomes.

Cerebroplacental ratio (CPR) and reduced fetal movement: predicting neonatal outcomes

Objective The aim of this study was to evaluate the role of cerebroplacental ratio (CPR) in term pregnancies with reduced fetal movements (RFM) and appropriate for gestational age (AGA)fetuses to predict poor neonatal outcomes. Methods A prospective cohort study was performed on 150 singleton pregnancies with gestational age of 37–41 weeks and multiple episodes of RFM (case group) and 150 pregnancies within the same criteria only without RFM (control group). Both groups had appropriate for gestational age (AGA)fetuses. Umbilical artery (UA) and middle cerebral artery (MCA) pulsatility indices (PI) were measured, and MCA to UA ratio (CPR) was calculated. Doppler indices and neonatal outcomes were compared between the two groups. Independent prediction role of CPR MoM was evaluated through a binary logistic regression method. Results The RFM group had significantly higher UA- PI MoM (1.01 ± 0.19 versus 0.86 ± 0.05, p < .001), lower MCA MoM (1.28 ± 0.20 versus 1.40 ± 0.13, (p < .001)) and lower CPR MoM (0.98 ± 0.24 versus 1.23 ± 0.12, (p < .001)) compared to the control group. Mean umbilical artery pH was lower in the RFM group and the frequency of neonatal UA cord pH <7.2 was higher in the RFM group. In RFM group, CPR MoM showed a significant linear correlation with birth weight centiles (r = 0.244, p = .003), umbilical artery pH (r = 0.319, p < .001) and Apgar score at minute 1 (r = 0.332, p < .001). CPR MoM exhibited negative correlation with duration of NICU stay (r= −0.187, p = .022). No similar correlation was observed in the control group. In binary logistic regression analysis, CPR MoM was adjusted for the results of NST; and it was concluded that CPR MoM was the only significant predictor of Apgar score minute 1 = <7 (OR: 0.004; 95% CI: 0.0002–0.0673, p < .001), umbilical artery ph <7.2 (OR: 0.019; 95% CI: 0.00005–0.0423, p < .001) and NICU admission (OR: 0.116; 95% CI: 0.018–0.744, p = .023). In multivariate binary logistic regression analysis included parity, history of abortion and ART, AFI, BPP and CPR MoM; the AFI (OR: 0.976; 95% CI: 0.957–0.995, p = .014), BPP (OR: 0.306; 95% CI: 0.172–0.545, p < .001) and CPR MoM (OR: 0.00005 95% CI: 0.000003–0.00061, p < .001) were the significant predictor of RFM. Area under the curve in receiver operating characteristics (ROC) curve was calculated as 0.828 for CPR MoM as a predictor of RFM (SE: 0.024, p < .001), yielding sensitivity and specificity estimates of 80.0% and 65.0%, respectively, using an optimal cutoff level of = < 1.19. Conclusion This study concluded that reduced fetal movement was significantly related to low CPR MOM. Also, it showed the independent role of CPR MoM for prediction of lower neonatal umbilical artery pH, lower Apgar score minute 1 and higher rate of NICU admission in AGA term fetuses without considering NST results. Also, AFI, BPP and CPR MoM are significant predictors of RFM.

Near-infrared spectroscopy of the placenta for monitoring fetal oxygenation during labour.

Although being the golden standard for intrapartum fetal surveillance, cardiotocography (CTG) has been shown to have poor specificity for detecting fetal acidosis. Non-invasive near-infrared-spectroscopy (NIRS) monitoring of placental oxygenation during labour has not been studied yet. The objective of the study was to determine whether changes in placental NIRS values during labour could identify intrapartum fetal hypoxia and resulting acidosis. We included 43 healthy women in active stage of labour at term. CTG and NIRS parameters in groups with vs. without neonatal umbilical artery pH ≤ 7.20 were compared using Mann-Whitney-U. Receiver-operating-characteristics (ROC) curves were used to estimate predictive value of CTG and NIRS parameters for neonatal pH ≤ 7.20. A computer-based statistical classification was also performed to further evaluate predictive values of CTG and NIRS for neonatal acidosis. Ten (23%) neonates were born with umbilical artery pH ≤ 7.20. Compared to group with pH > 7.20, fetal acidosis was associated with more episodes of placental NIRS deoxygenation (9 (range 2-37) vs. 2 (range 0-65); p<0.001), higher velocity of placental NIRS deoxygenation (2.31 (range 0-22) vs. 1 (range 0-49) %/s; p = 0.03), more decelerations on CTG (25 (range 3-91) vs. 10 (range 10-60); p = 0.02), and more prolonged decelerations on CTG (2 (range 0-4) vs. 1 (range 0-3); p = 0.04). Number of placental deoxygenations had the highest prognostic value for fetal/neonatal acidosis (area under the ROC curve 0.85 (95% confidence interval 0.70-0.99). Computer-based classification also identified number of placental deoxygenations as the most accurate classifier, with 25% false positive and 93% true positive rate in the training dataset, with 100% accuracy when applied to the testing dataset. Placental deoxygenations during labour measured by NIRS are associated with fetal/neonatal acidosis. Predictive value of placental NIRS for neonatal acidosis was superior to that of CTG.

Time From Neuraxial Anesthesia Placement to Delivery is Inversely Proportional to Umbilical Arterial Cord pH at Scheduled Cesarean Delivery

(Am J Obst Gynecol. 2019;220:389.e1–389.e9) While the maternal risks of cesarean delivery are well documented in the literature, less is known about the risks to the fetus. Neuraxial block-related hypotension and maternal obesity have been found to contribute to uterine hypoperfusion and umbilical arterial pH depression. Examining the time between spinal anesthesia placement and delivery could provide insight into these risks to the fetus awaiting cesarean delivery. The aim of this study was to evaluate neonatal umbilical arterial pH in relation to predelivery time intervals during scheduled cesarean delivery.

The effects of prophylactic infusing ephedrine combined with phenylephrine versus ephedrine alone in maternal and neonate undergoing spinal anesthesia for cesarean section: A Meta-analysis of randomized trials

Objective Used a Meta-analysis to evaluate the effects of prophylactic infusing ephedrine alone or combined with phenylephrine on maternal hemodynamics and neonatal blood gas analysis undergoing spinal anesthesia for cesarean section. Methods Randomized controlled trial(RCT) about the effects of prophylactic infusing ephedrine alone or combined with phenylephrine on maternal and neonate undergoing spinal anesthesia for cesarean section were retrieved from Cochrane Library, PubMed, Embase, Wangfang Database, CNKI and SinoMed from the date of their establishment to September, 2017. The documents were screened and the relevant data were extracted according to the inclusion criteria. The methodological quality of the included RCT was evaluated by Jadad scale. Using RevMan 5.3 software for Meta-analysis. Continuous variables were dealt with mean differences(MD) and 95% confidence intercal(CI), and the dichotomous variables were dealt with odd ratio(OR) and 95%CI. Descriptive analysis of the RCTs which is not available for Meta-analysis. Results We identified 9 RCTs including 590 patients, including 5 RCTs in English and 4 RCTs in Chinese. Among them, 294 patients were in the ephedrine group(E group) while 296 patients were in the ephedrine combined with phenylephrine group(EP group). The results of Meta-analysis showed that the incidence of maternal hypotension [OR=0.49, 95%CI(0.3, 0.8), P<0.01], hypertension [OR=0.52, 95%CI(0.30, 0.92), P=0.02], nausea and vomiting [OR=0.32, 95%CI (0.19, 0.53), P<0.01] and the incidence of neonatal acidosis [OR=0.22, 95%CI(0.10, 0.49), P<0.01] were significantly lower in the ephedrine combined phenylephrine group than these parameters in the ephedrine alone groups. The neonatal umbilical artery pH [MD=0.1, 95%CI(0.07, 0.13), P<0.01], base excess(BE) [MD=2.24, 95%CI(0.78, 3.69), P<0.01], oxygen partial pressure(PO2) [MD=1.53, 95CI (0.08, 2.98), P<0.01] value in the ephedrine combined with phenylephrine group was significantly higher than those parameter in the ephedrine alone group. Moreover, the umbilical artery lactic acid [MD=-1.39, 95%CI (-1.73, -1.05), P<0.01], partial pressure of cardon dioxide(PCO2) [MD=-8, 95%CI(-13.2, -2.8), P<0.01] value were lower than those in the ephedrine alone group. The neonatal 1 min and 5 min Apgar score were not significant difference between the two groups. Conclusions Ephedrine combined with phenylephrine can prevent maternal hypotension undergoing spinal anesthesia for cesarean section and to maintain intraoperative hemodynamic stability. It also can reduce the incidence of maternal nausea and vomiting and neonatal acidosis. Key words: Ephedrine; Phenylephrine; Cesarean section; Hemodynamics; Heonate; Meta-analysis

Time from neuraxial anesthesia placement to delivery is inversely proportional to umbilical arterial cord pH at scheduled cesarean delivery

Neuraxial block-related hypotension and maternal obesity contribute to uterine hypoperfusion and decreased umbilical arterial pH at cesarean delivery. Between the time of anesthesia placement and delivery, the fetus may be exposed to a hypoperfused uterine environment without surgeon awareness of fetal compromise. We sought to evaluate neonatal umbilical arterial pH according to predelivery time intervals at scheduled term cesarean. We performed a retrospective cohort study of cesarean deliveries between September 2014 and February 2017. Singleton gestations undergoing scheduled cesarean delivery under spinal anesthesia between 37 and 41 weeks with a reassuring preoperative nonstress test were included. Time intervals between operative room entry, spinal anesthesia placement, skin incision, uterine incision, and delivery were calculated. The primary outcome was umbilical arterial pH. Demographic data, maternal blood pressures, predelivery time intervals, and delivery outcomes were analyzed according to umbilical arterial pH intervals of <7.0, 7.01-7.10, 7.11-7.20, 7.21-7.30, and >7.30. Umbilical cord gas analytes and neonatal outcomes were analyzed by spinal to delivery time. Stepwise linear regression was performed to identify predictors of decreasing umbilical arterial pH. Receiver-operator characteristic curves were calculated for spinal to delivery time and umbilical arterial pH <7.0 and 7.1. Among 527 included participants, median umbilical arterial pH was 7.27 [interquartile range, 7.23-7.29] and body mass index was 35 kg/m2 [interquartile range, 30-41]. Both maternal body mass index and hypotensive episodes increased with decreasing umbilical arterial pH (P <.001, P ≤ .02). All predelivery time intervals (operative room to delivery, spinal to skin, spinal to delivery, and uterine incision to delivery) increased as umbilical arterial pH interval decreased (P < .05 for all). In a stepwise linear regression, maternal body mass index, noncephalic presentation, spinal start to delivery interval, uterine incision to delivery interval, and maximum reduction in blood pressure from baseline were predictive of decreasing umbilical arterial pH after controlling for confounding variables (F [5,442]= 17.7, P= .0001], adjusted R2 of 0.157. When evaluated by spinal to delivery time, both umbilical arterial and venous pH and partial pressure of carbon dioxide decreased (P < .001 for all), but base deficit and neonatal outcomes were similar (P ≥ .7 for all). There were 2 cases of hypoxic-ischemic encephalopathy (0.38%). A receiver-operating characteristic curve demonstrated that a spinal start to delivery time greater than 27 minutes was associated with an umbilical arterial pH <7.1 (area under the curve, 0.74, 100% sensitivity, 21% specificity), and an interval greater than 30 minutes was associated with an umbilical arterial pH <7.0 (area under the curve, 0.80, 100% sensitivity, 33% specificity). Longer spinal-to-delivery and uterine incision-to-delivery time intervals were associated with decreasing umbilical arterial pH at scheduled term cesarean delivery. Efforts to minimize predelivery time following spinal placement could reduce the frequency of unanticipated neonatal acidemia.

Retrospective comparison of ephedrine and phenylephrine for the treatment of spinal anesthesia induced hypotension in pre-eclamptic patients

Objective: To compare neonatal acid base status in parturients who underwent cesarean delivery and received either ephedrine or phenylephrine boluses for the treatment of spinal anesthesia induced hypotension. Research design and methods: After institutional review board approval, the perioperative database of the University of Iowa Hospitals and Clinics was used to identify all women diagnosed with pre-eclampsia and had cesarean delivery under spinal anesthesia for the period 1 January 2005 to 31 July 2014. Data retrieved included patient demographics, indication for cesarean delivery, severity of pre-eclampsia, dose of vasopressor, neonatal umbilical artery pH and Apgar scores. Main outcome measures: Primary outcome was umbilical artery pH. Results: Data for 146 patients was included in the analysis. Ephedrine was used in 57 patients (group E) and phenylephrine in 89 (group PE) patients. The median umbilical artery pH was 7.30 (IQR 7.20–7.30) and 7.30 (IQR 7.20–7.30) in the ephedrine and phenylephrine groups respectively (P = 0.41). Non-reassuring fetal heart trace was the only factor significantly associated with lower umbilical artery pH on multivariable regression analysis (β = −0.09, P = 0.002). Conclusions: We found no difference in neonatal umbilical artery pH between ephedrine and phenylephrine when used to treat spinal anesthesia induced hypotension during cesarean delivery in pre-eclamptic patients. Limitations of the study include its retrospective single center design and the fact that the choice of vasopressor was not randomized.

Possible role of asymmetric dimethylarginine (ADMA) in prediction of perinatal outcome in preeclampsia and fetal growth retardation related to preeclampsia

Objective: The objective of this study is to investigate maternal serum and neonatal umbilical cord asymmetric dimethylarginine (ADMA) levels in prediction of perinatal prognosis in pregnancies with preeclampsia (PE) and fetal intrauterine growth retardation (IUGR) accompanying PE (PE + IUGR).Methods: Maternal serum ADMA (msADMA) and neonatal umbilical cord ADMA (ucADMA) levels were studied from 34 patients with PE, 25 patients with PE + IUGR, and 30 healthy pregnant controls in this prospective case–control study. Umbilical artery Doppler indices of fetuses, birth weights, Apgar scores, umbilical artery pH measurements of neonates, and admissions to neonatal intensive care unit (NICU) were recorded.Results: Median msADMA was significantly higher in PE and PE + IUGR groups (p = 0.024 and p = 0.011, respectively), and ucADMA was significantly higher in PE and PE + IUGR groups than the control group (p = 0.029 and p = 0.018, respectively). Median msADMA and ucADMA levels were significantly higher in the PE + IUGR group than the PE group (p = 0.019 and 0.021, respectively). ucADMA levels did not correlate with fetal umbilical arterial blood flow neither in the PE nor in the PE + IUGR group (p = 0.518 and p = 0.892, respectively). None was related with neonatal umbilical artery pH or NICU admission rates.Conclusions: msADMA and ucADMA correlated with severity of PE. msADMA and ucADMA failed to predict perinatal outcome in patients with PE and PE + IUGR.

Anesthetic technique for cesarean delivery and neonatal acid–base status: a retrospective database analysis

IntroductionA previous meta-analysis reported lower umbilical artery pH with spinal anesthesia for cesarean delivery compared to general or epidural anesthesia. Ephedrine was used in the majority of studies. The objective of this study was to evaluate the effect of anesthetic technique on neonatal acid–base status now that phenylephrine has replaced ephedrine in our institution. MethodsWe retrospectively reviewed our database to identify patients who underwent cesarean delivery and had umbilical artery pH available. We decided a priori to test separately cases where cesarean delivery was performed emergently (category I and II) or non-emergently (category III and IV). Multivariable models were constructed to detect significant predictors of lower umbilical artery pH. ResultsOne thousand sixty-four cases were included (647 emergent, 417 non emergent). In emergent cesarean delivery, anesthesia type was a significant predictor of lower umbilical artery pH (P <0.0001) with the pairwise comparisons showing lower neonatal umbilical artery pH [mean (95% CI)] with general anesthesia [7.16 (7.13, 7.19)] compared with spinal anesthesia [7.24 (7.22, 7.25)] and epidural anesthesia [7.23 (7.21, 7.24)], with no difference between spinal and epidural anesthesia. When excluding cases where general anesthesia was chosen due to insufficient time to place a neuraxial block or dose an existing epidural catheter, anesthesia type was not a predictor of lower umbilical artery pH. Anesthetic technique was not a predictor of lower umbilical artery pH in non-emergent cases. ConclusionsSpinal anesthesia was not associated with lower umbilical artery pH compared to other types of anesthesia. This might be due to the use of phenylephrine in our practice.

Remifentanil at induction of general anesthesia for cesarean section: Double blind, randomized clinical trial

Remifentanil, with its rapid activity onset and short duration of action, may be more effective than other opioids for providing hemodynamic stability during obstetric anesthesia. However, there is some evidence of adverse effects on neonatal respiratory function. We investigated maternal and fetal effects of Remifentanil during cesarean section surgery. Eighteen women with singleton term pregnancies, and physical class status of I or II as defined by the American Society of Anesthesia (ASA), who were undergoing general anesthesia for semi-elective cesarean section were randomized into two groups (40 in each group) that received either an intravenous bolus of 0.5 µg/kg Remifentanil or the same dose of saline as a placebo. Maternal hemodynamic variables and neonatal umbilical artery pH and Apgar score at first and fifth min were evaluated in both groups. Systolic and diastolic blood pressure were significantly lower after tracheal intubation and skin incision in the Remifentanil group as compared with the control group (p <0.05). There were no significant differences regarding heart rate between groups at any time (p > 0.05). Apgar scores at first and fifth min were not significantly different among groups (p>0.05). No neonate required assisted ventilation or naloxan administration. Remifentanil may be a safe and effective drug for the induction of general anesthesia and surgical stimulation without subsequent neonatal depression.

817: Indications for primary cesarean delivery and peripartum maternal and neonatal complications

816 Impact of obesity on cesarean Shayna Norman, Methodius Tuuli, Ryan Longman, Anthony Odibo, Alison Cahill Washington University in St. Louis, Obstetrics and Gynecology, St. Louis, MO OBJECTIVE: To evaluate the length of time from cesarean skin incision to infant delivery time and total operating time for women with increasing body mass index (BMI), and the possible effects of increased time from skin incision to delivery of the infant on neonatal acidosis. STUDY DESIGN: We performed a retrospective cohort study of all cesarean deliveries occurring at one institution from 2004-2008. Four comparison groups were defined by body mass index (BMI) 30 (n 768), 30-39.9 (n 1134), 40-49.9 (n 436), or 50 (n 205). Primary outcomes were time from skin incision to delivery and time from skin incision to skin closure. Secondary outcomes included umbilical arterial pH and base excess. RESULTS: Increasing BMI was associated with significantly increased time from skin incision to infant delivery and total operating time when compared to non-obese patients. Time from skin incision to delivery of the infant was 9.4 5.8 minutes for patients with BMI 30 vs. 15.9 11.2 minutes for patients with BMI 50, with a p-value 0.01. Neonatal umbilical arterial pH was lower and base excess was greater in obese patients undergoing cesarean. (Table) CONCLUSION: Increasing BMI is associated with a significantly increased time from skin incision to infant delivery, and the increased time may be associated with measures of neonatal acidosis. Cesarean technique remains to be optimized for obese women.

A comparison of intrapartum automated fetal electrocardiography and conventional cardiotocography—a randomised controlled study

Sir, We read with great interest the article by Ojala et al.1 The authors report that the incidence of metabolic acidosis after intrapartum monitoring by means of cardiotocography (CTG) supplemented by automatic ST analysis (STAN) of the fetal electrocardiogram is 1.7%, as compared with 0.7% after CTG alone. We wish to comment on the conclusion of the authors that CTG + STAN did not improve the neonatal outcome or decrease the caesarean section rate but that the need for fetal blood sampling (FBS) during labour was lower in the STAN group. In fact, although not statistically significant, there is a clinically relevant difference of 1% in the incidence of metabolic acidosis in favour of the CTG-alone group (metabolic acidosis being defined as a pH < 7.05 and base excess < –12 mmol/l). This is worrying because if confirmed in a larger study, such a difference could result in a poorer neonatal outcome. This finding contrasts with that of the previous study of AmerWahlin.2 Because of the importance of this outcome, we consider that the study was underpowered. Ojala et al. based their power calculation on the incidence of a neonatal umbilical artery pH < 7.10 rather than a pH < 7.05, which is more stringent and relevant to outcome. When using the lower cutoff level in pH, the incidence of neonatal acidaemia will be lower and the required sample size will therefore be higher. In general, the power of a study must be based on the primary endpoint, and this endpoint should be the same in both the power calculation and the final analysis. Second, although again not statistically significant, there is a 1.7% lower overall caesarean section rate in the CTG group. Little attention is paid to this important finding. No information is available about the rate of caesarean sections performed for failure to progress or a combination of failure to progress and fetal distress. It may be that the indications for caesarean section were significantly different in the two groups. In summary, we feel that the study of Ojala et al. raises concerns about fetal outcome when using STAN. In view of this concern, we have started a randomised clinical trial comparing CTG + STAN with CTG + FBS, with a larger sample size. j

Neonatal complications of term pregnancy: Rates by gestational age increase in a continuous, not threshold, fashion

The purpose of this study was to determine whether, when, and how rates of short-term neonatal complications increase beyond 37 weeks of gestation. A retrospective cohort study was conducted of all low-risk, term, cephalic, and singleton births that were delivered at the University of California, San Francisco, between 1976 and 2001. Primary outcomes included neonatal umbilical artery pH, umbilical artery base excess, the presence of meconium, macrosomia, 5-minute Apgar scores, and admission to the intensive care nursery. Multivariate analyses were performed that controlled for maternal ethnicity, weight, age, socioeconomic status, and obstetric history. Among the 32,679 women who were delivered at > or =37 completed weeks of gestation, the rates of umbilical artery pH <7.0, umbilical artery base excess less than -12 increased beyond 40 weeks of gestation, and the presence of meconium increased beyond 39 weeks of gestation (chi-squared test; P < .001). These outcomes continued to increase in each subsequent week, and these findings persisted when they were controlled for potential confounders in multivariate models. We found that the rates of immediate neonatal morbidity increase with increasing gestational age. Accurate determination of these rates is important in the determination of gestational age at which the risk of continuing the pregnancy outweighs the risk of induction of labor.

Neonatal complications of term pregnancy: rates increase in a continuous, not threshold fashion

To determine when rates of short-term neonatal complications increase beyond 37 weeks of gestation. A retrospective cohort study of all term, cephalic, singleton births delivered at an academic medical center between 1976 and 2001. Data were abstracted from a research quality database and verified with chart review when in question. Primary outcomes included neonatal umbilical artery pH (uapH) and base excess (uaBE), as well as the presence of meconium, 5-minute Apgar scores, and admission to the NICU. Multivariate analyses were performed controlling for maternal ethnicity, weight, age, socioeconomic status, and obstetric history. We found that among the 36,241 women who delivered at 37 completed weeks and beyond, the rates of uapH <7.0, uapH <7.10, uaBE ≤10, and uaBE ≤12, and the presence of meconium all increased throughout term gestations (chi-square, P<0.001). These results persisted when controlling for potential confounders in multivariate models. We found that the rates of immediate neonatal morbidity increase with increasing gestational age. Accurate determination of these rates is important in determining at what gestational age the risk of continuing the pregnancy outweighs that of induction of labor.Tabled 1Weeks of Gestation vs Short-Term Neonatal ComplicationsGestational Age (n)uaBE ≤12 (P<0.001)uapH<7.0 (P<0.001)Meconium (P<0.001)37-39 (15,712)0.87%0.77%15.6%40 (10,873)0.89%0.50%25.8%41 (6,336)1.72%1.09%31.9%42 (2,563)2.03%1.43%35.4%≥43 (747)2.68 %1.33 %37.2 % Open table in a new tab

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Multicenter study on the clinical value of fetal pulse oximetry: I. Methodologic evaluation

Objective: Our purpose was to evaluate the feasibility of intrapartum fetal pulse oximetry, the distribution of fetal oxygen saturation values, and the relationship with the neonatal outcome in a population with an abnormal fetal heart rate. Study Design: A prospective multicenter observational study was performed from June 1994 to November 1995. Fetal oxygen saturation was continuously recorded with use of a Nellcor N-400 fetal pulse oximeter in case of an abnormal fetal heart rate during labor. Simultaneous readings of fetal oxygen saturation and fetal blood analysis were obtained at inclusion and before birth. Feasibility, adverse effects, distribution of fetal oxygen saturation values, and relationship with neonatal outcome were assessed. Results: One hundred seventy-four patients were included. From 172 attempted sensor placements, the procedure was impossible in three cases and fetal oxygen saturation values were obtained in 164 cases (95.3%). Physicians considered sensor placement an easier task than an attempt at fetal blood analysis (easy in 87.5% vs 78.9% for fetal blood analysis, p = 0.03). The mean reliable signal time (±SD) was 64.7% ± 32% during the first stage. There were no serious adverse effects in the study population. The mean fetal oxygen saturation during the first stage of labor was 42.2% ± 8.0% (10th to 90th percentile range 30% to 53%). Fetal oxygen saturation was significantly correlated with scalp pH ( r = 0.29, p = 0.01) but not with neonatal umbilical artery pH or gas values. There was a significant association between low fetal oxygen saturation (<30%) and poor neonatal condition. Conclusion: The feasibility of fetal pulse oximetry is satisfactory in clinical practice. It is easy to use and provides a fair rate of recorded values, even in a population with suspicion of fetal distress. A low fetal oxygen saturation is significantly associated with an abnormal neonatal outcome.