Fetal Blood pH Research Articles

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

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

Evaluation of fetal acidemia during delivery using the conventional 5-tier classification and Rainbow systems.

The association between prepartum time-series fetal heart rate pattern changes and cord blood gas data at delivery was examined using the conventional 5-tier classification and the Rainbow system for 229 female patients who delivered vaginally. They were classified into three groups based on the results of umbilical cord blood gas analysis at delivery. The fetal heart rate pattern classifications were based on analysis of measurement taken at 10-min intervals, beginning at 120 min pre-delivery. The relationship between fetal heart rate pattern classification and cord blood pH at delivery changed over time. The 5-tier classification at each interval increased before delivery in the Mild and Severe groups compared with the Normal group. No significant differences were observed between acidemia groups. The Rainbow classification showed a significant differences between the acidemia groups at each interval, particularly during the prepartum period. A relationship between classification and outcome was evident before delivery for both the 5-tier classification and Rainbow system.

Relationship between Cardiofemoral Index and Fetal Blood pH in Fetuses with Rh Alloimmunization

Relationship between Cardiofemoral Index and Fetal Blood pH in Fetuses with Rh Alloimmunization

Determination of Foetal Scalp Blood Sampling pH as an Indicator of Loss of Foetal Well-Being in Women Undergoing Caesarean Section

Asphyxia during birth is one of the three leading causes of neonatal morbidity and mortality among newborns carried to term. The objective of this study was to evaluate the measurement of the foetal scalp blood pH as a measure of foetal status, evaluating: cord gases, meconium-stained fluid, APGAR score or the need for neonatal resuscitation in pregnant women undergoing caesarean sections. A cross-sectional study was carried out over a period of 5 years (2017-2021) at the Hospital de Poniente (southern Spain). A total of 127 pregnant women participated from whom a foetal scalp blood pH sample was taken and used to indicate the need for an urgent caesarean section. The results showed a correlation between the pH of the scalp blood and the pH of the umbilical cord artery, umbilical cord vein (Rho of Spearman arterial pH: 0.64, p < 0.001; Rho of Spearman venous pH: 0.58, p < 0.001) and the APGAR test one minute after delivery (Spearman's Rho coefficient of 0.33, p < 0.01). These results suggest that the foetal scalp pH should not be considered a foolproof method to indicate an urgent caesarean section. Foetal scalp pH sampling can be used as a complementary test, in conjunction with cardiotocography, to indicate whether an emergency caesarean section is necessary due to loss of foetal well-being.

Association of CTG Diagnosis of Intrapartum Fetal Distress and Immediate Postpartum Acidemia in Foetal Umbilical Artery.

Intrapartum fetal hypoxia which is one of the leading causes of neonatal morbidity and mortality is a preventable cause. Over the past years, many methods have been employed to diagnose fetal distress, a sign of fetal hypoxia, among these, cardiotocography (CTG) is the most widely used method. Diagnosis of fetal distress based on CTG can have high inter and intraobserver variation leading to either delayed or inessential intervention henceforth increasing maternal morbidity and mortality. Fetal cord arterial blood pH is an objective method to diagnose intrapartum fetal hypoxia, hence by observing the incidence of acidemia in cord blood pH among those newborns born through cesarean section (CS) in view of non-reassuring CTG can help make a judicious decision. In this single institutional observational study, patients admitted for safe confinement were subjected to CTG in the latent and active phases of labor. Non-Reassuring traces were further classified based on NICE guideline CG190. The cord blood of these neonates born through CS in view of non-reassuring CTG was drawn and sent for ABG analysis. Among the 87 neonates delivered through CS in view of fetal distress, 19.5% had acidosis. Among those with pathological traces, 16(28.6%) had acidosis and one (100%) which was categorized as the need for urgent intervention showed acidosis. This result showed a statistically significant association (p value-0.003). No statistically significant association was obtained when variation in baseline characters of CTG when taken independently. In our study, neonatal acidemia which is the objective evidence of fetal distress was seen in 19.5% of our study population who underwent cesarean in view of non-reassuring CTG. Among these, acidemia was significantly associated with pathological CTG trace compared to suspicious trace. We also observed that abnormal FHR features when taken independently showed no significant association with acidosis. Acidosis among newborns certainly increased the requirement for active resuscitation and additional hospital stay. Hence, we conclude that by recognizing specific fetal heart rate patterns associated with acidosis in a fetus, a more judicious decision can be made, thereby preventing both delayed as well as inessential intervention.

Correlation between deceleration area and fetal cord blood pH in neonates with meconium-stained amniotic fluid

Correlation between deceleration area and fetal cord blood pH in neonates with meconium-stained amniotic fluid

Can we improve our ability to interpret category II fetal heart rate tracings using additional clinical parameters?

This study examined predictive factors, in addition to Category II Fetal Herat Rate (FHR) monitoring that might imply fetal acidosis and risk of asphyxia. This retrospective cohort study compared three groups of patients with Category II FHR monitoring indicating need for imminent delivery. Groups were divided based on fetal cord blood pH: pH≤7.0, 7.0<pH<7.2 and pH≥7.2. Demographics, medical history, delivery data and early neonatal outcomes were reviewed. The cohort included 417 women. Nine (2.2%) had cord pH≤7.0, 105 (25.2%) pH 7.0 to 7.2 and 303 (72.6%) ad pH≥7.2. Background characteristics, pregnancy follow-up and intrauterine fetal evaluation prior to delivery were similar in all groups. As expected, more patients in the low pH group had cesarean section (55.6%), than vaginal delivery or vacuum extraction (p=0.02). Five-minute Apgar scores were similar in all groups. This retrospective study did not detect a specific parameter that could help predict the prognosis of fetal acidosis and risk of asphyxia. As we only included patients with a Category II tracing that was worrisome enough to lead to imminent delivery, it is reasonable to believe that this is due to patient selection, meaning that when the Category II FHR results in decision for prompt delivery, there is no added value in additional clinical characteristics. The evaluation should be expanded to all patients with Category II tracing for better interpretation tools for Category II FHR monitors, as well as a larger study population.

Safety, speed, and effectiveness of air transportation for neonates.

In Japan, 44.3% of neonates are delivered in private clinics without an attending pediatrician. Obstetricians in the clinics must resuscitate asphyxiated neonates in unstable condition, such as respiratory failure, and they are frequently transferred to tertiary perinatal medical centers. There has been no study comparing the physiological status and prognosis of neonates transported by ambulance with those transported by helicopter. Medical and transport records were used to compare the physiological status of neonates transported to Kagoshima City Hospital by land and those transported by air between January 1, 2013, and December 31, 2017. Data from 425 neonates transferred by land and 143 by air were analyzed. There were no significant differences between the two groups in mean gestational age, mean birthweight, fetal blood pH, Apgar score, or the Score for Neonatal Acute Physiology with Perinatal Extension-II (SNAPPE-II) on arrival to the tertiary center (16.3±15.4 [95% confidence interval (CI): 13.2-17.7] vs 16.4±15.4 [95% CI: 13.9-19.0], respectively; P=0.999); both groups had SNAPPE-II score 10-19, indicating no difference in mortality risk. The times to starting first aid and to admission to the intensive care unit were significantly reduced in neonates transported by air than by land. In subgroup analysis of patients of a gestational age ≤28weeks, all cases of severe intraventricular hemorrhage (IVH) were observed in the land transportation group. Neonatal transportation by air is as safe as land transportation, and time to first aid and intensive care are significantly reduced by transportation by air than by land. Air transport could also contribute to the prevention of IVH in neonatal transportation.

FETAL OUTCOME AFTER CAESAREAN SECTION PERFORMED FOR FETAL DISTRESS BASED ON ABNORMAL CARDIOTOCOGRAPHY

Objective: To determine the fetal outcome of Caesarean Sections (CS) performed for abnormal Cardiotocography (CTG)&#x0D; Material and Methods: This retrospective data review was conducted in Gynaecology and Obstetrics unit B of Lady Reading Hospital Peshawar from June 2015 till June 2016 after approval from the hospital ethical committee, using a non-probability convenient sampling technique. The hospital record of 234 patients who had CS for fetal distress was reviewed. Patients with singleton and term gestation, who had CS for fetal distress diagnosed based on abnormal Cardiotocography were included in the study. The fetal outcome was noted in terms of Apgar score at 5 minutes, admission to neonatal intensive care unit (NICU), and perinatal mortality. Fetal blood sampling (FBS) and postnatal analysis of fetal arterial blood gases and PH were not carried out in any patient because of non-availability. The results are expressed in frequencies and percentages, shown in tables and figures.&#x0D; Results: In one year, a total of 1255 C-sections were performed. Amongst these, 234 (18.64%) patients fulfilling inclusion criteria were enrolled. Babies delivered with 5 minutes Apgar score of 7 or above were 166 (70.94%). Twenty-one (8.97%) babies were admitted to NICU and perinatal mortality was 6 (2.54%). &#x0D; Conclusion&#x0D; Out of 234 patients who underwent CS due to abnormal CTG, more than 2/3rd of patients had normal babies with an Apgar score of 7 or more, which indicates that abnormal CTG alone should not be used as an indication for CS&#x0D; Keywords: Fetal Distress, CTG, Caesarean section

Fetal cerebral perfusion is better than fetal acidaemia for the prediction of brain injury and might be assessable by sophisticated fetal heart rate metrics.

As Georgieva et al point out in this issue of BJOG, the relationship between fetal blood pH and intrapartum brain injury is poor. In contrast, fetal cardiovascular decompensation (CVD) leads via dropping fetal systemic arterial blood pressure (ABP) to a precipitous fall in cerebral perfusion pressure (CPP), resulting in cerebral ischaemia and injury.

Local cerebroplacental ratio reference ranges are better predictors for adverse delivery outcomes in normal weight fetuses during pregnancy

Objective To evaluate the predictive value of local versus external cerebroplacental ratio (CPR) reference ranges for delivery outcomes in low-risk pregnancies. Methods A retrospective analysis of all feto-maternal demographic and biometric data in fetuses with normal estimated fetal weight (EFW) and a CPR examination between the years 2014–2019, in a university medical center. The study group included healthy singleton pregnancies from 32-week gestation, with an examination-to-delivery interval of <31 days. The three models compared two thresholds: <5th percentile (CPR 1, CPR 3) and <10th percentile (CPR2). The CPR1 and CPR2 models both use local CPR reference ranges, while the CPR3 model uses an external CPR reference range. The main outcome was predictive accuracy for urgent cesarean delivery (CD), operative delivery (OD), and composite outcome (CO), defined as an Apgar score of <7, fetal blood pH < 7.1 or admission to the neonatal intensive care unit (NICU). Results Overall, 410 low-risk pregnancies with normal weight fetuses were enrolled in the study. All three CPR models turned out to be significant predictors of CD, with an odds ratio (OR) of 9, 95% CI (2.7–27), p < .001 for CPR1, and an OR of 2.9, 95% CI (1.1–7.4), p < .04 for CPR2, and an OR of 3.4, 95% CI (1.7–6.8), p < .001 for CPR3. All the three models were also found to be predictors of OD, and an OR of 6.9, 95% CI (2.1–22) p < .04 for CPR1, and an OR of 2.8, 95% CI (1.2–6.7), p < .04 for CPR2, and an OR of 2.8, 95% CI (1.4–5.3) p < .01 for CPR3. The positive predictive values (PPV) for CD and OD were both 50% for CPR1, versus 28% and 26% in CPR2, and 24% and 25% in CPR3. The negative predictive value (NPV) was similar, around 88% in all three models. None of the models were found to be significant predictors for CO. Conclusions A CPR model based on local reference ranges and <5th percentile cutoffs showed the highest PPV for CD and OD. The calculation of local references for CPR should be encouraged.

Early Effect of Epidural Analgesia on Fetal Acid-base Balance in the First Stage of Labour

Introduction: Epidural analgesia is a consolidated therapeutic technique generally used for the relief of labor pain. Since its introduction in obstetrics, there have been many studies that evaluate the effect that this type of analgesia has over the course of labor, and its possible repercussions on the mother and the fetus/newborn by analyzing data at birth. However, there exist very few studies that analyze the early effect that epidural analgesia has on the fetus. Objectives: The main objective of this study is to analyze the early effects of epidural analgesia on the fetal status by evaluating the possible changes in the acid-base fetal state, the most precise way to evaluate fetal wellbeing during labor, and cardiotocographic (CTG) tracing of the fetal heart rate after the administration of an epidural. Methods: This is a prospective study of 193 patients, in which a determination of the fetal acid-base equilibrium was done before the administration of epidural analgesia and repeated 60 min afterwards, evaluating possible changes in the results motivated by analgesia. Results: There was a statistically significant descent on fetal blood pH after the administration of epidural analgesia, as well as a significant increase in the number of fetal heart traces with alterations. The descent of fetal pH was greater in patients that had some gestational associated conditions. Conclusion: The administration of epidural analgesia during the first stage of labor caused, as an early effect, a significant descent in fetal blood pH, without that descent being clinically relevant over the fetal status in healthy fetuses. There must be a strict control in fetuses with some initial alteration in the CTG tracings.

Assessing the impact of total extracorporeal circulation on hemodynamics in an ovine fetal model.

The present study aimed to evaluate the impact of total extracorporeal circulation on hemodynamics and placental function in an ovine fetal model. Mid-term ovine fetuses (n=6) underwent extracorporeal circulation (30 min), cardioplegic arrest (20 min) and monitoring (120 min). The ascending aorta and umbilical cords of the fetuses were occluded during the bypass and an extracorporeal membrane oxygenator was used as the oxygen source. Biventricular intracardiac pressures, echocardiographic data, blood gas levels and placental function variables were recorded, and statistical analysis was performed using the repeated-measure analysis of variance test. The data indicated that fetal heart rate and blood pressure at 30, 60, 90 and 120 min following the bypass were stable relative to pre-arrest baseline (pre-bypass) values (P>0.05). However, end diastolic pressures in the ovine right ventricles post-bypass were significantly increased at 30, 60, 90 and 120 min relative to pre-bypass pressures (P<0.05). The pulsatility index also increased at 30 min post-bypass relative to the pre-bypass score (0.91±0.06 vs. 0.61±0.14; P=0.007). The mean resistivity index at all time points post-bypass was consistent with the pre-bypass score (P>0.05), while the mean Tei index values for the left and right ventricles post-bypass were significantly higher at all time points relative to pre-bypass values (P<0.05). The pre-bypass fetal blood pH, SaO2, base excess and lactate values were maintained during arrest (P>0.05). Fetal hemodynamics and placental function additionally remained stable for up to 2 h upon reperfusion following total extracorporeal circulation and cardioplegic arrest. Collectively these data suggest that the reproducible ovine fetal model may be useful in the evaluation of fetal cardiac surgery.

Comparison of different doses of Fentanyl for prevention of hemodynamic changes during induction and intubation in parturients undergoing caesarian section under general anesthesia.

Introduction: Present study was designed to find low, safe and efficacious dose of fentanyl to avoid its foetal side effects by comparing two doses of fentanyl to prevent haemodynamic hazards at induction and intubation in patients undergoing caesarean section (CS) under general anaesthesia (GA). Method: Forty five full term parturients posted for emergency/elective caesarean section under GA of ASA Grade I or II, age group between 18 to 35 years were randomly distributed into three groups. Intravenous fentanyl 0.5µg/kg or1µg/kg diluted to 5 ml or normal saline 5 ml was administered three minutes before induction in Group F 0.5, Group F1or Group C respectively. Maternal haemodynamic parameters and foetal parameters were recorded at different time intervals. Results: Group F and Group F1 showed significant reduction and stability in maternal haemodynamics when compared with the control group, but no statistical difference was observed amongst them. No difference was observed in foetal Apgar score and cord blood pH in all three groups. Conclusion: Fentanyl in doses as low as 0.5µg/kg can be used safely in parturients to prevent haemodynamic hazards at intubation in patients undergoing CS under GA.

Short-term neonatal outcome in diabetic versus non-diabetic pregnancies complicated by non-reassuring foetal heart rate tracings

Objective: Analysis of the impact of non-reassuring foetal heart rate patterns (FHR) and suspected foetal distress during active labour on the neonatal outcome in diabetic compared to non-diabetic mothers.Methods: Retrospective case–control study comparing the short-term neonatal outcome including Apgar score at 5 min, and arterial/venous umbilical cord blood pH of 57 deliveries of women with different types of diabetes and 114 healthy controls. Patients were selected out of all deliveries with suspected foetal distress during active labour and performed foetal scalp pH samplings (n = 590) at the Medical University of Graz, Austria, during 2008–2009.Results: Arterial pH was significantly lower in the diabetic group (7.215 versus 7.250, p = 0.007). Apgar scores ( > 8) at 5 min were similar in both groups (96.5% versus 95.6%, p = 0.566). The percentage of cases with foetal scalp blood pH <7.25 was higher in the diabetes group, but did not reach statistical significance (14.1% versus 7.1%, p = 0.166).Conclusions: Newborns of women with gestational and type 1 diabetes and non-reassuring FHR tracing have significantly lower arterial cord blood pH values without consequences on neonatal postpartum adaptation. Special attention to pathological changes in FHR patterns and to the more rapid decline in foetal pH during periods of foetal distress may be warranted in women with gestational and pre-conceptional diabetes during active labour. More frequent foetal scalp pH testing to rule out clinically relevant foetal acidosis needs to be discussed.

The reliability of foetal blood sampling as a test of foetal acidosis in labour

To establish whether foetal blood sampling for pH is a reliable test of foetal acidosis in labour by comparing paired foetal blood samples taken at a single procedure. We conducted a prospective study assessing 293 consecutive attempts at foetal blood sampling in labour over a four month period from February to May 2012. A total of 100 paired samples were suitable for analysis. We compared the consistency of pH results of paired foetal blood samples, evaluated cases where inconsistent results would result in conflicting clinical decisions, and explored factors associated with discordant results. There was a statistically significant difference between the mean pH of the two samples: 7.297 (SD 0.065) versus 7.315 (SD 0.059), p<0.0005. Of the 100 paired samples, 43 had a difference greater than the laboratory acceptable maximum analytical difference of 0.038. There was discordance between the samples in 16 cases with results crossing a decision threshold, and in 11 cases (69%) delivery was by emergency caesarean section. Inconsistent results were not associated with specific clinical factors and occurred more often with senior operators. Foetal blood sampling is considered by many as the gold standard in assessing intrapartum foetal wellbeing. We have demonstrated inconsistency of paired foetal blood pH results which suggests that foetal blood sampling should not be considered infallible.

Authors’ Response

We would like to thank Professor Joachim Dudenhausen for his comments [ [1] Dudenhausen J.W. The aim of FBS in labour is to detect hypoxia. Eur J Obstet Gynecol Reprod Biol. 2011; https://doi.org/10.1016/j.ejogrb.2011.09.018 Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar ]. Ours is an Opinion article and our objective is not to answer the question but to appraise the existing evidence regarding use of FBS as a gold standard diagnostic technique for foetal distress and its role in reducing caesarean section. 1.As Professor Dudenhausen implies, FBS is frequently and imprecisely said to detect foetal distress. This assumption is inaccurate, as foetal distress comprises many different pathologies. Hence we suggest in our Opinion that the use of FBS as an adjunct to foetal monitoring in labour is primarily to detect hypoxia rather than foetal distress [ [2] Mahendru A.A. Lees C.C. Is intrapartum fetal blood sampling a gold standard diagnostic tool for fetal distress. Eur J Obstet Gynecol Reprod Biol. 2011; 156: 137-139 Abstract Full Text Full Text PDF PubMed Scopus (26) Google Scholar ]. 2.Studies related to the influence of caput succedaneum do suggest that there are exceptions where results of FBS are affected in cases of prolonged labour [ [3] Saling E. Dudenhausen J.W. The present situation of clinical monitoring of fetus during labour. J Perinat Med. 1973; 1: 75 Crossref PubMed Scopus (10) Google Scholar ]. Our emphasis is not purely on theoretical measurement errors, which have been extensively investigated, but also on the application of the technique in day-to-day practice [ 2 Mahendru A.A. Lees C.C. Is intrapartum fetal blood sampling a gold standard diagnostic tool for fetal distress. Eur J Obstet Gynecol Reprod Biol. 2011; 156: 137-139 Abstract Full Text Full Text PDF PubMed Scopus (26) Google Scholar , 4 Sherman D.J. Arieli S. Raziel A. Bukovsky I. The effect of sampling technique on measurement of fetal blood pH and gases – an in vitro system. Am J Obstet Gynecol. 1994; 171: 1125-1128 Abstract Full Text PDF PubMed Scopus (10) Google Scholar ]. 3.We discuss the study of tissue pH measurements with a glass electrode in the context of its forming part of the evidence cited by the UK National Institute for Clinical Excellence (NICE) guidance in its consideration of FBS in intrapartum care [ [5] NICE Guideline Intrapartum care, care of healthy women and their babies during childbirth. 2007 Google Scholar ]. This is the only prospective cohort study regarding the validity of foetal pH to detect foetal hypoxia [ [6] Weber T. CTG supplemented with continuous fetal pH monitoring during labour. Acta Obstet Gynecol Scand. 1982; 61: 351-355 PubMed Google Scholar ]. It is true that the study tests a different technique – that of continuous tissue pH assessment, which is different from intermittent foetal blood sampling – but it would be incorrect to suggest that the aim of both techniques is not to measure foetal pH. 4.We do not state that the decision for FBS to produce a result always takes 18 min. This figure is based on the only study we can find on the matter [ [7] Tuffnell D. Haw W.L. Wilkinson K. How long does a fetal scalp blood sample take?. BJOG. 2006; 114: 192-202 Google Scholar ] and highlights the fact that there are cases where this delay may itself lead to harm by slowing a delivery in the context of severe foetal hypoxia. We are unaware of any evidence to suggest that training reduces the time to FBS and are aware of situations where experienced operators take significantly longer. Is intrapartum fetal blood sampling a gold standard diagnostic tool for fetal distress?European Journal of Obstetrics and Gynecology and Reproductive BiologyVol. 156Issue 2PreviewDeveloped in 1960s, cardiotocography is a screening test and fetal blood sampling (FBS) is an adjunctive, diagnostic technique to detect fetal hypoxia. A fetal blood sample pH value of less than 7.20 has a higher specificity than a pathological CTG to predict low Apgar score at 1 min. Though with a pathological CTG and despite a normal FBS pH value the risk of delivering a hypoxic infant is 30–50%, FBS has assumed considerable importance in purportedly reducing unnecessary obstetric intervention. Full-Text PDF The aim of FBS in labour is to detect hypoxiaEuropean Journal of Obstetrics and Gynecology and Reproductive BiologyVol. 161Issue 1PreviewMahendru and Lees from the Dept. of Fetal Medicine, Cambridge University Hospitals [1] recently answered with an ‘Expert Opinion’ the question, “Is intrapartum fetal blood sampling a gold standard diagnostic tool for fetal distress?” I comment on the following four points raised in their paper: Full-Text PDF

Fetal scalp stimulation test: An adjunct to intermittent auscultation in non‐reassuring fetal status during labor

To evaluate fetal scalp stimulation test (FSST) as an adjunct to intermittent auscultation in diagnosis of intrapartum fetal acidosis and associate result of FSST with cord blood pH and immediate neonatal outcome. This study was conducted at a tertiary hospital in India. Digital FSST was performed in seven hundred and fifty women in labor with singleton gestation ≥37 weeks, cephalic presentation and fetal heart abnormalities and/or thick meconium stained amniotic fluid. Intermittent auscultation was used for fetal monitoring during labor. The outcome measure was cord blood pH < 7.20 and neonatal morbidity. The non-reactive FSST is associated with lower umbilical cord blood pH, lower Apgar scores and higher asphyxia related neonatal morbidity (P-value < 0.001). The non-reactive FSST had 41% sensitivity and 84% specificity to detect pH < 7.20. The positive predictive value of FSST for fetal acidosis is 44% and negative predictive value is 83%. The likelihood ratio for acidosis with noncreative FSST is 2.57. Non-reactive FSST is associated with adverse neonatal outcomes. The positive and negative predictive values of FSST to diagnose fetal cord blood pH < 7.20 during labor are 44% & 83%, respectively.

Metabolic effects of ritodrine hydrochloride in the pregnant sheep.

The effects of ritodrine hydrochloride on maternal and fetal arterial blood pH and pCO2, plasma electrolytes and maternal plasma glucose and free fatty acid levels were investigated in the third-trimester pregnant sheep. Ritodrine produced a slight fall in the maternal and fetal arterial pH without changes in the arterial pC02. The pH values were, however, within a normal range. Increases in the maternal plasma glucose and free fatty acid levels were also observed. Although maternal and fetal plasma sodium and chloride concentrations did not change, the potassium decreased in a dose-dependent manner both in the ewe and in the fetus following sequential ritodrine infusion. Constant infusion of ritodrine (3 mcg/kg/min), which is a sufficient dose to inhibit uterine contractions, also resulted in a significant decrease in the maternal plasma potassium concentration. It appears to be necessary to give attention to the metabolic effects of ritodrine in long-term therapy of premature labor.

Fetal and offspring arrhythmia following exposure to nicotine during pregnancy

Although recent studies have demonstrated prenatal nicotine can increase cardiovascular risk in the offspring, it is unknown whether exposure to nicotine during pregnancy also may be a risk for development of arrhythmia in the offspring. In addition, in previous studies of fetal arrhythmia affected by smoking, only two patterns, bradycardia and tachycardia, were observed. The present study examined acute effects of maternal nicotine on the fetal arrhythmia in utero, and chronic influence on offspring arrhythmia at adult stage following prenatal exposure to nicotine. Nicotine was administered to pregnant ewes and rats. In the fetal sheep, intravenous nicotine not only induced changes of fetal heart rate, but also caused cardiac cycle irregularity, single and multiple dropped cardiac cycles. Although maternal nicotine had no influence on fetal blood pH, lactic acid, hemocrit, Na(+), K(+) levels and plasma osmolality, fetal blood PO(2) levels were significantly decreased following maternal nicotine in ewes. In offspring rats at 4-5 months after birth, prenatal exposure to nicotine significantly increased heart rate and premature ventricular contraction in restraint stress. In addition, arrhythmias induced by injection of nicotine were higher in the offspring prenatal exposure to nicotine in utero. The results provide new evidence that exposure to nicotine in pregnancy can cause fetal arrhythmia in various patterns besides tachycardia and bradycardia, the possible mechanisms for nicotine-induced fetal arrhythmia included in utero hypoxia. Importantly, following exposure to nicotine significantly increased risk of arrhythmia in the adult offspring. The finding offers new insight for development of cardiac rhythm problems in fetal origins.